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1. cee ccc eecececeeceseecescnseeceecesens 117 Bio 2 CLOSS DIOCeESSING xicesa ate asisccenuiebitiwniacde caus bor E E S 118 325 3 CVU toned IIMdG O eese a aaar 119 3 5 4 Removal of red eye effect s ssssssessseseseseseseseseseseseseseseseseseseseses 120 AA WE GNC MING ea a a a a a Ne 123 AT OVERVIEW aea a a AARG 124 Aes We CIC a E A 124 4 2 TECheErnng Dane Enas a a a a re 125 OF Ne SESSO ea a a aa a a r 125 AZ 2 MING VEW iiras A a A A 125 A723 Camera SENOS aeii Eer a 125 AF EXO COS a terns e a Mensa al a 126 4 3 1 Studio setup with screening cece ccecescesceceececcecesceseecesceseucescesees 126 432 CapEunring a LIMela PSE ornina cedeionwousried aes a Aa 126 JA VEOUDIC SOO G actcttanaitsscusanstatuonsenctsandies AA 127 4 4 1 Verify that your camera is supported cece cec ccc eececeeceseeseeceseeees 127 AAD SO NOW WOE scvaicsscuitin ds oss nete N TE AEEA sab nels oa Bead ool ETT 127 DVI eID ESEP E cc wawsdcea E A nda beats wae A pace A ave E E E sees 129 Bes OVON OW ctr iticadenetacetia ie eacasisatiatincatesstocedianim A a a RE 130 St ie pi ga Map VEW ap amma Can ee me a a a aa 130 Same MIP NE gm e aR oe OR SCREEN CEA CRC ASR PEE ORTON ar OT ey rea 131 5 2 li Lert Panels sux seiicels vith hates a aa hla A A 131 BZ PNG NOC ACIONN Saas cacensdoiasA nates A 131 5 2 5 Map sE EINS coun dace tated inci tet tae st let tee ate det ah iat cua 131 SLA TAGGING ee aa a a a a aa 132 G S UdESNOW Siisina ar
2. boolean Exports an image to a file This is a blocking operation that will not return until the image is exported Attributes e jimplicit_yield 195 self types dt_imageio_module_format_t The Format that will be used to export image types dt_lua_image_t The image object to export Filename string The filename to export to return boolean Returns true on success 8 2 2 3 types dt_imageio_module_format_data_png dt_type Type object describing parameters to export to png Attributes e parent types dt_imageio_module_ format _t types dt_imageio_module_format_data_png bpp number The bpp parameter to use when exporting Attributes e write 8 2 2 4 types dt_imageio_module_format_data_tiff dt_type Type object describing parameters to export to tiff Attributes e parent types dt_imageio_module_format_t types dt_imageio_module_format_data_tiff bpp number The bpp parameter to use when exporting Attributes e write 8 2 2 5 types dt_imageio_module_format_data_exr 196 dt_type Type object describing parameters to export to exr Attributes e parent types dt_imageio module format _t types dt_imageio_module_format_data_exr compression String The compression parameter to use when exporting Attributes e write 8 2 2 6 types dt_imageio_module_format_data_copy dt_type Type object describing parameters to export to copy Attributes e parent types dt_imageio_module_ format _t 8 2 2 7 types dt_imageio_module_f
3. and ISO settings The darktable team with the help of many users has measured noise profiles For various cameras Differentiated by ISO settings we evaluated how the noise statistics develop with brightness For the three color channels Our set of profiles already covers about 100 popular camera models from all major manufacturers Based on EXIF data of your RAW file darktable will automatically determine the camera model and ISO setting IF Found in its database the corresponding noise profile will be used IF your image has an intermediate ISO value the statistical properties will be inter polated between the two closest datasets in the database and this interpolated setting will show up as the First line in the combo box You also have the option to manually over write this selection to suit your personal preferences better The top most entry in the combo box brings you back to the profile darktable deems most suited This module can eliminate noise with two different core algorithms non local means is a bit better suited to tackle luma lightness noise wavelet has its strength in elim inating chroma color noise IF needed you can apply two instances of this module see Section 3 2 4 Multiple instances The non local means instance should be combined with blend mode lightness or HSV lightness the wavelet instance with blend mode color or HSV color For more information on b
4. You can control the brush width its hardness and its opacity Absolute control means that the pressure reading directly defines the attribute with a value between 0 and 100 Relative means that the pressure reading adjusts the attribute between zero and the pre defined default value default off smoothing of brush strokes Sets the level for smoothing of brush strokes Stronger smoothing leads to less nodes and easier editing at the expense of lower accuracy ask before deleting a tag Always ask user before deleting a tag from an image default on only draw images on map that are currently collected and filtered Use the current filter settings to select the geotagged images drawn in the map view This limits the images drawn to those currently shown in the filmstrip and thus reduces the time needed default off maximum number of images drawn on map The maximum number of geotagged images drawn on the map Increasing this number can slow down the drawing of the map Needs a restart if changed default 100 pretty print the image location Show a more readable representation of the geo location in the image information mod ule default on 139 expand a single lighttable module at a time Controls how lighttable panels are expanded IF this option is enabled expanding a panel by clicking collapses any currently expanded panel IF you want to expand a panel without collapsing the others you do so with shift cli
5. darktable uses Lua http www lua org which is an independent project Founded in 1993 providing a powerful Fast lightweight embeddable scripting language Lua is wide ly used by many open source applications in commercial programs and for games pro gramming darktable uses Lua version 5 2 Describing the principles and syntax of Lua is beyond the scope of this usermanual For a detailed introduction see the Lua reference manual http www lua org manual 5 2 manual html 8 1 1 Basic principles At startup darktable will automatically run two Lua scripts e ascript called luarcin SDARKTABLE share darktable e ascript called luarcin the user s configuration directory SDARKTABLE is used here to represent your system s darktable installation directory This is the only time darktable will run Lua scripts by itself The script can register callbacks to perform actions on various darktable events This callback mechanism is the primary way to trigger lua actions 8 1 2 A simple lua example Let s start with a simple example We will print some code on the console Create a file called uarc in darktable s configuration directory usually config darktable and add the Following line to it Printe THeLlo World 2 Start darktable and you will see the sencence Hello World printed on the console Nothing Fancy but it s a start At this point there is nothing specific to darktable in the script We simply use the stan da
6. will cer tainly cause some noticeable slow down 3 2 4 2 Managing instances When clicking on the E icon a drop down menu will new instance duplicate instance appear sone move down Selecting new instance generates a new module instance above any existing ones All parameters are set to default values The new instance gets its own complete set of GUI controls and a number appended to the base module name for distinction Selecting duplicate instance behaves in a similar way The only difference the new in stance will inherit all parameter settings from its parent darktable applies all modules in a defined order according to their type Therefore all in stances of a particular module will occur together in the pixelpipe You can however de cide on the relative order in which the different instances of a module are applied by se lecting move up or move down to shift the position of the instance among its peers To delete an instance just press delete from the drop down menu 3 2 5 Blending 3 2 5 1 Overview By default a module takes its input from the preceding module performs its calculations and handles its output over to the next module in the pixelpipe On demand you can ac tivate an additional step where a module s output is reprocessed with its input before giving the result to the next module This additional processing step is called blending Input and output can be processed
7. This module offers enormous artistic potential albeit with results that are sometimes difficult to predict 108 radius Set the radius of the blur soften with This combobox defines the blur algorithm you can choose between gaussian blur de Fault and bilateral Filter The latter leads to an edge preserving blur gaussian will blur all image channels L a and b bilateral will only blur L channel contrast Changes the contrast Negative values result in an inverted negative image Higher ab solute values increase contrast lower absolute values reduce contrast A value of zero leads to a neutral plane brightness Changes the brightness Negative values result in a darker image Positive values increase the image s brightness saturation Changes the color saturation Negative values result in complementary colors by inverting the a b channels Higher absolute values increase color saturation lower absolute values reduce color saturation A value of zero leads to a desaturated black amp white image Examples The original image already heavily processed The boat is almost a silhouette TET s Bilateral blur with high radius Desaturated inverted radius and with high contrast soften with bilateral fiter contrast 2 50 brightness 0 00 saturation i 0 00 blend uniformly Y blend mode vividlight opacity 22 Intermediate result after lowpass Filter 109 3 4 5 9
8. ception it will return t rue plus any result returned by the Function if there is an exception it will return false and the error message of the exception We simply test these results and print them on the console 8 1 5 Exporting images with Lua 156 We have learned to use lua to adapt darktable to our particular workflow let s look at how to use lua to easily export images Darktable can easily export images to quite a Few online services but there are always more IF you are able to upload an image to a service via the command line then you can use lua to integrate it into darktable s user interface In this next example we will use lua to export via scp A new storage will appear in darktable s UI which will export images to a remote target via ssh s copy mechanism darktable require darktable darktable preferences register scp_export export_path WSstring y target SCP path Complete path to copy to Can include user and hostname darktable register_storage scp_export Export via scp function storage image format filename number total high_gquality extra data it coroutine yield RUN_COMMAND scp filename darktable preferences read scp_export export_path string then darktabpe print_error scp failed for tostring image end end darktable preferences register will add anew preference to darktable s prefer ence menu scp_export and export_path allow us to uniquely i
9. env LANG C gphoto2 auto detect 2 Verify camera driver abilities Execute the Following command and verify that the capture choices ability supports Image and configuration support is yes darktable will check these two abilities and decide if tethered shoot button should be shown or not env LANG C gphoto2 port usb abilities 3 Verify camera remote capture This step will verify that your camera can be remotely controlled that it can capture an image download it to your computer and display it within darktable env LANG C gphoto2 port usb capture image and download 4 Verify camera tethered capture And this last step tests if your camera supports events which darktable heavily relies on Running this command will make the gphoto2 process wait for an image capture event which you must manually trigger on your camera IF successful the image will be downloaded to your computer env LANG C gphoto2 port usb capture tethered 4 4 2 So now what IF any of the steps above Failed there are problems with your specific camera and driver Please report the issues to gphoto2 mailing list for Further help You can find the mailing list at www gphoto org http www gphoto org mailinglists Add the Following flags to the Failed command above for better support and attach the log output to your mail debug debug file gphoto2_debug log IF you successfully went through all the tests above your camera
10. rounding into account This is generally faster than local tonemapping as implemented in the tonemapping module but might lead to less convincing results with very high dynamic scenes As an enhancement to the original operators darktable can preserve detail of the input image and transfer it back to the output image operator bias target Reinhard Filmic and Drago global tonemap operators are available for use Depending on the selected operator different parameters can be adjusted Some operators are fully self adjusting and do not require specific controls Only offered for the Drago operator This parameter influences the contrast of the output image It is an essential parameter for adjusting the compression of high values and the visibility of details in dark areas According to the original paper a value of 0 85 is recom mended as a starting point Only offered for the Drago operator This is a scale factor to adjust the global image bright ness to the brightness of the intended display It is measured in cd m and should match the according value of your output device Higher values lead to a brighter image while lower values lead to a darker image detail Offered as an addition to all operators This parameter controls how much detail is pre served and transferred back into the output image after tonemapping 3 4 3 Color group Modules for working specifically on your image s color are found here in the color
11. 84 color mapping 112 color zones 86 colorize 112 contrast brightness saturation 70 crop and rotate 65 defringe 100 demosaic 71 denoise bilateral 93 denoise non local means 93 denoise profiled 92 dithering 97 equalizer 90 exposure 69 Fill light 74 Framing 102 global tonemap 80 graduated density 114 grain 107 highlight reconstruction 72 highpass 108 hotpixels 99 input color profile 88 invert 74 lens correction 94 levels 75 local contrast 79 lowlight 110 lowpass 108 monochrome 85 orientation 66 output color profile 82 raw denoise 97 rotate pixels 96 scale pixels 95 shadows and highlights 67 Sharpen 90 soften 106 splittoning 104 spot removal 96 tone curve 6 tonemapping 79 unbreak input profile 89 velvia 81 vibrance 88 vignetting 105 watermark 101 white balance 73 zone system 8 monitor profile 84 monochrome 85 more modules 62 move images 27 multiple instances 42 N Navigation 57 noise removal see denoise O OpenCL 219 orientation 67 output color profile 83 overexposed warning 63 overlay 14 P panoramas 218 path 49 pixelpipe 39 Preface vii preferences and settings 137 core options 141 GUI options 138 presets 148 session options 143 shortcuts 145 presets 148 module presets 41 program invocation 3 purple fringing 100 R recently used collections 26 red eye removal 120 remove images 27 rotate pixe
12. Available address SP aCe cc sect iat ans cunseatatasin sce uedsdeceestarasendeadtacesae des 216 91 3 Memon FragMmentaci ON awucmsteuietenwvesetoiiontastascetasderaiedtantone 216 OAC PUPEMEE limitations sietan terna A 217 9 1 5 Setting up darktable on 32 bit systems cece ccc eececeeceeceseeceeenees 217 9 1 6 darktable on 64 bit systems cee cececcecsececceccecsceseeceseesescescesees 218 9 2 Galkta DIG AMG O POM Ck it yi is eesti a a sigh a A sic es kts 219 D7 Nis PME Dac koro Un saissataaccharsasiass a a N 219 9 22 HOW OPENCLAWORKS aroia a r A Naa 219 9 2 3 How to activate OpenCL in darktable oo ee ceceseececeeeseseeens 219 9 2 4 Setting up OpenCL on your system secssessesssssessosssesseeseeseeeseeseesee 220 9 2 5 Possible problems and solutions sssesssesesessssesesesesssessesesesesesseses 221 9 2 6 Setting up OpenCL for AMD ATI devices cccceceececeecesceseeceeeeses 222 9 2 7 OpenCL performance optimization s sesssesessesesesesseresesesesesese 223 9 2 8 Multiple OpenCL devices osenesesesesessssesesesessssesesesesessesesesesesesee 225 9 2 9 OpenCL still does not run for Me eesssssssessssesesesesesssssseseseseseesesee 227 INGEN enaa a A A 229 vi Preface to this manual User manual version and applicable darktable version are listed below version date user manual 1 6 0 November 2014 darktable 1 6 November 2014 Translations of this manual to local languag
13. Input colors with a saturation that exceeds the permissible range of the selected profile get clipped to a maximum value linear Rec2020 RGB and Adobe RGB compatible allow for a broader range of unclipped colors while SRGB and linear Rec709 RGB produce a tighter clipping You should select the profile that prevents artifacts while still maintaining highest color dynamics Examples Close up of a blue light source LED with gamut clip ping off The activated levels module produces a ring of black pixel artifacts The same image and processing with gamut clipping set to linear Rec2020 RGB 3 4 3 11 Unbreak input profile Overview Usage linear This module adds a correction curve to image data E unbreak input profile which is required if you have selected certain input profiles in module input color profile IF you decide in module input color profile to use an ICC profile from the camera manu facturer a correction curve very Frequently needs to be pre applied to image data or else the Final output looks much too dark This extra processing is not required if you use darktable s standard or enhanced color matrices The correction curve is defined with a linear part extending from the shadows to some upper limit and a gamma curve covering mid tones and highlights For Further reading please also have a look at darktable s neigh bouring project UFRaw http ufraw sourceforge net
14. The masks manager panel is the central place where you manage all masks and shapes within the context of the current image Here you create delete and change shapes or give them unique names You can add shapes to and remove shapes from a mask and you define how multiple shapes interact within a mask 3 3 5 2 Usage In the top line of the masks manager panel you find buttons to create new shapes They are the same as in the drawn mask GUI see Section 3 2 7 Drawn mask for more details The lines below list all masks used and all individual shapes defined The masks are noted with a headline in the form grp levels indicating the module in which they are used The list of masks is Followed by a list of all individual shapes which have been generated in the context of the given image If a shape is in use by any of the masks it is marked by the symbol to the right of the shape name 3 3 5 3 Shapes By default shapes receive an automatically generated name consisting of the shape type brush circle ellipse path gradient and a number that is incremented automat ically You can replace these automatically generated names by more meaningful ones Double clicking on the existing shape name prompts you for a new one Giving a mean ingful name is a good habit especially if you are going to use the same selection in differ ent masks A name like house front makes it easier to get the right
15. The name of the input File to export lt xmp file gt The optional name of an XMP sidecar File containing the history stack data to be ap plied during export IF this option is not given darktable will search For an XMP file that belongs to the given input file lt output File gt The name of the output file darktable derives the export file format From the file extension width lt max width gt This optional parameter allows to limit the width of the exported image to that num ber of pixels height lt max height gt This optional parameter allows to limit the height of the exported image to that num ber of pixels bpp lt bpp gt An optional parameter to define the bit depth of the exported image allowed values depend on the file format Currently this option is not yet Functional IF you need to define the bit depth you need to use the Following workaround COre conf plugins imageio format lt FORMAT gt bpp lt VALUE gt where lt FORMAT gt is the name of the selected output format hg lt 0 1 true False gt A flag that defines whether to use high quality resampling during export see Sec tion 7 2 Core options Defaults to true verbose Enables verbose output core lt darktable options gt All command line parameters following core are passed to the darktable core and handled as standard parameters See Section 1 1 1 darktable binary for a detailed description 1 2
16. The source image taken shortly after sunset under Front lighting conditions The target image taken in the afternoon with a part ly clouded sky Our goal is to transfer the evening at mosphere of the source image The target image with color mapping applied A num ber of 2 clusters was used color dominance is set to 100 for a bold but still credible effect histogram equalization is set to 80 3 4 5 13 Graduated Density Overview v This module aims at simulating a graduated density DEEE graduated density filter in order to correct exposure and color in a pro density 00 compression gressive manner Base hue Saturation blend Usage The module uses a gradient to modify the exposure and the color cast of the image ina non homogeneously manner This module is known to provoke banding artifacts under certain conditions you should consider to activate the dithering module see Section 3 4 4 11 Dithering 114 density Set the density of the filter in ev A low value underexposes slightly whereas a high value creates a strong filter It is expressed as ev that is equivalent to f stops Lens Filters are often referred as ND2 ND4 ND8 and so on Each time you add an ev you double the ND So ND2 is 1 ev ND4 is 2 ev and so on You can also express it in optical density or transmittance The table below sums up the different approach for the most common filters ND ev or F
17. To deactivate all snapshot you need to call this Function on the active snapshot self types dt_lua_snapshot_t The snapshot to activate types dt_lua_snapshot_t name String The name of the snapshot as seen in the UI 8 2 2 28 types hint_t enum a hint on the way to encode a webp image Attributes e values e hint_default e hint_picture e hint_photo e hint_graphic 8 2 2 29 types snapshot_direction_t enum Which part of the main window is occupied by a snapshot Attributes e values e left e right e top e bottom 8 2 2 30 types dt_imageio_j2k_format_t enum J2K format type Attributes e values j2k 207 e jp2 8 2 2 31 types dt_imageio_j2k_preset_t enum J2K preset type Attributes e values e off e cinema2k_24 e cinema2k_48 e cinema4k_24 8 2 2 32 types yield_type enum What type of event to wait for Attributes e values e WAIT_MS e FILE READABLE e RUN_COMMAND 8 2 2 33 types comp_type_t enum Type of compression for webp Attributes e values e webp _ lossy e webp lossless 8 2 2 34 types lua_pref_type enum The type of value to save in a preference Attributes e values e string e bool e integer 208 e Float e file e directory e enum 8 2 2 35 types dt_imageio_exr_compression_t enum undocumented types dt_imageio_exr_compression_t Attributes e values e off e rle e ZIpS e Zip e piz e pxr24 b44 e b44a 8 2 3 events This section do
18. When backing up your RAWs make sure to also save the XMP files Physically delete selected images From Filesystem See also preference option ask before erasing images from disk Section 7 1 GUI options IF this configuration option is not active darktable will delete the file s without Further question This is irreversible and will also erase your development work of these images When deleting an image with duplicates darktable keeps the original input File on disk until the last of the duplicates gets deleted Physically move selected images parent file plus all accompanying XMP sidecar files to another Filesystem folder darktable does not overwrite images in the target folder IF an input image with the given Filename already exists in the target Folder the source image is not moved but kept where it is Physically copy selected images parent File plus accompanying XMP sidecar File to anoth er Filesystem folder IF an image with the given name already exists in the target Folder it does not get overwritten instead a new duplicate with the given history stack is gen erated create hdr 27 Create a high dynamic range image from the selected images and store it as anew source File in DNG format Images need to be properly aligned which implies that they have been taken on a sturdy tripod You can also generate HDRs with programs like Luminance HDR http qtpFsgui sourceforge net and later import them into
19. a reasonable starting point However as your devices might have quite different levels of processing power it makes sense to invest a Few thoughts and optimize your priority list Here is an example Let s assume we have a system with two devices a fast Radeon HD7950 and an older and slower GeForce GTS450 darktable started with darktable d opencl will report the Following devices opencl_init successfully initialized opencl_init here are the internal numbers and names of OpenCL devices available to darktable opencl_init O GeForce GTS 450 opencl_init lt Ta tae opencl_init FINALLY opencl is AVAILABLE on this system So the GeForce GTS 450 is detected as the first device the Radeon HD7950 Tahiti as the second one This order will normally not change unless the hardware or driver config uration is modified But it s better to use device names rather than numbers to be on the safe side As the GTS450 is slower than the HD7950 an optimized opencl_device_priority could look like GeForce GTS450 Tahiti Tahiti Tahiti The GTS450 is explicitly excluded from doing the center image pixelpipe this is reserved to all other devices i e the HD7950 Tahiti Completely the opposite for our preview pixelpipe Here the Tahiti is excluded so that only the GTS450 will be allowed to do the work For file export and thumbnail generation we want all hands on deck However darktable should First lo
20. acts as a view for the exposure module You can activate multiple instances of this module each with different parameters acting on different parts of the image which you select by a drawn mask see Section 3 2 4 Mul tiple instances and Section 3 2 7 Drawn mask The histogram is always linked to the lowest instance in pixelpipe This module is responsible for one of the most basic steps in each raw image development An exposure adjustment value allows you within certain limits to correct for under or overexposure A shift by 1EV is equivalent to a change of exposure time by a factor of 2 Positive exposure corrections will make the image brighter As a side effect noise level gets higher Depending on the basic noise level of your camera and the ISO value of your image positive exposure compensations with up to 1EV or 2EV still give reasonable re sults Negative exposure corrections will make the image darker Given the nature of digital im ages this can not correct for Fully blown out highlights but allows to reconstruct data in case that only some of the RGB channels are clipped see also Section 3 4 1 8 Highlight reconstruction A black level adjustment is a basic tool to increase contrast and pop of an image The value defines at what threshold dark gray values are cut off to pure black Use with care as the clipped values can not be recovered in other modules Further down the pixelpipe Please also ha
21. cachedir lt user cache directory gt localedir lt locale directory gt luacmd lt lua command gt conf lt key gt lt value gt All parameters are optional in most cases users will start darktable without any additional parameters in which case darktable uses suitable defaults d This option enables debug output to the terminal There are several subsystems of darktable and debugging of each of them can be activated separately You can use this option multiple times if you want debugging output of more than one subsystem IMG_1234 RAW image _Folder You may optionally supply the Filename of an image or the name of a folder contain ing image files IF a Filename is given darktable starts in darkroom view with that file opened If a Folder is given darktable starts in lighttable view with the content of that Folder as the current collection version This option causes darktable to print its version number a copyright notice some oth er useful information and then terminate disable opencl This option prevents darktable From initializing the OpenCL subsystem Use this op tion in case darktable crashes at startup due to a defective OpenCL implementation library lt library file gt darktable keeps image information in an sqlite database for Fast access The default location of that database file is SHOME config darktable library db You may give an alternative location e g if you want to do some
22. darktable preferences read FUME ort SCOTT E GEL Name SErLaG type types lua_pref_type depends on type Reads a value from a Lua preference script SEE LRG Invisible prefix to guarantee unicity of preferences name String The name of the preference displayed in the preference screen type types lua_pref_type The type of the preference return depends on type The value of the preference darktable preferences write function SCLIPE SUCLNG name string 181 type types lua_pref_type value depends on type Writes a value to a Lua preference script Sering Invisible prefix to guarantee unicity of preferences name String The name of the preference displayed in the preference screen type types lua_pref_type The type of the preference value depends on type The value to set the preference to 8 2 1 12 darktable styles This pseudo table allows you to access and manipulate styles darktable styles types dt_style_t Each existing style has a numeric index you can iterate them using ipairs darktable styles create Tune Lon image types dt_lua_image_t name string description string types dt_style_t Create a new style based on an image image types dt_lua_image_t The image to create the style From name St RLiaG 182 The name to give to the new style description Striag The description of the new style return types dt_style_t The new style object dar
23. exif_ model 190 expandable 205 expanded 205 export 174 184 203 extension 195 extra registration parameters 210 210 211 212 212 213 213 Filename 189 201 201 202 206 Film 189 Films 164 Filmstrip 171 Filter 172 Find 176 Format 198 geotagging 172 get_group_members 194 get_tags 1 7 188 global_toolbox 172 global_toolbox grouping_toggle 212 global_toolbox overlay_toggle 213 green 192 grouping 172 group leader 194 group_with 193 gui 166 has_gui 178 has_tostring 213 height 192 199 hint 198 hinter 171 hint_t 207 histogram 174 history 174 hovered 166 id 189 202 204 206 image 173 implicit_yield 213 import 172 184 185 intermediate export image 209 is hdr 192 is_ldr 192 IS raw 192 known 188 latitude 168 191 libs 169 lighttable 169 lighttable_mode 173 live view 175 local_copy 194 location 175 longitude 168 191 lua_pref_type 208 make group leader 193 map 168 map_settings 175 masks 174 max_depth 187 max_height 195 max snapshot 170 max_width 195 metadata 171 metadata_view 170 mime 195 modulegroups 173 modulelist 171 module toolbox 174 move 189 move_image 186 202 name 195 199 203 204 204 204 206 207 navigation 174 new 164 new_format 165 new_storage 166 num 204 on_screen 205 parent 213 231 path 189 202 percent 206 plugin _name 195 199 post import film 211 post import i
24. gnetting softening etc see Section 3 4 5 Effect group Clicking on one of the group symbols will show the modules in that group IF you once again click on the symbol grouping will be de activated and all non hidden modules will be shown in one long list This list shows the sequence in which modules are applied From bot tom to top As a general principle darktable applies modules in a pre defined sequence 3 3 8 More modules 62 More modules at the bottom of the right panel is more modules used to show the less Frequently used modules By default only standard modules are shown to the user but you can use this Function to make the extra mod ules visible or alternatively to hide away modules you don t typically use Each module is shown with a small icon next to its name Left click with your mouse to toggle the status between visible hidden and Favorite Favorite modules are indicated by a star in Front of the icon and in addition to appearing in their normal module group will also be visible in the module group favorites This is a good way to get fast access to modules that you use very Frequently Visible modules are indicated in the list by a light grey background whilst hidden modules have a dark grey background and do not display any of their controls Hiding or un hiding modules is not meant to be part of your daily workflow you should only occasionally need to review the modules you typically use 3 3 9 B
25. mixer 1 Activate the channel mixer module 2 Select the gray output channel 3 Set the proportion of each color the sum having to equal 1 if you want to keep your global lightness 117 3 5 2 Cross processing 3 5 2 1 Overview Cross processing is a analog processing technique where slide film normally developed thanks to an E6 solution is processed in chemicals used for process ing print Film C41 The resulting images get skewed colors usually a cyan hue and increased contrast and saturation The standard way for doing digital cross processing is to use a channel curve tool but dark table lacks this tool for the moment and another way to accomodate the effect is used 3 5 2 2 Procedure 118 This procedure uses tone curve channel mixer and splittoning modules 1 Image preparation Prepare the image for the cross process steps by adjusting the base settings such as exposure whitebalance etc for a correctly looking image 2 Boost contrast Select the medium contrast curve preset for tone curve module Section 3 4 2 3 Tone curve to boost the overall contrast in the image You might later return here to tune the curve for better result 3 Color cast This step changes the color cast as the base for the effect using the channel mixer mod ule Section 3 4 3 2 Channel mixer You might later again return to this and Finetune the colorcast of the Final result a Enable the channel mixer
26. revise the rating at any time You can also mark an image as rejected by pressing the icon or typing the rkey This will remove all stars You can reverse the rejection by applying a new star rating There are several ways to change a rating While hovering the cursor over an image thumb nail you can press a number key 0 5for the number of stars or type rto reject an image this is probably the Fastest way when rating your images on first inspection of a Film roll You can also directly click on the stars displayed in the thumbnails click the xto reject click the Fifth star to get a rating of five stars etc Clicking either the x 17 or the First star for a second time resets the image rating to unranked or zero stars To rate one or more images at once select those im ages see Section 2 3 5 Select and then press the key for your rating or click the desired star rating in the bottom panel of the lighttable view Color labels are another way to sort images and can be used as an alternative to star ratings or work alongside star ratings Each image can carry any combination of one or more color labels in red yellow green blue and purple You can set the color labels for a single image by hovering your cursor over the thumbnail and pressing the Function keys F7 F5 which correspond with the labels in the order given above To toggle the color labels of one or more images se lect the desired ima
27. saturation boost on shadows similar to the one you would also expect in nature if shad ows would receive more light highlights color adjustment This slider controls the color saturation adjustment made to highlights high values cause saturation enhancements on darkened highlights low values cause desaturation on dark ened highlights Often highlights do not contain enough color information to give con vincing colors when darkened You might need to play a bit with this parameter in order to Find the best Fitting value depending on your specific image but be aware that sometimes results still might not be Fully satisfying Examples 68 Original image exposed for the outer sunlit wall to avoid clipped highlights As a consequence the inte rior of the barn has pitch black shadows O Seer Shadows get lightened highlights are untouched ters overall effect toned down a bit by blend mode nor mal and an opacity of 65 soften with gaussian 100 00 25 00 ERIE compress 20 00 b shadows color adjustment highlights color adjustment blend mode opacity blend uniformly Resulting image j au de Y x Gees sates i m ii k 3 EEP SEA s EAEN n 3 4 1 4 Base curve Overview Usage scale Camera sensors provide data in linear RGB format the original image appears flat and dull That s the reason why camera manufacturers apply their char acteristic b
28. table storing a history stack as a style and apply ing it to other images Styles are created within this cross process panel or in the darkroom see Section 3 3 3 History sopis suppress color blotches stack They are managed within this lighttable pan el which allows you to create apply edit and delete styles create duplicate create import 2 3 8 1 Usage This panel displays a list of all available styles A search Field above the list allows you to input a text string which is compared against the styles names and descriptions thus limiting the list to the matching ones Double clicking on a style name applies the style to all selected images create duplicate When applying a style to selected images activating this box creates a duplicate of the image before applying the style Disable this option if you want to try various styles with out creating multiple duplicates beware that in this case any existing history stack gets overwritten and cannot be recovered create This creates new styles out of the history stacks of the selected images For each image a style creation window pops up You need to supply a unique name for the new style and you can add an additional descriptive text You have the option to de select those history stack items which you want to not be part of the newly created style edit Styles are collections of history stack items After pressing edit you are prompted with a d
29. BackSpace O lt Primary gt f lt Alt gt 1 lt Alt gt 2 lt Alt gt 3 lt Primary gt r lt Primary gt z lt Primary gt f lt Primary gt c lt Primary gt lt ShiFt gt c lt Primary gt v lt Primary gt lt ShiFt gt v lt Primary gt e F1 F2 F3 F4 F5 lt Primary gt d lt Primary gt lt Shift gt c lt Primary gt c lt Primary gt lt Shift gt v lt Primary gt v OA WN lt darktable gt modules image group lt darktable gt modules image ungroup lt darktable gt modules image remove from collection lt darktable gt modules lighttable_mode zoom max lt darktable gt modules lighttable_mode zoom in lt darktable gt modules lighttable_mode zoom out lt darktable gt modules lighttable_mode zoom min lt darktable gt modules live_view toggle live view lt darktable gt modules select select all lt darktable gt modules select invert selection lt darktable gt modules select select none lt darktable gt modules tagging tag lt darktable gt image operations clipping commit lt darktable gt image operations colorout toggle gamutcheck lt darktable gt image operations colorout toggle softproofing lt darktable gt image operations Flip rotate 90 degrees ccw lt darktable gt image operations flip rotate 90 degrees cw lt Primary gt g lt Primary gt lt ShiFt gt g Delete lt Alt gt 1 lt Alt gt 2 lt Alt gt 3 lt Alt gt 4 v lt Primary gt a lt Primary gt i lt Primary gt lt Shift gt a lt Primar
30. Section 2 2 6 Image grouping 2 3 7 History stack This panel allows manipulating the history stack de history stack velopment of images For each image development copy copy ai chard is written in a sidecar file xmp and is Fully non de z aa Rae structive A load sidecar file write sidecar files 2 3 1 Usage copy 28 Copy the history stack of the selected image You will be prompted for which items are to be include IF more than one image is selected the history stack is taken from the image that has been selected first copy all Copy the complete history stack of the First selected image all items will be included IF more than one image is selected the history stack is taken From the image that has been selected First discard Physically delete the history stack of the selected images Beware this action can not be undone overwrite append This setting defines how a new history stack behaves when pasted on an image that al ready has a history stack Overwrite will delete the previous history stack whereas ap pend will concatenate the two history stacks Caution only in append mode you keep the option to later reconstruct your existing history stack whereas in overwrite mode your previous edit gets irrevocably lost Beware the set ting of this parameter remains effective when you quit darktable paste Paste a previously copied history stack onto all s
31. Set the upper limit for the region counted as shadows and where no gamma correction is performed Typically values between 0 0 and 0 1 are required by the profile 89 gamma Set the gamma value to compensate your input profile Often the required value is 0 45 the reciprocal of 2 2 gamma used by some manufacturer s profile 3 4 4 Correction group The correction group contains the modules that will correct typical problems in an photo such as hotpixels spot removal noise lens correction among others This group also in cludes the basic sharpening tools 3 4 4 1 Sharpen Overview This is an standard UnSharp Mask USM tool for sharpening the details of an image radius amount thi eshold blend Usage This module works by enhancing the contrast around edges and thereby enhances the impression of sharpness of an image In darktable this module is only applied to the L channel in Lab color space radius USM applies a gaussian blur to your image as part of its algorithm This controls the blur radius which in turn defines the spatial extent of edge enhancement Too high values will lead to ugly over sharpening amount This controls the strength of the sharpening threshold Contrast differences below this threshold are excluded from sharpening Use this to avoid amplification of noise 3 4 4 2 Equalizer Overview 90 This versatile module can be used to achieve a variety of effects such as bloom de
32. The grad uated density Filter adds a neutral or colored gradient to your image for exposure and col or correction 1 3 3 Exporting images 10 Changes to an image are not saved as in a regular image editor darktable is a non destruc tive editor which means all changes are stored in a database and the original image is untouched Therefore you need to export images to bake the processing options into an output File that can be distributed outside of darktable Images are exported from the lighttable view using the export selected dialog in the right panel Section 2 3 12 Export selected In general export means save my developed RAW image as a JPEG The export is modularized into storage and format darktable ships with several storage modules such as save on disk various webalbums a LaTeX photo book template and more Format modules are the actual image formats such as JPEG PNG TIFF OpenEXR and more Select images on the lighttable choose the target storage and Format and set the maxi mum width and height image restraints This means that none of the images will be bigger than any of the width height restraints and hit the export button Leave the width and height restraints at zero if you want the original resolution 11 12 Chapter 2 Lighttable The lighttable is where you manage all your images ratings export and much more 2 1 Overview 14 In the central view your images are shown as thu
33. a consequence the histogram which is derived From the navigation window will show this increased num ber of levels and is no longer a Full match of the output image method This combobox sets the dithering method Floyd Steinberg error diffusion with some typical output bit depths and random noise dithering are both supported Floyd Stein berg systematically distributes quantization errors over neighboring pixels whereas ran dom dithering just adds some level of randomness to break sharp tonal value bands The default setting is Floyd steinberg auto which automatically adapts to the desired out put format damping This slider is only displayed if you choose method random It controls the level of added random noise expressed as a damping Factor in a 10 log gt basis A value of 80 is a good Fit For 8 bit output Formats and 160 for 16 bit ones Examples 98 The visibility of the following examples depends on the quality of your monitor or the print quality Banding artifact caused by vignetting 100 crop of a 8 bit PNG effect heavily exaggerated by strong contrast enhancement The same image area processed as above but with activated Floyd Steinberg dithering 3 4 4 12 Hotpixels Overview This module is able to automatically detect and elim inate hotpixels Hotpixels are pixels which Failed to record light level correctly Detected hotpixels are replaced by an average value of t
34. above but with 25 satu ration 3 4 5 6 Grain 107 Overview v This module is an artistic Feature which simulates the 2008 grain 400150 grain of a film coarseness strength blend off Y Usage The grain is processed on the L channel from CIELAB coarseness Set the grain size which has been scaled to simulate an ISO number strength Set the strength of the effect 3 4 5 7 Highpass Overview Highpass acts as a high pass Filter The primary usage 2068 highpass v For this filter is in combination with a blending op sharpness _ i erator Try out blend mode soft light to get high on a pass sharpening Use the opacity slider to adjust the aur strength of the effect or use a drawn mask see Sec tion 3 2 7 Drawn mask or parametric mask see Section 3 2 8 Parametric mask to limit the effect to only parts of your image Usage sharpen Set the sharpness The higher the more details contrast boost Set the contrast boost 3 4 5 8 Lowpass Overview A lowpass filter eg gaussian blur with additional DRE uaa control of the outcome both of contrast and satura ragius sp tion The primary usage For lowpass filter is in com seed i gaussian 7 bination with a blending operator see Section 3 2 6 brightness a Blending operators Try out the preset named lo saturation 1 00 cal contrast mask with an overlay blending opera tion contrast re 1 00 blend rh Usage
35. be shifted independently until the result matches your expectations An arrow helps to tell source from target area Use the shape specific controls to adjust its size its border width and other attributes Right click on a shape to delete it Collapse the module to complete the changes Examples Let s use this portrait as example we want to remove some dirt and unwanted catchlight From camera pop up strobe have marked all the spots that want to remove From the image with circle shapes and appropriately selected source areas And here is the result image of the spotremoval 3 4 4 10 Raw denoise Overview v Raw denoise allows you to perform denoising on 00 raw denoise pre demosaic data It is ported from dcraw http noise threshold 0 010 www cybercom net dcoffin dcraw blend Usage noise threshold Set the threshold for noise detection Higher values lead to stronger noise removal and higher loss of image detail 3 4 4 11 Dithering Overview This module eliminates some of the typical banding O O dithering Y artifacts which can occur when darktable s internal floyd steinberg auto 7 32 bit floating point data are transferred into a dis crete 8 bit or 16 bit integer output format for display or file export Banding is a problem which can arise when an image is downsampled into a lower bit depth Downsampling happens regularly when darktable displays or exports the results of a pixelp
36. cache In the long run however this is all the memory that s ever going to be allocated for thumbnails So if we can successfully grab this portion once we are relieving a lot of pressure on fragmentation For long sessions 9 1 6 darktable on 64 bit systems 218 There s not much to be said here Of course also 64 bit systems require a sufficient amount of main memory so the 4GB plus swap recommendation holds true On the other hand 64 bit architectures do not suffer from the specific 32 bit limitations like small address space and fragmentation madness Most modern Intel or AMD 64 bit CPUs will have available address space in the range of several Terabytes The word modern is relative in this context all AMD and Intel CPUs introduced since 2003 and 2004 respectively offer a 64 bit mode Linux 64 bit has been available for many years All relevant Linux distributions give you the choice to install a 32 bit or a 64 bit version with no added costs You can even run old 32 bit binaries on a 64 bit Linux The only thing you need to do invest some time into the migration In the end we strongly recommend moving to a 64 bit version of Linux There really is no reason not to upgrade to 64 bit Ona 64 bit system you can safely leave the tiling related configuration parameters at their defaults host memory limit in MB For tiling should have a value of 1500 and minimum amount of memory in MB for a single buffer in tiling sho
37. cases You can create local copies of selected pictures on your computer s local drive This local copy is then used when the original image file is not accessible At a later point when connected again with your main storage medium you can synchronize the XMP sidecar Files deleting the local copy of your input image These operations can be found in the selected images panel see Section 2 3 6 Selected image s For safety reasons if local copies exist and the external storage is available the local XMP sidecars are automatically synchronized at start up The local copies are stored into the SHOME cache darktable directory and named img lt N gt lt SIGNATURE gt lt EXT gt where N is the image number in darktable SIGNATURE is a hash signature SHA 1 of the Full pathname EXT is the original Filename extension A local copy is identified in the lighttable view with a white marker on the right of the thumbnail In addi tion all local copies carry the darktable local copy tag For selecting them easily 21 2 3 Lighttable panels 2 3 1 Import This panel is for importing images into film rolls import You can either import a complete folder by pressing image Folder or a single image with image You can also folder cause darktable to search for connected cameras by scan for devices pressing scan for devices IF a supported camera is connected you can import directly From that cam
38. consider activating this module late in your workflow patch size The radius of the patch for similarity evaluation strength The strength of the denoise Higher values lead to a stronger effect luma Amount of denoise to apply to luma Select carefully in order not to lose too much struc ture chroma Amount of denoise to apply to chroma You can be much more aggressive with this para meter compared to luma 3 4 4 5 Denoise bilateral Overview Usage This module is used to denoise high ISO pictures 2008 denoise non local means Y It is Flagged as a slow module due to its high re patch size 2 strength source consumption both in terms of CPU cycles and in terms of memory usage Quite counter intuitive chroma ly the greater the values for sliders the lesser re blend sources This module reduces noise in your image but preserves sharp edges This is accomplished by averaging pixels with their neighbors taking into account not only the geometric dis 93 radius red green blue tance but also the distance on the range scale i e differences in the RGB values As de noising is a resource hungry process it slows down pixelpipe processing significantly con sider to activate this module late in your workflow Set the spatial extent of the gaussian blur Blur intensity for red channel Blur intensity for green channel Blur intensity for blue channel 3 4 4 6 Lens correction Over
39. curve levels and zone system modules see Section 3 4 2 3 Tone curve Section 3 4 2 2 Lev els and Section 3 4 2 4 Zone system Likewise you may adjust color saturation in a more detailed way with the tone curve color contrast and color zones modules see Sec tion 3 4 2 3 Tone curve Section 3 4 3 4 Color contrast and Section 3 4 3 7 Color zones contrast This slider adjusts the image s contrast brightness This slider adjusts the image s brightness saturation This slider adjusts the color saturation 3 4 1 7 Demosaic Overview Usage This module allows you to control how the demosaic 0 demosaic Y iS processed method PPG fast Y edge threshold 0 000 gag color smoothing off Y match greens disabled Y Demosaic is an essential step of any raw image development process A detailed description would be beyond the scope of this manual In a nutshell the sen sor cells of a digital camera are only able to record different levels of lightness not dif ferent color In order to get a color image each cell is covered by a color filter either in red green or blue Due to the color sensitivity of the human vision there are two times more green cells than red or blue Filters are arranged in a certain mosaic called Bayer pattern Therefore each pixel of your image originally only has information about one col or channel Demosaic reconstructs the missing color channels by i
40. darktable for Further pro cessing see Section 2 3 1 3 Supported file Formats Note that darktable cannot cur rently create HDR files from images made with non Bayer e g Fujifilm X Trans sensors duplicate rotation Create a virtual copy of selected images within darktable It allows testing different de velopments for the same image for example Duplicate images share the same parent input File but each have their own XMP sidecar File Perform a counter clockwise or clockwise rotation on selected images The third button resets the image rotation to the value in the EXIF data This Feature is directly linked to the orientation module see Section 3 4 1 2 Orientation adjustments are converted into history stack items of that module copy locally This action will create local copies of the selected images into the local drive These copies will then be used when the original images are not accessible see Section 2 2 9 Local copies resync local copy group ungroup This action will synchronize the XMP sidecars of the temporary local copy and the copy in external storage if needed and will remove the local copies Note that if a local copy has been modified and the external storage is not accessible the local copy won t be deleted see Section 2 2 9 Local copies Create a new group from selected images see Section 2 2 6 Image grouping Remove selected images from the group see
41. debug 187 187 delete 165 176 183 187 193 202 203 204 description 190 203 detach 177 204 detach_tag 188 direction 170 drop_cache 194 dt_imageio_exr_compression_t 209 dt_imageio j2k_ format_t 207 dt_imageio j2k_preset_t 208 dt_imageio_ module format_data copy 197 dt_imageio_ module format_data_exr 196 dt_imageio_ module format_data j2k 198 dt_imageio_ module format_data jpeg 197 dt_imageio_ module _format_data_pfm 197 dt_imageio_ module _format_data_png 196 dt_imageio_ module _format_data_ ppm 197 dt_imageio_ module format_data_tiff 196 dt_imageio_ module _format_data_webp 197 dt_imageio_ module format_t 195 dt_imageio_module_ storage _data_ disk 201 dt_imageio_module_ storage data email 200 dt_imageio_module_ storage data facebook 200 dt_imageio_module_ storage data flickr 200 dt_imageio_module_ storage data gallery 201 dt_imageio_module_ storage data latex 200 dt_imageio_module_ storage _data_picasa 201 dt_imageio_module_ storage t 199 dt_lib_module_t 204 dt_lua_backgroundjob t 206 dt_lua_ film_t 202 dt_lua_ image _t 188 dt_lua_snapshot_t 206 dt_lua_ tag t 204 dt_style_item_t 203 dt_style_t 203 dt_view_t 205 dump 187 duplicate 183 185 189 203 duplicate index 189 events 209 exif_aperture 190 exif_crop 191 exif_datetime_taken 191 exif exposure 191 exif_ Focal_length 191 exif Focus distance 191 exif_iso 191 exif_lens 190 exif_maker 190
42. experiments without compromis ing your original library db If the database File does not exist darktable creates it For 3 you You may also give memory as a library File in which case the database is kept in system memory all changes are discarded when darktable terminates datadir lt data directory gt This option defines the directory where darktable finds its runtime data The default place depends on your installation Typical places are opt darktable share dark table and usr share darktable moduledir lt module directory gt darktable has a modular structure and organizes its modules as shared libraries for loading at runtime With this option you tell darktable where to look for its shared li braries The default place depends on your installation typical places are opt dark table lib64 darktable and usr lib64 darktable tmpdir lt tmp directory gt The place where darktable stores its temporary files IF this option is not supplied darktable uses the system default configdir lt config directory gt This option defines the directory where darktable stores the user specific configura tion The default place is SHOME config darktable cachedir lt cache directory gt darktable keeps a cache of image thumbnails for fast image preview and of pre compiled OpenCL binaries for fast startup By default the cache is located in SHOME cache darktable There may
43. exposed image of the ground A rather disturb ing element is the decay of brightness in the tree trunks from bottom to top darktable s graduated density filter together with the parametric mask feature see Section 3 2 8 Parametric mask comes in handy We can add a brightness gradient that is just inverted in relation to the hardware filter As we only want to compensate the unnatural decay of brightness in the tree trunks we combine the module with a suited blend mask The resulting image Tip IF you know you intend to use the graduated density filter before actually making a shot with your camera you might want to underexpose by one or two thirds of an f stop to make sure detail remains in the highlights When all detail has truly been blown out the graduated density filter cannot produce a pleasing results this is a limitation that is inherent to digital postprocessing For instructions on how to intentionally underexpose please consult your camera s manual look for exposure compensation 3 5 Examples 3 5 1 Converting to black and white 3 5 1 1 Overview Black and white conversion can be achieved in several ways with darktable Indeed darktable comes with a lot of modules especially For color manipulation In this manual I will show you 4 ways to perform a black and white conversion 3 5 1 2 The obvious way monochrome module To perform the conversion just activate the monochrome module Sectio
44. file will allow you to Fully restore your work default on store xmp tags in compressed format Entries in XMP tags can get rather large and may exceed the available space to store the history stack in output files This option allows binary XMP tags to be compressed in order ms to save space Available options are never always and only large entries default activate opencl support darktable can use your GPU to speed up processing significantly Interface OpenCL re quires suitable hardware and matching OpenCL drivers on your system IF one of those is not Found the option is greyed out Can be switched on and off at any time and takes immediate effect default on always try to use littlecms2 IF this option is activated darktable will use system library littlecms2 instead of its own routines This is about 28x slower than the default but might give more accurate results in some cases default off 141 do high quality resampling during export The image will First be processed in Full resolution and downscaled at the very end This can result in better quality sometimes but will always be slower default off demosaicing for zoomed out darkroom mode Interpolation when not viewing 1 1 in darkroom mode always bilinear Fast is Fastest but not as sharp at most ppg reasonable is using ppg interpolation modes specified below Full possibly slow will use exactly the settings for
45. group 3 4 3 1 Velvia Overview The velvia module enhances image saturation Its ef 2008 Fect is tailored to increases saturation less on lower strength saturated pixels than on highly saturated pixels blend Usage strength This slider controls the strength of the effect mid tones bias mid tones bias Velvia can reduce its effect for mid tones to avoid unnatural skin tones The mid tones bias slider controls this selectivity reducing its value reduces mid tone protection and makes the overall velvia effect stronger 3 4 3 2 Channel mixer Overview This module is a powerful tool to manage channels 2008 It accepts red green and blue channels as an input destination red As output it provides red green blue gray hue sat uration and lightness channels blue blend F v Usage First select your output channel and then set the amount each input channel feeds into that output channel Examples For skin tones the blue channel tends to represent detail with red tending to also have smoother tones than green Therefore tonal rendering is controlled by how we blend of the three input channels 81 Here a monochrome portrait is produced by simply selecting the grey channel as output A smooth skin tone is achieved by reducing the blue channels input and also emphasizing the red channels input relative to green An RGB mix of 0 9 0 3 0 3 was used togeth er with an 0 1 EV exposure increase
46. handles are used so we can monitor success failure of kernels and profiling info even if the pixelpipe is run asynchronously The number of event handles is a limited resource of your OpenCL driver For sure we can recycle them but there is a limited number that we can use at the same time Unfortunately there is no way to find out what the resource limits are so we need to guess Our default value of 25 is quite conservative You might want to try if higher values like 100 give better OpenCL per Formance IF your driver runs out of free handles you would experience Failing Open CL kernels with error code 5 CL_OUT_OF_RESOURCES or even crashes or system Freezes reduce the number again in that case A value of 0 will block darktable from using any event handles This will prevent darktable from properly monitoring the suc cess of your OpenCL kernels but saves some driver overhead The consequence is that any Failures will likely lead to garbled output without darktable taking notice only recommended if you know for sure that your system runs rock solid You can also set this parameter to 1 which means that darktable assumes no restriction in the num ber of event handles this is not recommended opencl_synch_cache This parameter if set to TRUE will force darktable to Fetch image buffers from your GPU after each module and store them in its pixelpipe cache This is a very resource consuming operation It only makes sense if you have a r
47. if the ISO value of your image lies within the given range exposure only apply the preset if the exposure time of your image lies within the given range set as the upper value to match arbitrarily long exposures aperture only apply the preset if the aperture of your image lies within the given range set F O as the lower value to match arbitrarily open apertures set F as the upper value to match arbitrarily closed apertures Focal length only apply the preset if the Focal length of your image lies within the given range from 0 to 1000 149 150 Chapter 8 Scripting with Lua darktable comes with a versatile scripting interface For Functionality enhancement dt require darktable dt register_storagelf module_stitcher mosaic generator nil function storage image _table end dt print_error Will try to stitch now command gm convert for _ v in pairs image_table do command command v end command command append resize 15 dt configuration tmp_dir dt print_error this is the command command os execute command dt print Stitching saved to dt configuration tmp_dir tmp png tmp png 151 8 1 Lua usage Lua can be used to define actions which darktable will perform whenever a specified event is triggered One example might be calling an external application during file export in order to apply additional processing steps outside of darktable
48. image back lt darktable gt views darkroom overexposed lt darktable gt views darkroom toggle Film strip lt darktable gt views darkroom zoom close up lt darktable gt views darkroom zoom fill lt darktable gt views darkroom zoom fit lt darktable gt views map redo lt darktable gt views map undo lt darktable gt views capture toggle Film strip lt darktable gt modules copy_history copy all lt darktable gt modules copy_history copy lt darktable gt modules copy_history paste all lt darktable gt modules copy_history paste lt darktable gt modules export export lt darktable gt modules filmstrip color red lt darktable gt modules filmstrip color yellow lt darktable gt modules filmstrip color green lt darktable gt modules filmstrip color blue lt darktable gt modules filmstrip color purple lt darktable gt modules filmstrip duplicate image lt darktable gt modules filmstrip copy history parts lt darktable gt modules filmstrip copy history lt darktable gt modules filmstrip paste history parts lt darktable gt modules filmstrip paste history lt darktable gt modules filmstrip rate 1 lt darktable gt modules filmstrip rate 2 lt darktable gt modules filmstrip rate 3 lt darktable gt modules filmstrip rate 4 lt darktable gt modules filmstrip rate 5 lt darktable gt modules filmstrip rate desert lt darktable gt modules filmstrip rate reject 0 r l apostrophe Down Left Right Up lt Primary gt e space
49. images that need correction by their EXIF data and automatically acti vates this module For other images the module always remains disabled The modules has no parameters 3 4 4 8 Rotate pixels Overview The sensors of some cameras like the Fujifilm FinePix 0 rotate pixels S2Pro F700 and E550 have a diagonally oriented automatic pixel rotation Bayer pattern instead of the usual orthogonal layout Without correction this would lead to a tilted image with black corners This module applies the needed rotation Usage darktable detects images that need correction by their EXIF data and automatically acti vates this module For other images the module always remains disabled The modules has no parameters 3 4 4 9 Spot removal Overview Spot removal allows you to correct an area in your 2008 spot removal v image by using another area as model gl eat em right click to remove a stroke ee of strokes 0 Usage 96 This module uses some of the shapes that are offered in drawn masks namely circles ellipses and path shapes The user interface and the controls are the same as in drawn mask and explained in more detail in Section 3 2 7 Drawn mask Select the desired shape by clicking the corresponding icon then click on the canvas to choose the area to be healed i e the target area The source areais preliminary positioned at a location with a default distance to the target Source area and target area can then
50. ing For zoomed out darkroom mode see Section 7 2 Core options is set accordingly Else color channels are taken from neighboring pixels without an expensive interpolation method Set the demosaic method darktable currently supports PPG AMAZE and VNG4 for Bayer sensors For X Trans sensors darktable supports VNG Markesteijn 1 pass and Markesteijn 3 pass edge threshold Set the threshold for an additional median pass Defaults to 0 which disables median Filtering This option is not shown For X Trans sensors color smoothing Activates a number of additional color smoothing passes Defaults to off match greens In some cameras the green filters have slightly varying properties This parameter adds an additional equalization step to suppress artifacts Available options are disabled local average Full average and Full and local average This option is not shown for X Trans sensors 3 4 1 8 Highlight reconstruction Overview Usage 12 This module tries to reconstruct color information 0 highlight reconstruction that is usually clipped because of incomplete infor method clip highlights 7 mation in some of the channels IF you do nothing your clipped areas are often toned to the not clipped channel For example if your green and blue chan nels are clipped then your image will appear red in the clipped areas clipping threshold n 1 000 You can choose between
51. is attached to the image red yellow green blue purple the title as listed in the image s metadata title Field the description as listed in the image s metadata description Field the creator as listed in the image s metadata creator Field the publisher as listed in the image s metadata publisher Field the copyrights statement as written in the image s metadata rights Field the EXIF data entry describing the lens the ISO value as derived from EXIF data the aperture value as derived from EXIF data the Filename of the physical input image In the text Field to the right of the attribute you write a pattern The pattern is compared against all database entries with the selected attribute This search detects a match if the images attribute contains the pattern in its Full text You may use as wildcard character The collection gets limited to those images where the query matches Leaving the text Field empty matches all images for that attribute The box below the search rule will list all matching database entries of the query you are currently working on This list gets updated continuously as you type You may also choose sorting criteria by scrolling through the list and double clicking Clicking on the triangle button to the right of the text Field opens a drop down menu with options to finetune your current collection by adding Further rules or removin
52. it here because darktable database has non numeric indices which are Functions to manipulate the database itself adding or deleting images for example e iterating through a table will return both the key and the value used It is conventional in lua to use a variable named _ to store values that we don t care about e Note tha we use the standard lua Function tostring here and not the darktable spe cific darktable debug dump The standard Function will return a name For the object whereas the debug Function will print the content The debug Function would be too verbose here Once again it is a great debug tool but should not be used for anything else 8 1 4 Adding a simple shortcut So far all our scripts have done things during startup This is of limited use and doesn t allow us to react to real user actions To do more advanced things we need to register 154 a Function that will be called on a given event The most common event to react to is a keyboard shortcut darktable require darktable TeoGaelk function heLlo snort eure venu shor ceu darktable print Hello I just received event T Wie paraneter SO sS NOrCCUC m N end darktable register_event shortcut hello_shortcut A shortcut that print its parameters Now start darktable goto preferences gt shortcut gt lua gt A shortcut that print its parameters assign a shortcut and try it You should have a nice message printed on the scree
53. module b Select the blue channel and set the blue color value to 0 8 c Select the red channel and change the blue color value to 0 1 d Select the green channel and change the blue color value to 0 1 4 Splittoning We use splittoning Section 3 4 5 3 Splittoning to add some more coloring to the re sult For cyan blue shadows and yellow highlight a Enable the splittoning module b Select a cyan blue tone for shadows and set saturation around 50 c Select a yellow orange tone for highlights and set saturation around 70 d Set compression to 10 e Use the balance slider to tune the splittoning effect This differs on every image due to it s exposure motive etc 3 5 3 Cyan toned image 3 5 3 1 Overview Cyan is a nice color touchup for black and white im ages this example guides you through how to make this with darktable and how to control the tone You can choose any tone of your like For this tutorial 3 5 3 2 Procedure This procedure uses monochrome channel mixer and splittoning modules 1 Image preparation Prepare the image for the cyan toned steps by adjusting the base settings such as exposure black level contrast etc For a correctly looking image 2 Black and white Enable the monochrome module Section 3 4 3 6 Monochrome to make the image black and white 3 Add color tone This step selects the base tone of the image using channel mixer Section 3 4 3 2 Chan nel mixer
54. note that all images are here This table is not influenced by any GUI Filtering collec tions stars etc darktable database types dt_lua_image_t Each image in the database appears with a numerical index you can interate them using ipairs darktable database duplicate LUnCE ron image types dt_lua_image_t types dt_lua_image_t Creates a duplicate of an image and returns it image types dt_lua_image_t the image to duplicate return types dt_lua_image_t The created image if an image is imported or the toplevel film object if a Film was imported darktable database import PUnCE LOT Location ise iG Imports new images into the database location SErING The Filename or directory to import images from NOTE IF the images are set to be imported recursively in preferences only the toplevel Film is returned the one whose path was given as a parameter NOTE2 If the parameter is a directory the call is non blocking the film object will not have the newly imported images yet Use a post import film filtering on that film to react when images are actually imported 185 darktable database move_image Puneet ont image types dt_lua_image_t fidm Cypeswdt luaifilm Physically moves an image and all its duplicates to another film This will move the image File the related XMP and all XMP for the duplicates to the direc tory of the new film Note that the parameter order is not relevant ima
55. number together with the device name is displayed when you start darktable with darktable d opencl You can specify a device either by number or by name upper lower case and whitespace do not matter IF you have more than one device all with the same name you need to use the device numbers in order to differentiate them ayn A device specifier can be preceded by an exclamation mark in which case the device is excluded from processing this pixelpipe You can also give an asterisk as a wildcard representing all devices not mentioned explicitly before in that group Sequence order within a group matters darktable will read the list from left to right and whenever it tries to allocate an OpenCL device to a pixelpipe it will scan the devices in that order taking the first free device it finds darktable s default setting for opencl_device_priority is Oy KARAK Any detected OpenCL device is allowed to process our center view image The first Open CL device 0 is not allowed to process the preview pixelpipe As a consequence if there is only one GPU owned by your system preview pixelpipe will always be processed on CPU keeping your single GPU exclusively For the more demanding center image view This is reasonable and identical to the old behavior No restrictions apply to export and thumb nail pixelpipes The default is a good choice if you have only one device IF you have several devices it Forms
56. of an image You can at your choice draw a mask using various shapes or define a para metric mask based on pixel values Most modules can exist as multiple instances Together with the mask Feature you can let an operation have different effects on different parts of the image darktable introduces a highly efficient yet simple single click denoiser that always just works It s designed as a module where the denoising performance only depends on camera and ISO setting A database of profiles contains parameters for over 100 popular camera models darktable comes with a versatile scripting interface For Functionality enhancement us ing Lua as a scripting language 1 1 Program invocation darktable comes with two binaries the standard GUI variant which is started by call ing darktable and a command line interface variant which is started by calling dark tebe cla i 1 1 1 darktable binary This binary starts darktable with its GUI and Full Functionality it is the standard way of using darktable darktable is called with the following command line parameters darktable d all cache camctl control dev fswatch input lighttable masks memory nan opencl perf pwstorage sql IMG_1234 RAW image_folder version Pe opencl Library lt Library file gt datadir xdata directory moduledir lt module directory tmpdir lt tinp directory gt sgoni igdir lt ser contig directory
57. of dark colors with individual sliders for each RGB color and with a Fac tor slider acting on all three colors at once gamma gain Adjusts the mid tones with individual sliders For each RGB color and with a Factor slider acting on all three colors at once Adjusts the high tones with individual sliders For each RGB color and with a Factor slider acting on all three colors at once 87 3 4 3 9 Vibrance Overview Usage Vibrance is a widely used term in image processing 2080 vibrance Y but the mechanism and end result differ from pro vibrance 25 gram to program Vibrance in darktable saturates vas ad and brings down the lightness of the most saturated pixels to make the colors more vivid Vibrance only has one parameter which controls the amount applied vibrance The amount of vibrance to apply to the image 3 4 3 10 Input color profile Overview Usage profile This module can be used to override darktable s au 0 input color profile Y tomatic allocation of input color profile if there is an profile enhanced color matrix 7 alternative that more closely matches your original image s color space gamut clipping off Y In this module you define the input color profile i e how colors of your input image are to be interpreted You also have an option to have colors confined to a certain gamut in order to mitigate some infrequent color artifacts Choose the profile or color matr
58. override all automatically selected parameters Either take one of the predefined values from the pull down menu or with the pull down menu still open just type in your own value IF you system s lensfun library has no correction profile for the automatically identified camera lens combination the controls for the three photometric parameters are not dis played and you get a warning message instead You may try to Find the right profile your self by searching for it in the menu IF there is no matching profile For your lens please visit this lens calibration service http www darktable org 2013 07 have your lens cali brated offered by Torsten Bronger one of darktable s users Alternatively you may go to lensFun s home page http lensFfun berlios de and learn how to generate your own set of correction parameters Don t Forget to share your profile with the lensfun team corrections This combobox gives you a choice about which corrections out of distortion TCA and vignetting darktable shall apply Change this From its default all if your camera has already done some internal corrections e g of vignetting or if you plan to do certain corrections with a separate program geometry In addition to the correction of lens flaws this module can change the projection type of your image Set this combobox to the aimed projection type like rectilinear Fish eye n u panoramic equirectangular
59. shape rather than something like path 32 Clicking on the shape name shows the selected shape in the center canvas with all its controls This is a convenient way to edit the properties of a specific shape Especially if there are so many shapes within a mask that their controls overlap and make it difficult to hit the right target Right clicking on a shape name gives you a drop down menu with the options to remove the current shape or to remove all shapes currently not in use All shapes ever defined for the current image are kept in the list unless you remove them explicitly IF you have worked a lot with shapes on one image this list can get quite long All settings with all defined shapes are part of the XMP tags of an image and are included in exported Files IF the list of shapes is very long the needed space to store all shapes might exceed the given limits of certain File Formats like JPEG In that case storing the XMP tags might Fail during export This is normally not a problem however you can no longer 59 rely on the exported file to contain your full history stack see Section 2 3 12 Export selected 3 3 5 4 Masks Clicking on the name of a mask expands a list showing the individual shapes which consti tute that mask Right clicking on the shape name opens a drop down menu Here you define the way that the individual shapes interact to form the mask You can also re move shapes from that mas
60. supports SVG files with embedded images that can be used as a texture source Blending operators then allow control of how that texture is expressed Gritty details When blending operators were introduced into dark table a new module named highpass see Sec tion 3 4 5 7 Highpass was added It provides a highpass Filter of the image to be implicitly used with blending Itis used to produce a gritty detailed image and is a method widely used in the workflow of other imaging software highpass This is the original image pretty heavily processed First monochrome then some blue splittoning but as you see it lacks pop in details and is a bit out of Fo CUS Here we applied the highpass filter with the values shown above You can now see that the details are greatly boosted and we now have a really gritty de tailed image 3 2 6 Blending operators There are several blend modes implemented and more might be added in Future For now all of the most commonly used ones are included and you will recognize a few of them From other imaging software A good introduction on many common blend modes is giv 45 en in The Gimp Manual Chapter 8 2 Layer Modes http docs gimp org 2 8 en gimp concepts layer modes html Therefore we only discuss a few blend modes here in more detail 3 2 6 1 blend modes normal This will probably be the most used blend mode It just mixes input and output and de p
61. the effect s strength You can also use blending operator normal to tame the effect see Section 3 2 6 Blending operators As the color map ping module comes early in the pixelpipe you can Finetune the colors with modules like tone curve see Section 3 4 2 3 Tone curve or color correction see Section 3 4 3 5 Col or correction acquire as source target Press these buttons to generate color clusters for the source and target image respec tively The processing takes a few seconds during which the GUI remains unresponsive number of clusters Sets the number of color clusters to use IF you change this parameter all collected color clusters are reset and need to be acquired anew color dominance This parameter controls the mapping between source and target clusters At the lowest value mapping is based on color proximity This typically leads to very subtle effects on the target image At the maximum value mapping is based on the relative weight of the 113 color clusters dominant colors of the source image are mapped to dominant colors of the target image This typically leads to a very bold effect In between values incrementally shift between the extremes histogram equalization Besides mapping of color characteristics this module can modify the target image s con trast by matching its histogram with the histogram of the source image This slider con trols the extent of the effect Examples
62. to darktable as an ICC profile To investigate your display profile configuration you can call the darktable cmstest binary which prints out useful information like profile name per monitor and tells you if the system is correctly configured 3 2 10 1 darktable s color spaces darktable s input images are either RGB files like JPEGs or TIFFs or pre demosaiced cam era raws both represent colors by a combination of red green and blue Most part of our modules act in the CIELAB color space http en wikipedia org wiki Lab_color space often just called Lab which describes color as a combination of lightness data L and a point in the a b color plane The final output of the image processing pipeline is once again in RGB either shaped For the monitor display or the output file This process implies that the pixelpipe has two color conversion steps input color profile and output color profile In addition there is the demosaic step for raw images where the colors of each pixel are reconstructed by interpolation Each module has a Fixed position in the pixelpipe which tells you which color space the module lives in up to demosaic Image is in raw data format with only latent colors Each pixel carries lightness and color information for only one base color Please mind that some of the modules in this part can also act on non RAW input images in RGB format with full information on all three color channels between demosaic
63. to lighten the im age In this example an RGB mix of 0 4 0 75 0 15 uses more green than red bringing back some Features We still reduce the blue channel in the mix to de em phasize unwanted skin texture Table of mixing values for some b w films Classic black and white films have different characteristic color responses Select gray as output mixing channel and try out the values suggested below For your Favorite film type Film Type Red Green Blue AGFA 200X 0 18 0 41 0 41 Agfapan 25 0 25 0 39 0 36 Agfapan 100 0 21 0 40 0 39 Agfapan 400 0 20 0 41 0 39 Ilford Delta 100 0 21 0 42 0 37 Ilford Delta 400 0 22 0 42 0 36 Ilford Delta 3200 0 31 0 36 0 33 Ilford FP4 0 28 0 41 0 31 Ilford HP5 0 23 0 37 0 40 Ilford Pan F 0 33 0 36 0 31 Ilford SFX 0 36 0 31 0 33 Ilford XP2 Super 0 21 0 42 0 37 Kodak T Max 100 0 24 0 37 0 39 Kodak T Max 400 0 27 0 36 0 37 Kodak Tri X 400 0 25 0 35 0 40 Normal Contrast 0 43 0 33 0 30 High Contrast 0 40 0 34 0 60 Generic B W 0 24 0 68 0 08 3 4 3 3 Output color profile 82 Overview Usage This module manages the output profiles for display output color profile and export as well as the rendering intent to be used output intent perceptual 7 when mapping between the different color spaces scape ces TS softproof profile sRGB web safe Y darktable comes with pre defined profiles sRGB display profie system display profile AdobeRGB XYZ and linear RGB but you can provide additional pr
64. to the desired highlight tint and then select a tint for shadows with the dark spot For a simple global tint set both spots to the same color saturation Use the saturation slider to correct the global saturation 3 4 3 6 Monochrome Overview This module is a quick way to convert an image into y OD monochrome Y black and white and provides a variable color filter For that conversion highlights blend Usage The default central location of the Filter has a neutral effect but dragging it to an alternate position applies a Filter analogously to taking a b amp w photograph through a conventional color Filter As well as position you can change the filter size by scrolling with your mouse wheel This makes the filter s range of hues more or less selective 85 Tip First reduce the Filter size to concentrate its effect and move it across the hue pallet to Find the best filter value for your desired image rendition Then expand the filter to include more hues and thus more natural tonality Under certain conditions especially highly saturated blue light sources in the frame this module may produce black pixel artifacts See the gamut clipping option Section 3 4 3 10 Input color profile on how to mitigate this issue 3 4 3 7 Color zones Overview This module selectively modifies the colors in your image It is highly versatile and allows every transfor mation possible in the LCh colorspace lightness Satura
65. translate these numerical values into Lab color space Beware that Lab values are approximated here depending on monitor color profile there can be some deviations From the real values When the checkbox restrict histogram to selection is ticked only the values of your se lected area or point are taken into account by the main histogram at the top of the right hand panel see Section 3 3 6 Histogram This is a way to show which tonal values are present in a specific area The sampled colors in either area or point mode can be stored as live samples by pressing the add button darktable will then show a color swatch and numerical values for each stored sample You can once again select which numerical value mean min max is to be displayed and if this is to be done in RGB or Lab color space Newly created live samples are not locked IF you change your image the changes will be reflected in your live samples Use this if you want see how changing parameters effects different parts of an image Clicking on a live sample s color swatch locks it and a lock symbol is displayed Further image changes will then no longer affect the sample You can For example take two live samples from the same location and lock just one of them to provide a before and after sample comparison Live sample locations are indicated in your image if you check option display sample areas on image 3 3 5 Mask manager 3 3 5 1 Overview
66. we are going For cyan tone but you can choose any tone that you like here a Enable the channel mixer module b Select the red channel destination and set the red color value to 0 7 c Select the green channel destination and set the green color value to 1 15 d Select the blue channel destination and set the blue color value to 1 15 As you notice we mix blue and green color to get a cyan tone we substract 0 3 From the red channel and add them to blue and green 4 Splittoning The result of the previous step does also add a color cast on highlights that we actually want to have white for a prettier result We also want to add some blue color cast to the shadows in order to emphasis them Module splittoning Section 3 4 5 3 Splittoning can accomplish this a Enable the splittoning module b Select a blue cyan tone for shadows and set saturation around 50 c Set highlights saturation to zero to remove saturation on highlights d Set compression to zero 119 e Use the balance slider to tune the effect our example uses a balance of 70 30 3 5 4 Removal of red eye effect 3 5 4 1 Overview The red eye effect in photography is the common ap pearance of red pupils in color photographs of eyes It occurs when using a photographic Flash very close to the camera lens as with most cameras with build in Flash in ambient low light We use the channel mixer module to reduce the red color of the pupil To limit the processing
67. will most likely be sup ported by darktable Even if successful if you stumble upon a problem in darktable please File a bug at redmine http www darktable org redmine Please attach the log outputs From the steps above and the log File output generated after starting darktable with the Following command darktabtle d gameti 22L Scamcul wLog 127 128 Chapter 5 Map The Map view is were you geotag your images 129 5 1 Overview Map view will show you a world map with the currently open image or Film roll of images pinned to their geotagged location This requires that the image was geotagged by a cam era with that Feature Some newer cameras including smartphones are already equipped with GPS receivers Other cameras may need additional GPS hardware to do this Even if your camera doesn t support this feature there is an alternative method darktable can match the EXIF time and date data in your image s to a separate GPX data tracking File created by a GPS tracker recording your movements These can be handheld devices or a GPS tracker app on your smartphone This is all done in the lighttable view see Sec tion 2 3 9 Geotagging 5 1 1 Center map view 130 In the center of the map view you will see a map Map data are taken from open map sources on the internet New map data are only avail able if you are connected to the internet darktable keeps a disk cache of previously loaded map data Yo
68. BLE VERSION IMAGE ID IMAGE FILENAME IMAGE EXIF EXIF DATE EXIF DATE SECOND EXIF DATE MINUTE EXIF DATE HOUR EXIF DATE HOUR_AMPM EXIF DATE DAY EXIF DATE MONTH EXIF DATE SHORT_MONTH EXIF DATE LONG_MONTH EXIF DATE SHORT_YEAR EXIF DATE LONG_YEAR S DATE SECOND DATE MINUTE DATE HOUR DATE HOUR_AMPM The application name The version of darktable The unique image id within current library The image Filename The image exif string The image date Seconds from the image EXIF data Minutes from the image EXIF data Hours from the image EXIF data 24h Hours From the image EXIF data 12h AM PM Day From the image EXIF data Abbreviated year from the image EXIF data 2013 is 13 Full year from the image EXIF data Current system date Current system time seconds Current system time minutes Current system time hours 24h Current system time hours 12 AP PM 101 S DATE DAY Current system time day S DATE MONTH Current system time month S DATE SHORT_MONTH DATE LLONG_ MONTH S DATE SHORT_YEAR Current system time year abbreviated S DATE LONG_ YEAR Current system time year S EXIF MAKER The maker of camera model S EXIF MODEL The camera model S EXIF LENS The specific lens used S Xmp dc creator The creator string S Xmp dc publisher The publisher string S Xmp dc title The title of the image S Xmp dc description The description of the image S Xmp dc ri
69. Full size export default at most ppg reasonable pixel interpolator Pixel interpolator used in rotation lens correction up and downscaling options are bi linear bicubic lanczos2 lanczos3 default password storage backend to use The storage backend for password storage Options none kwallet gnome keyring default none look for updated xmp files on startup Check file modification times of all XMP files on startup to find out if any got updated in the meantime by some other software IF updated XMP files are Found a menu opens For the user to decide which of the XMP files to be reloaded replacing darktable s data base entries by the XMP file contents and which of the XMP files to be overwritten by darktable s database default off executable for playing audio files Defines an external program which is used in the lighttable view to play audio files that some cameras record to keep notes for images default aplay 142 7 3 Session options These options define a naming pattern to organize images on disk when importing from a connected camera see Section 2 3 1 Import and when taking photos in the tethering view see Chapter 4 Tethering The naming pattern consists of three parts a base part defining the parent Folder a ses sion part defining a sub directory which is specific to the individual import session and a File name part defini
70. Low light Overview The low light module allows one to simulate human lowlight vision thus providing ability to make low light pictures look closer to reality It can also be used to perform a day to night conversion The idea is to calculate a scotopic vision http en wikipedia org wiki Scotopic_vision image which is perceived by rods rather than than cones in the eye under low light Scotopic lightness then is mixed with photopic value regular color image pixel using some blending Function Also this module is able to simu late the Purkinje effect http en wikipedia org wi ki Purkinje_effect by adding some blueness to the dark parts of the image and final image after this was applied with blend mode vividlight lowlight vision blue shift blend Usage This module comes with several presets Give them a try to get a better feeling how it works curve The horizontal axis is about pixel lightness from dark left to bright right The vertical axis represents the kind of vision from night vision bottom to day vision top blue Set the blue hint in shadows Purkinje effect Examples 110 Image 1 This is the original image Image 1 With low light module on Image 2 This is the original image Image 2 With low light module on 3 4 5 10 Bloom Overview This module boost highlights and creates a soft blooms them over the image hence the name of the threshold effect There
71. Modifying the output channel gray a Set output channel destination to gray b Set red color value to 0 24 c Set green color value to 0 68 d Set blue color value to 0 08 You are free to experiment what gives you the most realistic pupil but this is a good starting point The sum of the three values should be 1 122 Chapter 4 Tethering The tethering view allows you to capture images directly into darktable from your con nected camera 123 4 1 Overview To use the tethering feature you need to connect your camera to your PC using a USB cable Your computer might ask to mount or view the connected camera Do not mount or view the camera If that happens automatically you will need to unmount eject the camera This is required to unlock the camera so darktable can lock it for usage After the USB cable is connected look at the import panel in lighttable mode see Sec tion 2 3 1 Import IF your camera is not visible in this panel click the scan devices button and it will appear with two Functions import from camera and tethered shoot Click tethered shoot to enter the tethering mode darktable uses gphoto2 to interface with your camera IF you have problems finding the connected camera as described above check the troubleshoot section in this chapter in order to verify your camera has tethering support 4 1 1 Tethering 124 In the center view images are s
72. OB CODE 143 File naming pattern The file name part of the naming pattern default S YEAR S MONTH S DAY _ SE QUENCE FILE_EXTENSION 144 7 4 Shortcuts darktable has a large set of keyboard shortcuts that with the work of Robert Bieber is now user configurable through the preference pane When you open the shortcuts menu you are presented with a hierarchical list of all actions that can receive a keyboard shortcut Go to the action you want to change and double click You are then prompted to press the new key combination to be mapped to the selected action In order to remove an existing keyboard shortcut click on the action and press backspace You can export your mappings to a file or import mappings from a file Press default to reset all keyaccelerators to their default state Below is a table with the default keybindings For actions available in darktable lt darktable gt global lighttable view lt darktable gt global darkroom view lt darktable gt global capture view lt darktable gt global map view lt darktable gt global increase brightness lt darktable gt global decrease brightness lt darktable gt global increase contrast lt darktable gt global decrease contrast lt darktable gt global leave Fullscreen lt darktable gt global quit lt darktable gt global switch view lt darktable gt global toggle Fullscreen lt darktable gt global toggle header lt darktable gt glo
73. RW1 RW2 SR2 SRF SRW STI TIF TIFF X3F IF darktable was compiled with JPEG2000 support these extensions are also recognized J2C J2K JP2 JPC 23 IF darktable was compiled with GraphicsMagick support the Following extensions are rec ognized in addition to the standard ones BMP DCM GIF JNG JPC JP2 MIFF MNG PBM PGM PNM PPM Camera RAW files darktable reads RAW files using two open source libraries RawSpeed developed by Klaus Post and Failing that with LibRaw The number of supported cameras and File Formats is constantly increasing It is beyond the scope of this manual to give an exhaustive list Most modern camera models are supported and new ones tend to get added very quickly With the exception of Fujifilm X Trans cameras darktable does not decode images from cameras with non Bayer sensors e g Sigmas with the Foveon X3 sensor LDR image files darktable natively reads ordinary images in JPEG 8 bit 16 bit PNG and 8 bit 16 bit TIFF Format JPEG2000 is also supported if the required libraries are built into darktable at compile time Similarly if darktable was compiled with GraphicsMagick support there are Further import Formats like GIF Dicom DCM additional exotic TIFF formats and some of Sun s portable xyz map Family HDR image files darktable reads high dynamic range images in OpenEXR RGBE and PFM format 2 3 2 Collect images The current view in lighttable is called a
74. See Section 2 3 11 Tagging for more details Places Virginia Warrenton Bethany Lane cascais tagging Y Chapter 6 Slideshow The slideshow view starts a slideshow of your current collection 133 6 1 Overview 134 Entering the slideshow view starts a slideshow of the images of the current collection with Filtering rules and sort order applied To learn more on how to define the collection the Filtering and the sort order see Section 2 3 2 Collect images and Section 2 2 5 Filtering and sort order The image display is optimized to take Full advantage of your screen size You should there Fore put darktable into Fullscreen mode which is toggled by pressing F11 You may press TAB in order to hide all remaining panels namely the filtering option in the top panel 6 2 Usage The slideshow view is in an early stage of development with a basic set of Features left click switch to the next image of the collection right click switch to the previous image of the collection space start and stop auto advance mode which automatically switches to the next images every Five seconds and after the last image loops back to the beginning ESC leave slideshow mode and return to lighttable view Depending on the complexity of the history stack and the power of your hardware pro cessing an image with high resolution can take a significant amount of time darktable prefetches the next image in the backgro
75. User interface This section describes the layout of the user inter Face 1 2 1 Views darktable consists of several views or modes There are five available views as described in this section You can switch between views by clicking the view name at the top of the right panel the active view is highlighted or by using one of the key accelerators l switches to lighttable d switches to darkroom t switches to camera tethering m switches to map S switches to slideshow 1 2 1 1 Lighttable The lighttable view is where images and film rolls are managed It s also where you rate images add tags and colorlabels and export images among other actions see Chapter 2 Lighttable 1 2 1 2 Darkroom In the darkroom view you develop a single image using the available modules see Chap ter 3 Darkroom 1 2 1 3 Tethering This view is for shooting with the camera connected to the computer and remotely cap turing images that will be downloaded and shown on computer screen see Chapter 4 Tethering 1 2 1 4 Map This view shows images with geo tag data on a map and allows manually geo tagging new images see Chapter 5 Map 1 2 1 5 Slideshow This view shows images as a slideshow processing them on the fly see Chapter 6 Slideshow 1 2 2 Screen layout The general screen layout of all views is similar There is a center area which contains most of the relevant information of that view Then there are panels le
76. _lua_tag_t The tag to be detached image types dt_lua_image_t The image to detach the tag from darktable tags get_tags EUNnCE LON image types dt_lua_image_t table of types dt_lua_tag_t Gets all tags attached to an image image types dt_lua_image_t The image to get the tags from return table of types dt_lua_tag_t A table of tags that are attached to the image 8 2 1 10 darktable configuration table This table regroups values that describe details of the configuration of darktable 177 darktable configuration version string The version number of darktable darktable configuration has_gui boolean True if darktable has a GUI launched through the main darktable command not dark table cli darktable configuration verbose boolean True if the Lua logdomain is enabled darktable configuration tmp_dir string The name of the directory where darktable will store temporary Files darktable configuration config_dir string The name of the directory where darktable will Find its global configuration objects mod ules darktable configuration cache_dir string The name of the directory where darktable will store its mipmaps darktable configuration api_version_major number The major version number of the lua API darktable configuration api_version_minor number The minor version number of the lua API darktable configuration api_version_patch number The patch version number of the lua API darktable conf
77. _module_storage_data_gallery title string The title to use for export Attributes e write 8 2 2 19 types dt_imageio_module_storage_data_disk dt_type 201 An object containing parameters to export to disk Attributes e parent types dt_imageio_ module storage t types dt_imageio_module_storage_data_disk filename string The filename to export to Attributes e write 8 2 2 20 types dt_lua_Film_t dt_type A Film in darktable this represents a directory containing imported images Attributes e has_tostring types dt_lua_film_t move_image see darktable database move_image types dt_lua_film_t copy_image see darktable database copy_image types dt_lua_film_t types dt_lua_image_t The different images within the Film types dt_lua_film_t id number A unique numeric id used by this Film Attributes e write types dt_lua_film_t path SCEL The path represented by this film Attributes e write types dt_lua_film_t delete SeLitrunce lon force s Boolean Removes the film From the database 202 self types dt_lua_film_t The Film to remove Force Boolean Force removal even if the film is not empty 8 2 2 21 types dt_style_t dt_type A style that can be applied to an image Attributes e has_tostring types dt_style_t delete see darktable styles delete types dt_style_t duplicate see darktable styles duplicate types dt_style_t apply see darktable styles apply types dt_style_t export see darktab
78. ach of its data channels real and virtual All blending Factors are Finally pixel wise multiplied together with the value of the global opacity slider see Section 3 2 6 Blending operators to forma blend mask For the image IF For a given pixel the blend mask has a value of 0 the input of the module is left un changed If for a pixel the blend mask has its maximum value of 1 or 100 the module has Full effect 3 2 8 2 Usage When parametric mask IS activated in combobox blend parametric mask 7 blend an additional set of tabbed controls is shown mala sells opacity 100 ji a J oao output 4 input y combine masks mash blur Channel tabs Each tab selects a data channel real or virtual Modules acting in Lab color space have data channels for L a b C chroma of LCh and h hue of LCh Modules acting in RGB color space have data channels for g gray R G B H hue of HSL S saturation of HSL and L lightness of HSL Consult for example Wikipedia s article on color spaces http en wikipedia org wiki Color_space for a deeper look Each tab provides two sliders For its data channels one for the input data that the module receives and one for the output data that the module produces prior to blending Color channel sliders With the color channel slider you construct a trapezoidal opacity Function For this purpose there are four markers per slider Two triangles above the slider mar
79. age in the darkroom view To begin open an image in darkroom mode by double clicking an image thumbnail on the lighttable The darkroom mode is where the actual adjustments for an image are made where an arsenal of modules are at hand to help you reach your goal Each change made on a module while developing an image is turned into a history stack item The history is stored in a database and in an XMP sidecar File For the specific image All changes are stored automatically You can safely leave darkroom mode or quit dark table at any time and come back later to continue your work That said darktable does not need a save button and it does not have one On the left panel in darkroom mode is the history stack showing changes starting from bottom and building up with each change made to the image You can select a point in this history to show how the image looked at that point for comparison of changes The stack can be compressed it will be optimized and redundant changes will be discarded When you think you are done and are happy with what you have done just compress the history stack darktable ships with a number of modules arranged into groups These module groups are accessed via toggle buttons in the right panel just under the histogram There are also two special module groups named active and Favorites which only show modules enabled in the history for the current image and modules selected as a Favorite r
80. ain a time zone Most people set their camera to local time while the GPS devices store the time in UTC Uni versal Time Coordinated i e Greenwich London time zone If the time zones of camera and GPX file differs than the related location will be wrong If your image already carry the UTC time stamp you can directly apply the GPX track with out further adjustments Otherwise we take two steps to correlate the time of camera and GPS tracker first the offset then the time zone To fix the drift of the camera time setting you can ei ther enter it manually into the offset input field or let darktable calculate it All you need is a picture taken of areliable time source This can be any precise clock or even better the time displayed on your GPS device normally it shows the local time although it stores universal time When you have this image selected you can click on the looking glass button and darktable will present you an entry box Just enter the time that is shown 4 on the image As a result you will get the difference E GARMIN between the time you entered and the one associat ed with the image in its EXIF data 18 16 49 x Cancel Now you can select all the images you want to geotag and click the apply button currently represented by a check mark This will alter the time in darktable s internal database for these pictures so you will also see the change in the image information module on the left Now y
81. al split view 3 3 3 History stack The history stack lists every change of state acti vate de activated for all modules Here you can se lect a point in stack to return to that point of devel opment history IF you then activate a new module or change a module parameter all modules above the current point will be discarded Caution activating any module action using key accelerators will discard all modules above the currently selected one It is easy to lose all development work on an image this way Hitting compress history stack generates the shortest history stack that produces the current image i e suppressing all de activated modules This also will discard all modules above the currently selected one The button to the right Hf lets you create a new style for applying your history stack to other images Use the first line of the popup dialog window to name your style and the second to add a searchable description You are prompted for which of the current history stack modules to include in the style Once created styles are then managed and applied to other images in the lighttable s styles panel see Section 2 3 8 Styles 57 3 3 4 Global color picker 58 Using the global color picker you can take color sam Y color picker ples from your image display their values in multiple ways and compare colors from different locations The color picker is activated by pressing the amp icon z There are
82. alue controls the cache size in megabytes It needs a restart if changed default 512MB number of background threads This controls how many parallel threads are used to create thumbnails during import On 32bit systems it is strongly recommended to set this to 1 Needs a restart if changed de Fault 2 host memory limit in MB for tiling In order to manage large images on systems with limited memory darktable does tile wise processing This variable controls the maximum amount of memory in MB a module may use during image processing Lower values will force memory hungry modules to process an image with increasing number of tiles Setting this to 0 will omit any limits Values below 500 will be treated as 500 On a 32bit system you should set this to 500 Needs a restart if changed default 1500 minimum amount of memory in MB for a single buffer in tiling IF set to a positive non zero value this variable defines the minimum amount of memory in MB that darktable should take for a single tile On a 32bit system you should set this to 8 64bit systems can live with higher values Needs a restart if changed default 16 write sidecar File For each image These redundant XMP files can later be re imported into a different database preserving your changes to the image It s strongly recommended to have this option activated so you don t lose data in case of a database corruption Backing up your RAW file plus the accompanying XMP
83. alues intact 3 4 2 1 Fill light Overview This module allows local modification of the expo fill ight Y sure based on pixel lightness 0 33EV 14 Usage Pushes exposure by increasing lightness with a Gaussian curve of a specified width cen tered ona given lightness exposure Sets Fill light exposure in EV center Sets the median lightness impacted by the Fill light A color picker is activated by pressing E it shows the picked lightness value in the gradient bar which helps find the desired center value width Sets the width of the Gaussian curve This number is expressed in zones with the whole dynamic range being 10 zones As the Gaussian curve is symmetric only even numbers can be entered 3 4 2 2 Levels Overview A tool for adjusting black white and mid gray points 5 c levels v This module is especially useful if the histogram of node manual 7 an image does not span the whole horizontal range From pure black to pure white Usage The levels tool offers two modes of operation manual and automatic In manual mode the levels tool shows a histogram of the image and displays three bars with handles Dragging the handles modifies the tones in the image Those bars control the black middle gray and white points in absolute values of image lightness the L value from Lab You can move the black and white bars to match the left and right borders of the his togram which will
84. an darktable gui hovered or darktable gui selection to be consistant with darktable s GUI darktable gui hovered The image under the cursor or nil if no image is hovered 166 darktable gui selection function selection table of types dt_lua_image_t table of types dt_lua_image_t Allows to change the set of selected images Attributes implicit_yield selection table of types dt_lua_image_t A table of images which will define the selected images IF this parameter is not given the selection will be untouched IF an empty table is given the selection will be emp tied return table of types dt_lua_image_t A table containing the selection as it was before the Function was called darktable gui current_view FUINCE TO view types dt_view_t types dt_view_t Allows to change the current view view types dt_view_t The view to switch to IF empty the current view is unchanged return types dt_view_t the current view darktable gui create_job TUNGCETON Cex 2 isting percentage boolean cancel callback gt function e types dt Tua bDa kgroundJob rt Create a new progress_bar displayed in darktable gui libs backgroundjobs text string The text to display in the job entry 167 percentage boolean Should a progress bar be displayed cancel_callback F nction job types dt_lua_backgroundjob_t A Function called when the cancel button for that job is pressed note that the jo
85. and input Image is in RGB Format within the color space of the color profile specific camera or input file between input color profile Image is in Lab format This is a very huge universal and output color profile color space which covers all colors visible to the hu man eye and even more As darktable processes im ages in 4x32 bit Floating point buffers we can handle the Lab color space without risking banding or tonal breaks after output color profile Image is in RGB format as defined by the selected dis play or output ICC profile 3 2 10 2 Unbounded colors Theoretically the individual components of color data are confined to certain mininum and maximum levels As an example the intensity of an individual red green or blue color channel in RGB can be anything in the range between 0 and 100 or between 0 0 and 1 0 Likewise the L channel in Lab can be anything between 0 pure black and 100 pure white In practice sometimes the image processing steps in darktable s modules can lead to val ues which lie outside of these confined ranges In Fact even the well established color ma trices which convert from camera RGB to Lab may sometimes produce pixels with nega tive L values Pixels with these kind of values are said to have unbounded colors One could clamp i e confine those values to the allowed range at every processing step However it has been found that it is much preferred and less prone to artifacts to no
86. anel Recently used collections can be chosen with their respective names in a separate panel You can also get an overview of the information of the im age under your mouse cursor in a panel labeled im age information 5 2 2 Find location The find location module is used to search for a place find location on map You need to be connected to the internet to use this Feature To use type in a place or address press enter and a list of results will be shown Click on one of the re sulting items and the map will zoom to that location Now drag images from the film strip at the bottom of the screen to their location on the map The GPS location will be embedded in the image 5 2 3 Map settings In the map settings panel you can select your pre ferred map data from various providers Some will provide different layers such as satellite view etc which you can toggle map settings OpenStreetMap Maps For Free OpenCycleMap Public Transport Google Maps Google Satellite Google Hybrid Virtual Earth Virtual Earth Satellite Virtual Earth Hybrid 131 5 2 4 Tagging 132 The tagging panel allows you to attach or detach dif Ferent tags to an image as well as creating or delet ing a tag It is divided into two parts The upper part contains tags that are currently attached to the im age The lower part contains all available tags You must select or mouse over an image for the data to be displayed
87. are numerous ways to use this module ISS depending on the image s actual scenery lighting Ta Usage Starting from the default settings change the strength value for a pleasant look then change the size to control the spread of light size Represents the spatial extent of the bloom effect threshold Set the threshold for the increase in brightness strength Set the strength of overlightning For the effect 111 Examples This is the original image use it as reference for the changes below Here we have chosen to use a size of 10 which is a rather small radius for the soft light spread We boosted up the strength to 50 for a more exagger ated effect 3 4 5 11 Colorize Overview This module is an artistic Feature that adds a solid lay er of color to your image saturation lightness source mix blend Usage Several parameters control the effect of this module Much more versatility can be reached if you apply blending and masks see Section 3 2 5 Blending hue Selects the hue of the color layer saturation Selects the color saturation of shadow tones lightness Selects the lightness of the color layer source mix This slider controls how the lightness of the input image is mixed in IF you set this to zero a uniformly colored plane will result 3 4 5 12 Color mapping 112 Overview Usage This module transfers the look and Feel from one im 0 color mapping ag
88. arktable debug debug boolean Initialized to false set it to true to also dump information about metatables darktable debug max_depth number Initialized to 10 The maximum depth to recursively dump content 187 darktable debug known table A table containing the default value of darktable debug dump known darktable debug type function object anything string Similar to the system Function type but it will return the real type instead of userdata For darktable specific objects object anything The object whos type must be reported return string A string describing the type of the object 8 2 2 types This section documents types that are specific to darktable s Lua API 8 2 2 1 types dt_lua_image_t dt_type Image objects represent an image in the database This is slightly different from a File on disk since a file can have multiple developements Note that this is the real image object changing the value of a field will immediately change it in darktable and will be reflected on any copy of that image object you may have kept Attributes e has_tostring types dt_lua_image_t attach_tag see darktable tags attach types dt_lua_image_t detach_tag see darktable tags detach types dt_lua_image_t get_tags see darktable tags get_tags types dt_lua_image_t create_style see darktable styles create types dt_lua_image_t apply_style 188 see darktable styles apply types dt_lua_image_t duplicate see darktable data
89. ase curves to the RAW data when they generate in camera JPEG images with better colors and contrast darktable comes with base curve pre sets that mimic the curves of various manufacturers These are automatically applied to RAW images ac cording to the manufacturer ID found in EXIF data You can adjust an existing base curve or create a new one The base curve is defined by two or more nodes You can click on any node and drag to modify it You can also create additional nodes by clicking on a curve segment between two nodes In order to remove a node drag it outside of the widget area Tip IF you intend to take Full manual control of the tonal values with the tone curve module or the zone system module see Section 3 4 2 3 Tone curve and Section 3 4 2 4 Zone system it may be easier to leave the image in linear RGB Disable the base curve module in this case This combobox toggles between linear and logarithmic view In the double logarithmic view more space is given to the lower values allowing a more fine grained adjustment of the shadows 3 4 1 5 Exposure 69 Overview Usage mode black This module is used to tweak the exposure It is di 08 exposure rectly linked to the histogram panel Indeed iF you mode manual correct exposure graphically using the histogram aT _ see Section 3 3 6 Histogram you automatically ma l activate the exposure module The histogram simply blend
90. ather slow GPU In that case darktable might in fact save some time when module parameters have changed as it can go back to some cached intermediate state and reprocess only part of the pix elpipe In most cases this parameter should be set to FALSE default opencl_micro_nap In an ideal case you keep your GPU busy at 100 when reprocessing the pixelpipe That s good On the other hand your GPU is also needed to do regular GUI updates It 224 might happen that there is no sufficient time left For this task Consequence would by a jerky reaction of your GUI on panning zooming or when moving sliders darktable can add small naps into its pixelpipe processing to have the GPU catch some breath and do GUI related stuff Parameter opencl_micro_nap controls the duration of these naps in microseconds You need to experiment in order to find an optimum value for your system Values of 0 100 500 and 1000 are good starting points to try Defaults to 1000 opencl_use_pinned_memory During tiling huge amounts of memory need to be transferred between host and de vice Onsome devices namely AMD direct memory transfers to and from an arbitrary host memory region may give a huge performance penalty This is especially notice able when exporting large images Setting this configuration parameter to TRUE tells darktable to use a special kind of intermediate buffer for host device data transfers On some devices this can speed up exporting of large files b
91. avoid a cheap overprocessed look 3 4 2 6 Tonemapping Overview This module compresses the tonal range of HDR im ETI tone mapping ages so they fit into the limits of a normal low dy contrast compressign 2 500 spatial extent namic range image using Durand s 2002 algorithm blend 19 Usage darktable can import HDR images if they come in OpenEXR RGBE or PFM format or as a DNG generat ed by darktable s HDR creation mechanism see Sec tion 2 3 6 Selected image s The underlying algorithm uses a bilateral Filter to decompose an image into a coarse base layer and a detail layer The contrast of the base layer is compressed while the detail layer is preserved then both layers are re combined contrast compression Sets the contrast compression level of the base layer A higher compression will make the image Fit a lower dynamic range spatial extent Sets the spatial extent of the bilateral filter Lower values cause the contrast compression to have stronger effects on image details 3 4 2 7 Global tonemap Overview This modules implements another approach to com OF O08 global tonemap pressing the tonal range of an HDR image into the ses drago 7 limited tonal range of a typical LDR output file It of lt nr Fers several implementations of global tonemap op detail 0 000 erators blend off Y Usage 80 Global tonemapping processes each pixel of an HDR image without taking the local sur
92. b won t be destroyed automatically You need to set types dt_lua_backgroundjob_t valid to false for that job types dt_lua_backgroundjob_t The job who is being cancelded return types dt_lua_backgroundjob_t The newly created job object darktable gui views The different views in darktable darktable gui views map The map view Attributes e has_tostring e parent types dt_view_t darktable gui views map latitude number The latitude of the center of the map Attributes e write darktable gui views map longitude number The longitude of the center of the map Attributes e write darktable gui views map zoom number 168 The current zoom level of the map Attributes e write darktable gui views darkroom The darkroom view Attributes e has_tostring e parent types dt_view_t darktable gui views lighttable The lighttable view Attributes e has_tostring e parent types dt_view_t darktable gui views tethering The tethering view Attributes e has_tostring e parent types dt_view_t darktable gui views slideshow The slideshow view Attributes e has_tostring e parent types dt_view_t darktable gui libs This table allows to reference all lib objects lib are the graphical blocks within each view To quickly Figure out what lib is what you can use the Following code which will make a given lib blink local tested_module global_toolbox dt gui libs tested_module visible false coroutine yi
93. bal toggle side borders lt darktable gt views lighttable color red lt darktable gt views lighttable color yellow lt darktable gt views lighttable color green lt darktable gt views lighttable color blue lt darktable gt views lighttable color purple lt darktable gt views lighttable navigate down lt darktable gt views lighttable navigate page down lt darktable gt views lighttable navigate page up lt darktable gt views lighttable navigate up lt darktable gt views lighttable preview lt darktable gt views lighttable preview with focus detection lt darktable gt views lighttable rate 1 lt darktable gt views lighttable rate 2 lt darktable gt views lighttable rate 3 lt darktable gt views lighttable rate 4 lt darktable gt views lighttable rate 5 F7 Escape lt Primary gt q period F11 lt Primary gt h Tab F1 F2 F3 F4 F5 lt Shift gt g Page_Down Page_Up g Z lt Primary gt z 1 wm A W N 145 146 lt darktable gt views lighttable rate desert lt darktable gt views lighttable rate reject lt darktable gt views lighttable realign images to grid lt darktable gt views lighttable scroll center lt darktable gt views lighttable scroll down lt darktable gt views lighttable scroll left lt darktable gt views lighttable scroll right lt darktable gt views lighttable scroll up lt darktable gt views darkroom export lt darktable gt views darkroom image forward lt darktable gt views darkroom
94. base duplicate types dt_lua_image_t move see darktable database move_image types dt_lua_image_t copy see darktable database copy_image types dt_lua_image_Lt id number A unique id identifying the image in the database types dt_lua_image_t path string The file the directory containing the image types dt_lua_image_t film types dt_lua_film_t The film object that contains this image types dt_lua_image_t filename string The filename of the image types dt_lua_image_t duplicate_index number IF there are multiple images based ona same file each will have a unique number starting From 0 types dt_lua_image_t publisher string The publisher Field of the image Attributes e write types dt_lua_image_Lt title string The title Field of the image 189 Attributes e write types dt_lua_image_t creator SELLIG The creator field of the image Attributes e write types dt_lua_image_t rights string The rights field of the image Attributes e write types dt_lua_image_t description SErinG The description Field For the image Attributes e write types dt_lua_image_t exif_maker string The maker exif data Attributes e write types dt_lua_image_t exif_model String The camera model used Attributes e write types dt_lua_image_t exif_lens string The id string of the lens used Attributes e write types dt_lua_image_t exif_aperture 190 number The aperture saved in the exif data A
95. cally selects a unique new File name in case of naming conflicts The overwrite option gets reset after each export in order to protect you from accidental data loss File Format 34 darktable can export to various file Formats Depending on the output format you can define additional parameters For some formats you need to decide on the desired bit depth and the compression method respectively For some export formats like JPEG you can define an output quality Higher values will lead to larger file sizes The default quality 95 is a good setting for very high quality exports e g for archiving or printing purposes IF you need a good compromise between size and quality e g For online image display or uploads you should consider a value of 90 instead IF the File Format supports embedded metadata like JPEG JPEG2000 and TIFF darktable will try to store the history stack as XMP tags within the output file This information can later be used to reconstruct your parameters and settings that have produced the export ed image see Section 2 3 7 History stack max size intent profile style export Caution for various reasons embedding XMP tags into output files may fail without notice eg if certain size limits are exceeded Users are therefore advised to not rely their backup strategy on this feature To backup your data make sure to save your input RAW file as well as all of darktable s XMP sidecar fil
96. cation ui Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs backgroundjobs The window displaying the currently running jobs Attributes e has_tostring e parent types dt_ lib module _t 8 2 1 9 darktable tags Allows access to all existing tags darktable tags 175 types dt_lua_tag_t Each existing tag has a numeric entry in the tags table use ipairs to iterate over them darktable tags create f nctron name string Creates a new tag and return it IF the tag exists return the existing tag name Seri oG The name of the new tag darktable tags find PUNCE LOT name string types dt_lua_tag_t Returns the tag object or nil if the tag doesn t exist name SETTING The name of the tag to find return types dt_lua_tag_t The tag object or nil darktable tags delete EUnCCiGN tag Lyoes lt ct lua tag Deletes the tag object detaching it from all images tag types dt_lua_tag_t The tag to be deleted darktable tags attach FUnCELOnN tag types dt lua tag t image types dt_lua_image_t 176 Attach a tag to an image the order of the parameters can be reversed tag types dt_lua_tag_t The tag to be attached image types dt_lua_image_t The image to attach the tag to darktable tags detach Tune Lond tag types dt l a tag t image types dt_lua_image_t Detach a tag from an image the order of the parameters can be reversed tag types dt
97. ck Disabling this option reverts the meaning of click and shift click default off expand a single darkroom module at a time Controls how darkroom modules are expanded IF this option is enabled expanding a mod ule by clicking collapses any currently expanded module IF you want to expand a module without collapsing the others you do so with shift click Disabling this option reverts the meaning of click and shift click default on do high quality processing for slideshow Controls how images are processed for the slideshow view It this option is enabled the image will first be processed in Full resolution and downscaled at the very end This can result in better quality sometimes but will always be slower default on method to use for getting the display profile 140 This option allows to Force a specific way of getting the current display profile in the out put color profile module see Section 3 4 3 3 Output color profile In the default setting all darktable will either query the X display server s xatom or the colord system service You can set this option to xatom or colord to enforce a specific method if the alterna tive gives wrong results 7 2 Core options These options control some of the internals of darktable memory in megabytes to use for mipmap cache On order to speed up display of Film rolls darktable stores thumbnails in a cache on disk and loads it into memory at startup This v
98. cks in favor of smaller ones darktable 1 0 introduces a caching algorithm to address this problem It pre allocates blocks of memory and makes them available on request 9 1 4 Further limitations As if this were not challenging enough there are Further things that might limit your ac cess to memory On some older boards you need to activate BIOS option memory remap ping in order to have all physically installed memory enabled In addition if you are ona 32 bit OS you will probably need a kernel version that has Physical Address Extension PAE enabled This is often but not always the case for Linux Many distributions deliver different kernels some with and some without PAE activated you need to choose the right one To check if the system is setup correctly use the command free in a terminal and examine the output IF the output reports less RAM than you have installed you have an issue needing correction for example you have 4GB on your board but your kernel is only seeing 3GB or less You need to consult your BIOS manual and the information about your Linux variant For Further help 9 1 5 Setting up darktable on 32 bit systems As we ve seen 32 bit systems are difficult environments For darktable Still many users are successfully running darktable on them if the basic requirements in terms of total system memory and the topics mentioned in the paragraphs above are addressed properly There are several adjustment
99. collection Y collect images The collect images panel lets you narrow down the list fimrol ve pegelow Bilder Testbiider v of visible images to just the ones you want to work Testbilder darktable_exported wi th Bilder Testbilder Information about all images imported into darktable are kept in a database with various attributes describing each image You define a collection by applying certain Filtering rules to these attributes creating a subset of images to display in the lighttable view The default collection is based on the film roll attribute it displays all images of the last imported film roll or any other film roll chosen 2 3 2 1 Usage image attributes The left combobox lets you choose from the available attributes Film roll the Film roll to which the image belongs 24 Folders camera tag date time history color label title description creator publisher rights lens ISO aperture Filename search rules the disk Folder where the input image File is located the EXIF data entry describing the camera make and model any tag that is attached to the image if activated a hierarchical list of known tags is displayed for quick selection the date when the photo was taken in the Format YYYY MM DD the time date and time of day when the photo was taken in the Format YYYY MM DD hh mm ss choose images whose history stacks have been altered or not al tered a any color label that
100. ct blend mode and opacity value are displayed The default blend mode is normal with an opacity of 100 drawn mask reprocessing takes place with the chosen blend mode and opacity Additional controls are displayed which allow you to draw a mask IF no mask elements are drawn all pixels have the same opacity defined by the opacity slider IF you draw a mask element e g a circle the inner area of the circle will get maximum opacity surrounded by a transition area or border with a gradual decay of opacity and the remaining image with an opacity of 0 Different graphical shapes can be used See Section 3 2 7 Drawn mask for further details parametric mask reprocessing takes place with the chosen blend mode and opacity Additional controls are displayed which allow you to adjust the opacity on a per pixel basis determined by pixel values In previous versions of darktable this was called conditional blending See Section 3 2 8 Parametric mask for further details drawn and parametric mask this option combines drawn and parametric masks and shows the Full set of both controls See Section 3 2 9 Combining drawn and parametric masks to learn how to best use this combination Mask combination and inversion invert mask When drawn mask is selected there is an additional combobox to invert the mask by switching mask inversion on or off combine masks When either parametric masks o
101. ct the type of correction you want to use vertical if you want to limit the correction to vertical lines 65 horizontal limit the correction to horizontal lines free if you want to correct horizontal and vertical lines Depending on the selected correction type you will see two or four straight adjustment lines overlaid to your image Two red circles on every line let you mod ify the line positions with your mouse Each line ad ditionally carries a symmetry button If activated and highlighted in red all movements of the affect ed line will be mirrored by the opposite line In order to correct perspective distortions you need to Find suitable horizontal and or vertical Features in your image and align the adjustment lines with them When done press the OK button which is locat ed close to the center of your image The image will be corrected immediately You can at any time come back and refine your corrections by selecting correc tion applied in combobox keystone automatic cropping Use this options to avoid black edges on the image borders Useful when you rotate the image aspect Here you can change what aspect ratio you want to have on the result thus constraining the ability to drag and crop rectangle out of the aspect ratio of your choice Many com mon numerical ratios are pre defined You can also select any other ratio after opening the combobox and typing it in the Form of x y A Few sp
102. cuments events that can be used to trigger Lua callbacks 8 2 3 1 events intermediate export image event This event is called each time an image is exported once for each image after the image has been processed to an image format but before the storage has moved the image to its final destination events intermediate export image callback function event string image types dt_lua_image_t filename string format types dt_imageio_module_format_t storage types dt_imageio_module_storage_t event string 209 The name of the event that triggered the callback image types dt_lua_image_t The image object that has been exported Filename string The name of the file that is the result of the image being processed Format types dt_imageio_module_format_t The format used to export the image storage types dt_imageio_module_storage_t The storage used to export the image can be nil events intermediate export image extra registration parameters This event has no extra registration parameters 8 2 3 2 events post import image event This event is triggered whenever a new image is imported into the database This event can be registered multiple times all callbacks will be called events post import image callback FUnCELon event string image types dt_lua_image_t event String The name of the event that triggered the callback image types dt_lua_image_t The image object that has been exported
103. d that we can help you Please also report if you see significant differences between CPU and GPU processing of an image There also exists a Few on CPU implementations of OpenCL These come as drivers provid ed by INTEL or AMD We observed that they do not give us any speed gain versus our hand optimized CPU code Therefore we simply discard these devices by default This behavior can be changed by setting the configuration variable opencl_use_cpu_devices to TRUE 9 2 6 Setting up OpenCL for AMD ATI devices While NVIDIA devices and most modern AMD ATI devices will most often run out of the box there is more to do for older AMD ATI graphics cards namely those prior to the HD7xxx series This starts with the fact that those devices will only report to darktable 222 part of their total GPU memory For a 1GB device this typically amounts to 512MB a val ue which darktable in its standard configuration will refuse as not being sufficient For its tasks Consequence the device will not be used On the web you might find as a tip to set environment variable GPU_MAX_HEAP_ SIZE to a value of 100 in this case Indeed this will cause the AMD ATI driver to report the Full installed memory to darktable However there is a problem On many most cards this will cause buffers to be allocated on your computer host not on the video card In this case all memory accesses will need to go through the slow PCle bus This will cost you a Factor of 10x or
104. darktable 1 6 darktable 1 6 Copyright 2010 2012 P H Andersson Copyright 2010 2011 Olivier Tribout Copyright 2012 2014 Ulrich Pegelow Copyright 2013 2014 J r my Rosen The owner of the darktable project is Johannes Hanika Main developers are Johannes Hanika Henrik Andersson Tobias Ellinghaus Pascal de Bruijn and Ulrich Pegelow darktable has been developed with major contribution by Aldric Renaudin Alexandre Prokoudine Ammon Riley Andrew Toskin Andrey Kaminsky Antony Dovgal Artur de Sousa Rocha Brian Teague Bruce Guenter Cherrot Luo Christian Him pel Christian Tellefsen Dan Torop David Bremner Dennis Gnad Dimitrios Psychogios Eckhart Pedersen Edouard Gomez Fr d ric Grollier Gaspard Jankowiak Ger Siemerink Gianluigi Calcaterra Guilherme Brondani Torri Igor Kuzmin Ivan Tarozzi James C McPherson Jean S bastien P dron J r my Rosen Jesper Pedersen Jochen Schr der Johanes Schneider Jos Car los Casimiro Jose Carlos Garcia Sogo Josep Vicen Moragues Pastor Kaminsky Andrey Kanstantsin Shautsou Karl Mikaels son Loic Guibert Marcel Laubach Mauro Bartoccelli Michal Babej Michel Leblond Mikko Ruohola Milan Knizek Moritz Lipp Olivier Tribout Pascal Obry Pedro C rte Real Petr Styblo Richard Hughes Richard Levitte Richard Wonka Robert Bieber Roman Lebedev Rostyslav Pidgornyi Sergey Pavlov Simon Spannagel Stuart Henderson Tatica Leandro Thomas Pryds Vic tor Lamoine Wolfgang G
105. deliver quite varying effects For example the fill light module Section 3 4 2 1 Fill light allows local modification of lightness based on pixel values You might want to do two lightness corrections in your image at the same time one for dark tones and another one for lighter tones e You might want to apply a denoising module like denoise profile Section 3 4 4 3 De noise profiled with two different parameter sets One to do luma denoising and an other set of parameters to do chroma denoising You could do so by generating two instances and use the first one only on luma by selecting blend mode lightness and use the second one just for chroma by selecting blend mode color see Section 3 2 6 Blending operators e In an even more elaborate case you could have a module act on different parts of your image As an example you might want to apply a certain gradation curve with module tone curve Section 3 4 2 3 Tone curve to your complete image and have a second curve being applied specifically to skin tones All of the controls offered by drawn masks Section 3 2 7 Drawn mask and parametric masks Section 3 2 8 Parametric mask may be used to select those parts of an image where each of the module instances are applied Please be aware that of course each instance also adds to the workload of your pixelpipe Generating too many instances especially of the more demanding modules
106. dentify our preference These fields are reused when we read the value of the preference The string Field tells the lua engine that the preference is a string It could also be an integer a Filename or any of the types detailed in Section 8 2 2 34 types lua_pref_type We then have the label For the preference in the preference menu the tooltip when hovering over the value and a default value darktable register_storage is the call that actually registers a new storage The first argument is a name for the storage the second is the label that will be displayed in the Ul and last is a Function to call on each image This Function has a lot of parameters but filename is the only one we use in this example It contains the name of a temporary File where the image was exported by darktable s engine This code will work but it has a couple of limitations This is just a simple example after all e We use preferences to configure the target path It would be nicer to add an element to the export Ul in darktable but the lua interface doesn t support this yet Stay tuned e We check the returned value of scp That command might Fail in particular if the user has not correctly set the preference e This script can t read input from the user The remote scp must use password less copy Reading input from the user is doable but beyond the scope of this example e There is no message displayed once the example is done only the progressbar on t
107. dge de tection and results in the characteristic halos around sharp edges in the image This image is the other extreme The wavelet basis now oversharpens which results in ugly gradient re versals near the ridge of the rock Note that the edge parameter only affects the wavelet basis not the image directly You will have to change some denoise contrast boost parameters to see an effect Following adjustments to the edge parameter 91 This module additionally has a mix slider below the spline GUI Adjusting the slider will upscale or downscale the splines on the y axis The slider was added as a convenience tool to help you modify the strength of the effect It is not a module parameter in itself when you leave darkroom mode all changes will be consolidated into the spline curves Have a look at the presets where there are a broad variety of examples that will provide a good starting point to gain an intuitive understanding of the controls Among others there are two presets to enhance an image s clarity 3 4 4 3 Denoise profiled Overview This module offers an easy to use and at the same TE denoise profiled Y time highly efficient denoise operation Under the profile found match for ISO 800 hood it applies your choice of a non local means or oe E edge aware wavelet denoise algorithm with parame strength 1 000 ters specifically profiled for certain camera models blend oft Usage profile mode
108. difference In order to Feel a real difference take modules like shadows and highlights sharpen lowpass highpass or even more extreme equalizer and profiled denoise IF you are interested in profiling Figures you can start darktable with command line para meters d opencl d perf After each run of the pixelpipe you will get a detailed alloca tion of processing time to each module plus an even more fine grained profile For all used OpenCL kernels Besides the speed up you should not see any difference in the results between CPU and GPU processing Except of rounding errors the results are designed to be identical IF For some reasons darktable fails to properly Finish a GPU calculation it will normally notice and automatically and transparently Fall back to CPU processing 9 2 4 Setting up OpenCL on your system 220 The huge diversity of systems and the marked differences between OpenCL vendors and driver versions makes it impossible to give an comprehensive overview of how to setup OpenCL We only can give you an example in this case for NVIDIA driver version 331 89 on Ubuntu 14 04 We hope that this will serve you as a first impression and will help to solve possible problems of your specific setup The principle OpenCL Function Flow is like this darktable gt libOpenCL so gt libnvidia opencl so 1 gt kernel driver module s gt GPU e darktable dynamically links 1ibOpenCL so a system library which must be acces
109. dule _t darktable gui libs hinter The small line of text at the top of the UI showing the number of selected images Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs modulelist The window allowing to set modules as visible hidden Favorite Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs filmstrip The Filmstrip at the bottom of some views Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs viewswitcher The labels allowing to switch view Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs darktable_label The darktable logo in the upper left corner Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs tagging The tag manipulation UI Attributes e has_tostring e parent types dt_lib_ module _t 171 darktable gui libs geotagging The geotagging time synchronisation UI Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs recentcollect The recent collection UI element Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs global_toolbox The common tools to all view settings grouping Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs global_toolbox grouping boolean The current status of the image grouping option Attributes e write darktable gui libs global_toolbox show_overlays boolea
110. e In contrast to blend mode color this mode does not involve clamping color adjustment Some modules act predominantly on the tonal values of an image but also perform some color saturation adjustments e g module levels and tone curve The color adjustment blend mode takes the lightness only from output data and mixes colors from input and output enabling control of the module s color adjustments 3 2 7 Drawn mask Almost all darktable modules have the option to narrow down their effect by a drawn mask and thus allowing local adjustments 3 2 7 1 Overview With the drawn mask Feature you can construct a mask by drawing directly on the image base Different drawing operators called shapes are available and can be used alone or in combination A flexible editing Feature allows you to change single aspects of a shape remove shapes or import shapes already defined in other modules Internally shapes are stored as vector graphics and rendered with the needed resolution during pixelpipe processing Shapes are expressed in the coordinate system of the original image and transformed with all distorting modules This way a shape will always work on the same image area regardless of warping or other modifications that may be applied 3 2 7 2 Usage To draw a shape you need to click on one of the shape blend drawn mask 7 symbols You will automatically be moved into the anaes ea edit mode in which you generate a new instance of Arias 2
111. e We depend on hardware requirements and on the presence of certain drivers and libraries In addition 221 all these have to fit in terms of maker model and revision number IF anything does not fit e g your graphics driver loaded as a kernel module does not match the version of your libOpenCL so OpenCL support is likely not available In that case the best thing to do is start darktable from a console with darktable d opencl This will give additional debugging output about the initialization and use of OpenCL First see if you Find a line that starts with opencl_init FINALLY This should tell you if OpenCL support is available For you or not IF initialization Failed look at the messages above for anything that reads like could not be detected or could not be created Check if there is a hint about where it Failed Here are a few cases observed in the past e darktable might tell you that no OpenCL aware graphics card is detected or that the available memory on your GPU is too low and the device is discarded In that case you might need to buy a new card if you really want OpenCL support e darktable might find your libOpenCL so but then tell you that it couldn t get a plat Form NVIDIA drivers will often give error code 1001 in that case This happens because libOpenCL so is only a wrapper library For the real work Further libraries specific to vendor device and driver need to be loaded This fa
112. e onto another It statistically analyses the color source clusters characteristics of a source image and a target image The colors of the source image are then mapped to corresponding colors of the target image target clusters acquire as source acquire as target number of clusters a 4 color dominance 100 00 histogram equalization blend To use this module two steps are required First you open the source image in darkroom mode and acquire its color characteristics by pressing the acquire as source button Aset of color clusters is generated and displayed in the source clusters area Each cluster is represented by a set of color swatches with the mean value in the center surrounded by swatches indicating the color variance within that cluster The clusters are sorted in ascending order by their weight i e the number of pixels that contribute to the clusters Next you open your target image in darkroom mode darktable has remembered the pre viously collected source clusters if they are not yet displayed press the i button You now press the acquire as target button to generate a corresponding set of color clusters For your target image which gets displayed in the target clusters area When both source and target clusters are collected an automatic color mapping is applied to the target image In its default settings the overall effect is quite exaggerated A set of sliders gives you control of
113. ecial aspect ratios deserve ex planation free Free Forming the rectangle without any ratio restrictions image this option constrains the ratio to be equal to image ratio golden cut this option constrains the ratio to be equal the golden number square this option constrains the ratio to be 1 guides Many self explaining guides are available to help you compose your image Examples A cropped image in center view when module crop jj and rotate is in Focus The cropped area is visible as ALIN J well as some guiding lines t T f PWA P pr Z K Om 3 4 1 2 Orientation 66 Overview This module allows the user to modify the orienta j orientation tion of an image By default it is active For all images and receives its standard settings from the camera s orientation flag stored in the EXIF data Usage rotate Clicking on one of the buttons causes a counter clockwise or clockwise rotation in steps of 90 degrees 3 4 1 3 Shadows and Highlights Overview The shadows and highlights module allows adjust ETJ shadows and highlights Y ment to the tonal range of darker parts of an image shadows 5000 shadows and lighter parts highlights it can bring S an a back details in shadows and highlights by enhancing radius i 100 00 local contrast compress aeee A shadows color adjustment highlights color adjustment blend Usage shadows This slider controls the effect on s
114. eeded to be installed in this specific case were e nvidia 331 331 89 Oubuntu1 xedgers14 04 2 e nvidia 331 dev 331 89 Oubuntu1 xedgers14 04 2 e nvidia 331 uvm 331 89 Oubuntu1 xedgers1 4 04 2 e nvidia libopencl1 331 331 89 Oubuntu1 xedgers14 04 2 e nvidia modprobe 340 24 1 e nvidia opencl dev amd64 5 5 22 3ubuntu1 e nvidia opencl icd 331 331 89 Oubuntu1 xedgers14 04 2 e nvidia settings 340 24 Oubuntu1 xedgers1 4 04 1 e nvidia settings 304 340 24 Oubuntu1 xedgers1 4 04 1 e nvidia libopencl1 331 331 89 Oubuntu1 xedgers14 04 2 e nvidia opencl dev amd64 5 5 22 3ubuntu1 e nvidia opencl icd 331 331 89 Oubuntu1 xedgers14 04 2 e opencl headers 1 2 2013 10 23 1 The list of NVIDIA related kernel modules as reported by 1smod is nvidia nvidia_uvm The list of NVIDIA related device special files 1s 1 dev nvidia should read like crw rw rw 1 root root 195 OO dul 26 214 joev nvidiad Ciw rwe rw 1 FOO root 195 255 dul 28 2113 dev nvidiract 1 Crw rw rw 1 root root 250 0 Jul 28 21 13 dev nvidia uvm Beware that the major minor numbers e g 250 0 for dev nvidia uvmin this example may vary depending on your system 9 2 5 Possible problems and solutions darktable will detect OpenCL run time problems automatically It will then reprocess everything on CPU only speed is affected the Final result should not be endangered There can be various reasons why OpenCL could Fail during initialization phas
115. een and blue there are three sliders lift gamma and gain to control dark tones mid tones and high tones respectively Chang ing these parameters adds offsets to the individual RGB channels and influences the color balance of the image Additional factor sliders act on all colors at once Their effect is similar to the controls of the levels module see Section 3 4 2 2 Levels n a The way to best envision the module s way of working is if you consider lift gamma and gain as parameters influencing the properties of a tone curve which in its original state is a straight line going diagonally from bottom left to top right The lift parameter adjusts the left axis intercept of the line this point can be shifted From its default location with zero abscissa to points with negative or positive ones The gamma parameter modifies the line shape the default shape is linear and can be turned into a convex curve with increased or into a concave curve with lowered gamma values Finally the gain parameter defines the steepness of the curve by default the curve runs diagonally higher values lead to a steeper curve and lower values to a flatter one Side note although this module acts on RGB colors its location in pixelpipe puts it into the Lab color space Accordingly the modules converts from Lab to RGB does its color adjustments and then converts back to Lab Adjusts the value
116. efined closed path Left click into the canvas to define path nodes terminate the path by right clicking after having set the last point Per default nodes are connected by smooth lines IF you want a node to define a sharp corner you can do so by creating it with ctrl click In the edit mode you can convert existing nodes from smooth to sharp corners and vice versa by ctrl clicking on them You can insert additional nodes by ctrl clicking on one of the line segments Single nodes can be deleted by right clicking on them make sure that the mouse pointer is over the desired node and the node is highlighted or else you might accidentally remove the whole path The size of the complete shape can be modified by scrolling analogeous to the circle shape The same holds true for the width of the border i e the area with a gradual opacity decay Single nodes as well as path segments can be moved by mouse dragging IF a node is selected by clicking on it a Further control point appears you can move it around to modify the curvature of the line Dragging one of the control points on the border adjusts the border width just in that part of the shape Consider to finetune a path in the restricted edit mode see above which allows you to adjust single nodes and segments without the risk of accidentally shifting or resizing the whole shape A path shape with controls and activated mask dis play Clicking the Bi symbol adds a gradient to
117. eft and right borders of the histogram after having applied the black point and white point corrections only automatic mode Sets the white point in percentiles relative to the right border of the histogram only au tomatic mode 3 4 2 3 Tone curve Overview Usage 76 This module is a classic digital photography tool Un gt 0 tone cuve Y like other image manipulation software however aa s darktable s tone curve acts in Lab color space Thus it offers three independent curves for L a and b chan nels In its default state curves will be straight lines defined by few anchor nodes You can move the nodes with your mouse to modify the curve You can also generate new nodes by clicking on the curve Up to 20 nodes per curve can be defined To remove a node move it out of the widget area A color picker is activated by pressing i and will show the picked values in the graph Numerical Lab values of input and output see below at the selected spot are shown on top left of the widget L channel curve The tone curve in L channel works on Lightness For a better overview a lightness his togram is displayed in the diagram The horizontal line represents the input image pixels lightness The vertical line repre sents the lightness of the output image pixels A straight line does not change anything A point above the default diagonal increases the lightness whereas a point under decreases it Shifting t
118. either nilor a string The result will be passed back as the result of the DBus method IF the Lua call results in an error the DBus method call will return an error org darktable Error LuaError with the lua error message as the message attached to the DBus error 8 1 8 Using Darktable from a lua script Warning This feature is very experimental It is known that several elements don t work in library mode yet Careful testing is highly recommended The lua interface allows you to use darktable from any lua script This will load darktable as a library and provide you with most of the lua API darktable is configured headless so the Functions related to the user interface are not available As an example the following program will print the list of all images in your library usr bin env lua package require package package cpath package cpath lib darktable lib so dt require darktable Wes LID rar yg sd eo ve ty ab _ datadir share darktable moduledir lib derktable Meson toda gt af CONELGGEr Ne CacneGir Cached Q Latal wernangs require darktable debug for k v in ipairs dt database do print Costring v end Note the third line that points to the location of the libdarktable so file Also note that the call to require returns a function that can be called only once and allows you to set darktable s command line parameter The memory parame
119. eld wait_ms 2000 wnikle Crue do dt gui libs tested_module visible not dt gui libs tested_module visible coroutine yield wait_ms 2000 end darktable gui libs snapshots The Ul element that manipulates snapshots in darkroom 169 Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs snapshots ratio number The place in the screen where the line separating the snapshot is Between 0 and 1 Attributes e write darktable gui libs snapshots direction types snapshot_direction_t The direction of the snapshot overlay Attributes e write darktable gui libs snapshots types dt_lua_snapshot_t The different snapshots for the image darktable gui libs snapshots selected The currently selected snapshot darktable gui libs snapshots take_snapshot function Take a snapshot of the current image and add it to the UI The snapshot file will be generated at the next redraw of the main window darktable gui libs snapshots max_snapshot number The maximum number of snapshots darktable gui libs styles The style selection menu Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs metadata_view The widget displaying metadata about the current image Attributes e has_tostring 170 e parent types dt_ lib module _t darktable gui libs metadata The widget allowing modification of metadata Fields on the current image Attributes e has_tostring e parent types dt_lib_ mo
120. elected images You will be prompted For which items to include This button is greyed out until a history stack is copied from another image paste all Paste all previously copied items of a history history stack onto all selected images This button is greyed out until a history stack is copied from another image load sidecar file Opens a dialog box to select an XMP file thus loading a history stack that you can paste on images Files that were exported by darktable typically contain the full history stack if the file format supports embedded metadata see Section 2 3 12 Export selected about this feature and its limitations You can load an exported image as a sidecar file in the same way as you do with an XMP file This Feature allows you to recover all parameter settings in case you have accidentally lost or overwritten the XMP file All you need is the source image typically a RAW and the exported file write sidecar files Write XMP sidecar files for all selected images The filename is generated by appending xmp to the name of the underlying input file By default darktable generates and updates sidecar files automatically whenever you work on an image and change the history stack You can disable automatic sidecar file generation in the preferences dialog see Section 7 2 Core options However this is not recommended 2 3 8 Styles 29 This panel provides a powerful Functionality in dark styles
121. enaen a a ARENAN 133 Gle OVEIVICW oea A ETA a a AS 134 6 2 USE ana a a Nas cll wine aliens gates eins ail as 135 TaPrelerences and settings seisnesid a ea 137 FAISG ULODLON S ieo a a A A sa noua merce A ANa 138 Teee COME OD CIOS aeree E a aA 141 P38 SCSSION ODU ON S eano e hak eins rete he hae eh a cera ical Dien ne 143 TAr SION CUES aeset eats reactants tena neuen aa Noa ne raion a sumac Ronan ake 145 Lar PECSCES soos gia tecnica achat trials eau hota alta tend cae ie te A bite ateaiauundcss 148 Be SCHON GN ESI aaa aa fusetoaa anda ciated a A ton tua need 151 8 Te EUT USI ge ron ee eee ee eee 152 P LT BaSe DRMCIDLCS onice Ns tasted once a sent ach a Sateunceemicaaess 152 8 122 AcSiMmplelUa example nia e A ASE 152 Bloc Printing labeled IMAGES ercon a a a 152 8 1 4 Adding a simple shortcut sesesesesesesesesesesssesesesesesesssseseeesesesesese 154 8 125 EXPOFEING images WIEN LW ecs ar a AS 156 B tO SMNI SOD CS eieaa 157 8 1 7 Calling Lua from D BUS santanna a A 159 8 1 8 Using Darktable from a lua script s sssssssssssssesesesesesesesesesesesesese 159 9 2 LUS API eoa a A A AS 160 ELE EAE 8 ANE PTEE OE EEI EEE EA AE T E E T 160 SLOE D EA EEE E E EET E E EEA E E E ee A AN 188 Beo EVEN nna a aa aa a a oe Soeieae ce 209 B2 Arat DUCE Snia a N AA 213 82o SVS e aea aa a a ASN 213 De SpeciIt TOpiCS sissa e A a A 215 9 darktibDleand MEMORY metiosndist taiea niecne a eni 216 OA 1 TOCALSYSECM MEMORY ainia A A 216 9 1 2
122. ending on the opacity value it reduces the strength of a module s effect Generally this is also the blend mode of choice if you want to apply a module s effect locally using masks normal bounded lightness chroma hue color This blend mode acts similarly to blend mode normal except that input and output da ta are clamped to a particular min max value range Out of range values are effectively blocked and do not pass to the following modules Sometimes this helps to prevent arti Facts However in most cases e g highly color saturated extreme highlights it is better to let unbound values travel through the pixelpipe in order to properly deal with them at the right place e g in module output color profile Blend mode normal is most often the preferred choice This blend mode mixes lightness from the input and output images Color data chroma and hue are taken unaltered from the input image This blend mode mixes chroma saturation from the input and output images Lightness and hue are taken unaltered from the input image This blend mode mixes hue color tint from the input and output images Lightness and chroma are taken unaltered from the input image Caution When modules drastically modify hue e g when generating complementary colors this blend mode can result in strong color noise This blend mode mixes color chroma and hue from the input and output images Light ness is taken unaltered From the i
123. era or control the camera From within darktable in teth ering mode no supported devices found Imported images are organized as film rolls see Section 2 2 1 Film rolls All Film rolls are accessible through the collect images module see Section 2 3 2 Collect images IF you set the selection attribute to Film roll you get a list of available Film rolls which can be filtered using the editbox to quickly Find the one of interest Double click on a film roll in the list and it will open in the lighttable You can also click the items in recently used collections see Section 2 3 3 Recently used collections to open the latest ones you have worked with 2 3 1 1 Import from Filesystem 22 You can import either a single image or a Folder The imported image s will show up in a Film roll with the name of the filesystem Folder Clicking on image or folder opens a File selector dialog Navigate through the filesys tem and select the item to import On the lower part of the dialog are some Further im port options As the name implies checking import directories recursively will import images in the currently selected directory and all subdirectories It is not recommended and wastes resources to do this on an exhaustive list of images darktable would generate thumbnails For all of them but in the end only keep the recent ones in its cache It is better to import images in smaller chu
124. es IF you don t want to distribute history stack data with your images there are various tools to delete embedded XMP tags As an example you can use the program exiftool http www sno phy queensu ca phil exiftool with exiftool XMP all image jpg Set the maximum width and height of the output images in pixels Set both to a value of 0 to export with Full resolution darktable currently can only do down scaling the maximum output resolution is defined by the parent image Caution it s a frequent pitfall to accidentally put low values like 1 or 10 in these fields causing darktable to produce miniature output files You might think darktable s output is broken but in fact it only generated what you asked for This option lets you define the intent i e the way darktable will deal with out of gamut colors See Section 3 4 3 3 Output color profile for a more detailed description of the available options This defines the output color profile Select image settings if you want the settings in the output color profile see Section 3 4 3 3 Output color profile module of the individual images to take precedence This option lets you choose a style i e a collection of history stack items which darktable concatenates with the existing history stack to generate the output image These history items are only added temporarily the original history stack is not overwritten You can use this Feature to add process
125. es are brought to you by Federico Bruni Victor Lamoine and Michel Leblond Many thanks to all contributors to this user manual Special thanks for proof reading style improvement constructive criticism and valuable contributions go to Colin Adams Mark Garrow Simon Harhues Istvan Kovacs Michel Leblond Rudolf Martin Ammon Riley Rob Z Smith Andrew Toskin and David Vincent Jones Vil viii Chapter 1 Overview darktable is an open source photography workflow application and RAW developer a vir tual lighttable and darkroom for photographers It manages your digital negatives in a database lets you view them through a zoomable lighttable and enables you to develop raw images and enhance them General Features e darktable runs on GNU Linux GNOME Mac OS X macports and Solaris 11 GNOME e Fully non destructive editing e All darktable core Functions operate on 4x32 bit Floating point pixel buffers for high accuracy processing preventing banding and color breaks e darktable makes heavy use of Streaming SIMD Extensions 2 SSE2 instructions of the CPU to speed up processing In Fact darktable will only run on a CPU that supports SSE2 e GPU acceleration via OpenCL runtime detection and enabling e Most image processing is done in CIELab color space which is much larger than the gamut of modern displays printers or even human vision e Full color managed display with softproofing and gamut check Built in ICC
126. espec tively Marking a module as a Favorite is done in the more modules dialog Section 3 3 8 More modules at the bottom of the right panel by clicking a module until a star is dis played in Front of the icon 1 3 2 2 White balance The white balance module controls the white balance or color temperature of the image It s always enabled and reads its default values from camera metadata embedded in the image The most common change is fine tuning the white balance which is done using the temperature slider Moving this slider left will make the color balance cooler and moving it right will make it warmer 1 3 2 3 Exposure correction The exposure module is probably the most basic module of them all Exposure is fine tuned either by using the slider or by dragging with the mouse in the histogram You can also boost the black level to enhance contrast but be careful use small amounts like steps of 0 005 There is also an auto correct Feature 1 3 2 4 Noise reduction The best starting point for noise reduction is profiled denoise This module offers an almost single click solution to Fight noise From a user perspective the effect only depends on camera type and ISO value both derived From EXIF data All other settings are taken from a database of noise profiles that the darktable team has collected now covering already over 100 popular camera models In addition you have several other options in darktable to
127. events post import image extra registration parameters This event has no extra registration parameters 210 8 2 3 3 events shortcut event This event registers a new keyboad shortcut The shortcut isn t bound to any key until the users does so in the preference panel The event is triggered whenever the shortcut is triggered This event can only be registered once per value of shortcut events shortcut callback PUI E Hort event string SHORECUG E Seri event SErING The name of the event that triggered the callback shortcut String The tooltip string that was given at registration time events shortcut extra registration parameters tooltip String The string that will be displayed on the shortcut preference panel describing the shortcut 8 2 3 4 events post import film event This event is triggered when an film import is Finished all post import image callbacks have already been triggered This event can be registered multiple times events post import film callback TUnCE LON event string Padi CypesSy dt lua Crimi event Se rang The name of the event that triggered the callback 211 Film types dt_lua_film_t The new film that has been added IF multiple Films were added recursively only the top level Film is reported events post import film extra registration parameters This event has no extra registration parameters 8 2 3 5 events view changed event This event is triggered a
128. eview image and thumbnails have a low resolution and can be processed quickly center image view is more demanding let alone the pixelpipe doing a file export IF you have a reasonably fast GPU and want to get a low latency during interactive work it is therefore important that your GPU is allocated to do the more demanding center image Full pixelpipe while the smaller preview image can be processed in parallel by the CPU Older versions of darktable would therefore not allow the preview pixelpipe to grab any OpenCL device Starting with darktable 1 2 there is a more flexible scheme to allocate and prioritize your OpenCL device s Configuration parameter opencl_device_priority holds a string with the Following structure yO pC sin a5 Kp pS as Op Oa ace a Vi ees Each letter represents one specific OpenCL device There are four fields in the parame ter string separated by a slash each representing one type of pixelpipe a b c defines the devices that are allowed to process the center image Full pixelpipe Likewise devices k lm can process the preview pixelpipe devices o p q the export pixelpipes and Finally devices x y z the thumbnail pixelpipes An empty field means that no OpenCL device may serve this type of pixelpipe 225 226 darktable has an internal numbering system where the first available OpenCL device will receive number O All Further devices are numbered consecutively This
129. exist multiple thumbnail caches in parallel one for each library File localedir lt locale directory gt The place where darktable finds its language specific text strings The default place depends on your installation Typical places are opt darktable share locale and usr share locale luacmd lt lua command gt A string containing lua commands to execute after lua initialization These commands will be run after your luarc File IF lua is not compiled in this option will be accepted but won t do anything conf lt key gt lt value gt darktable supports a rich set of configuration parameters which the user defines in darktablerc darktable s configuration File in the user config directory You may temporarily overwrite individual settings on the command line with this option how ever these settings will not be stored in darktablerc 1 1 2 darktable cli binary This binary starts the command line interface variant of darktable which allows exporting images darktable c1li is called with the following command line parameters darktable cli lt input file gt lt xmp file gt lt output file gt width lt max width gt height lt max height gt bpp lt bpp gt hgq lt 0 1 true false gt verbose core lt darktable options gt The user needs to supply an input Filename and an output Filename All other parameters are optional lt input File gt
130. f types dt_lua_image_t high_quality boolean extra_data table 163 jc oF table or nil A function called before storage happens This function can change the list of exported functions storage types dt_imageio_module_storage_t The storage object tested format types dt_imageio_module_format_t The format object to report about images table of types dt_lua_image_t A table containing images to be exported high _quality boolean True if the export is high quality extra_data table An empty Lua table to take extra data This table is common to the initialize store and finalize calls in an export serie return table or nil The modified table of images to export or nil IF nil or nothing is returned the original list of images will be exported IF a table of images is returned that table will be used instead The table can be empty The images parameter can be modified and returned 8 2 1 5 darktable films A table containing all the Film objects in the database darktable films types dt_lua_film_t Each film has a numeric entry in the database darktable films new 164 function GiLCCLOLY Stl ring types dt lua ti lint Creates a new empty Film see darktable database import to import a directory with all its images and to add images to a Film directory Sting The directory that the new film will represent The directory must exist return types dt_lua_film_t The newly created film or the existing F
131. ft right top and bottom to the center area The left panel typically has an informational purpose The right panel offers functions to modify an image The top and bottom panel give access to several settings and shortcuts Each of the panels can be collapsed or expanded by pressing a triangle like aj located close to the panel By pressing the TAB key all panels get collapsed allowing the center area to occupy all available space Pressing TAB again brings you back to the previous view Fullscreen view can be toggled by pressing F11 darktable s contrast can be changed by using F7 and F8 and darktable s lightness by using F9 and F10 1 2 3 Filmstrip The filmstrip along the bottom shows the same images as lighttable with respect to filters and sort order It is turned on off with key accelerator ctrl f You can navigate along the Filmstrip by scrolling with the mouse wheel The Filmstrip allows you to interact with im ages while you are not in lighttable mode For example you can while developing an im age in darkroom mode switch to another image to develop by double clicking the thumb nail in the Filmstrip You can also rate the images as you do in lighttable copy paste his tory stack etc 1 2 4 Preferences A button Ed located in the upper panel allows you to define various parameters which con trol darktable s behavior The options are Fairly self explanatory IF you need more information hover the mouse cursor
132. fter the user changed the active view events view changed callback Fumie e Om old_view types dt_view_t new_view types dt_view_t old view types dt_view_t The view that we just left new_view types dt_view_t The view we are now in events view changed extra registration parameters This event has no extra registration parameters 8 2 3 6 events global_toolbox grouping_toggle event This event is triggered after the user toggled the grouping button events global_toolbox grouping_toggle callback Tuner Lon toggle boolean toggle boolean the new grouping status 212 events global_toolbox grouping_toggle extra registration parameters This event has no extra registration parameters 8 2 3 7 events global_toolbox overlay_toggle event This event is triggered after the user toggled the overlay button events global_toolbox overlay_toggle callback function toggle boolean toggle boolean the new overlay status events global_toolbox overlay_toggle extra registration parameters This event has no extra registration parameters 8 2 4 attributes This section documents various attributes used throughout the documentation 8 2 4 1 attributes write This object is a variable that can be written to 8 2 4 2 attributes has_tostring This object has a specific reimplementation of the tostring method that allows pret ty printing It 8 2 4 3 attributes implicit_yield This call will release the Lua lock while execut
133. g Mouse scrolling while holding the control key pressed gives an extended zoom range between 2 1 and 1 10 You normally export multiple images from the lighttable view but you can also export the current image directly From the darkroom by using the shortcut ctrl e Export parameters are then those currently selected in the lighttable 3 2 Darkroom concepts This section tries to explain some of the basic concepts on how darktable develops images in the darkroom The basic element of an image operation in darktable is called a module darktable comes with a rich set of over 50 modules for all kind of image manipulations In Section 3 4 Mod ules you will Find a description for each of the available modules 3 2 1 Pixelpipe module order and history stack darktable processes images From input to output in a so called pixelpipe Within the pixelpipe image processing consists of consecutive operations which are implemented as modules Modules are applied in a Fixed order This differentiates darktable as a non destructive image editor From classical image manipulation programs like The Gimp As module order is Fixed you are free to activate deactivate or change the parameters of a module at ar bitrary points in time the order of activation in your workflow does not have any impact on the outcome Users Frequently ask why the module order is Fixed and if there are plans to change that restriction There are se
134. g them clear this rule Removes this rule or resets to default if this is the only rule defined narrow down search Adds a new rule which is combined with the previous rule s in a logical AND operation An image is only part of the collection if it additionally fulfills the added rule add more images Adds a new rule which is combined with the previous rule s in a logical OR operation Images that Fulfill the new rule are added to the collection 25 exclude images Adds anew rule which is combined with the previous rule s in a logical EXCEPT operation Images which are selected by the new rule are exempted From the collection combining rules The logical operators defining the combination of rules are displayed to the right of the rule AND by the Ml symbol OR by the M symbol and EXCEPT by the symbol Clicking on either symbol gives a choice to change the logical operation 2 3 3 Recently used collections This panel keeps track of the latest collections you have used so you can jump to recently used collec tions without remembering what rules were speci Fied in the collection 2 3 4 Image information This panel shows information embedded within an image s EXIF data When hovering with the mouse over thumbnails darktable will update this view dis playing information of the image currently under the mouse cursor This panel is also available in dark room tethering and map view 2 3 5 Select Th
135. g when importing images default none publisher to be applied when importing IF provided automatically add this string as a publisher tag when importing images de Fault none rights to be applied when importing IF provided automatically add this string as a copyrights tag when importing images de Fault none 138 comma separated tags to be applied when importing IF you want to add further tags when importing images you can give them as a comma separated list default none initial import rating Initial star rating From 0 to 5 for all images when importing a Film roll default 1 enable Filmstrip Enable the Filmstrip in darkroom tethering and geomapping modes default on maximum width of image drawing area Maximum width of the image drawing area in darkroom mode adjust to your screen Needs a restart and will invalidate current thumbnail caches default 1300 maximum height of image drawing area Maximum height of the image drawing area in darkroom mode adjust to your screen Needs a restart and will invalidate current thumbnail caches default 1000 compression of thumbnail images Controls the compression of thumbnail images in memory and on disk Options off low quality Fast high quality slow default off pen pressure control for brush masks Controls how the pressure reading of a graphics tablet impacts newly generated brush strokes see Section 3 2 7 Drawn mask
136. ge target storage Where to store your selected images Different back ends are implemented including File on disk a LaTeX book template and various web albums Depending on the selected tar get you will be asked to give additional information like Filenames or account name and password Filename template You can define Filenames that darktable generates for export Several pre defined vari ables can be used as placeholders S ROLL_NAME roll of the input image S FILE_FOLDER Folder containing the input image S FILE_NAME basename of the input image 33 FILE_EXTENSION VERSION extension of the input image the duplicate version see Section 2 2 7 Sidecar files a sequence number within export job S YEAR year at date of export S MONTH month at date of export S DAY day at date of export S HOUR hour at time of export S MINUTE minute at time of export S SECOND second at time of export S EXIF_YEAR exif year S EXIF_MONTH exif month EXIF_DAY exif day S EXIF_HOUR exif hour S EXIF_MINUTE exif minute S EXIF_SECOND exif second S STARS star rating S LABELS colorlabels S PICTURES FOLDER pictures Folder S HOME home Folder S DESKTOP desktop folder output directory Pressing button li opens a dialog to select the parent directory for export overwrite Enabling the amp checkbox allows darktable to overwrite existing images during export IF this option is not checked darktable automati
137. ge types dt_lua_image_t The image to move Film types dt_lua_film_t The Film to move to darktable database copy_image Puneet Tent image types dt_lua_image_t fidm types dt lua ifm ct types dt_lua_image_t Physically copies an image to another Film This will copy the image File and the related XMP to the directory of the new film IF there is already a File with the same name as the image file it wil create a duplicate From that File instead Note that the parameter order is not relevant image types dt_lua_image_t The image to copy Film types dt_lua_film_t The film to copy to return types dt_lua_image_t The new image 186 darktable database delete see types dt_lua_image_t delete 8 2 1 14 darktable debug table This section must be activated separately by calling require darktable debug darktable debug dump FUNCT Ons object anything name string known table l 2 Sr eng This will return a string describing everything Lua knows about an object used to know what an object is This Function is recursion safe and can be used to dump _ Gif needed object anything The object to dump name string A name to use for the object known table A table of object string pairs Any object in that table will not be dumped the string will be printed instead defaults to darktable debug known if not set return SCring A string containing a text description of the object can be very long d
138. ges see Section 2 3 5 Select and then press the corresponding color button in the bottom panel To remove all labels From the selected images press the grey button 2 2 5 Filtering and sort order The Filtering and sort order of images in the light view oo table view are controlled in the top panel rejected only all except rejected With filtering you limit the number of displayed images in your current collection see also Section 2 3 2 Collect images Filtering is mainly based on the star ratings of your images A typical filtering rule will show all images that have a rating at or above the given number of stars from one to Five The comparison operators is not restricted to 2 By UAT M uU mM u clicking on the operator field you toggle between 2 gt lt lt and Alternatively you can make darktable display all images only the unstarred ones only the rejected images and all but the rejected ones Images in the lighttable view can be displayed in different sort orders depending on file name time when the photo was taken rating i e stars id an internal ordering number of darktable or color labels You can sort in reversed order by toggling the tri angle button to the right of the sort by combobox 2 2 6 Image grouping 18 Grouping images helps improve structure and clarity of you
139. ges is too high threshold Sets the threshold over which the edge of a pixel is counted as a fringe The colors of the affected pixels will be rebuild from neighboring pixels Try lowering this value if there is not enough Fringe detected and try increasing this value if too many pixels are desatu rated You may additionally want to play around with the edge detection radius 3 4 5 Effect group 100 In the effect group you will Find modules with a more artistic touch 3 4 5 1 Watermark Overview The watermark module provides a way to render a O 08 watermark vector based overlay onto your image Watermarks marker daritable svg are standard SVG documents and can be designed us opacity 100 ing Inkscape http www inkscape org scale 100 A rotate 0 00 s scale on image alignment x offset 0 000 y offset 0 000 blend off Y The SVG processor of darktable also substitutes strings within the SVG document which gives the opportunity to include image dependent information in the watermark such as aperture exposure time and other metadata User designed watermarks are placed into the directory SHOME config darktable water marks Once in place use the reload button at the right of the watermark file name to update the list of available watermarks to use Here Follows a list of available variable strings that is supported for substitution within the svg document DARKTABLE NAME DARKTA
140. ghts The rights assigned to the image Usage marker Choose the watermark of interest You can use the reload button next to the combobox to update the list with all newly added watermarks opacity Set the opacity of the watermark s rendering scale Scale the watermark pixel independently rotate Set the rotation angle of the watermark scale on Defines the reference For the scale parameter The default setting image scales the wa termark relative to the horizontal image size Alternatively you can scale the watermark relative to the larger border and smaller border respectively alignment Use these controls to align the watermark to any edge or center of the image x offset Pixel independent offset relative to the choice of alignment on the x axis y offset Pixel independent offset relative to the choice of alignment on the y axis 3 4 5 2 Framing 102 Overview This module is an artistic Feature to generate a frame 2008 framing Y around your image The frame consists of a border border size 10 00 with a user defined color and a frame line inside that fi hen mie Or border which has another user defined color There horizontal posttion center 7 are various options for you to control the geometry ESA N of your frame frame ine offset F 50 00 border color ied frame line color Fad Usage border size This slider controls the size of the Frame in percent of the underlying Full image aspect Wit
141. h is the sensor used in the majority of cameras 3 4 4 14 Defringe Overview This module is designed to remove purple or any oth 2008 defringe er color of fringing which often results From Longi operation mode local average slow 7 tudinal Chromatic Abberations LCA also known as 2 Axial Chromatic Abberations ee pees Usage This module helps removing fringe via edge detection Where pixels are detected as a Fringe it rebuilds the color from lower saturated neighboring pixels operation mode Set the operation mode for detecting Fringes global average is usually the Fastest but might show slightly incorrect previews in high magnification It might also protect the wrong regions of color too much or too little by comparison with local averaging local average is slower because it computes local color references For every pixel which might protect color better than global average and allows for rebuilding color where actually required The static method does not use a color reference but directly uses the thresh old as given by the user edge detection radius Set the spatial extent of the gaussian blur used for an edge detection The algorithm uses the difference of gaussian blurred and original image as an indicator for edges a special case of the difference of gaussians edge detection Try increasing this value if you either want a stronger detection of the Fringes or the thickness of the Fringe ed
142. h this combobox you can choose between different aspect ratios For the Final output of this module i e underlying image plus Frame orientation IF you select a non square aspect ratio this combobox defines the orientation portrait or landscape Set to auto if you want darktable to select the most reasonable orientation based on the underlying image horizontal position Select from a set of pre defined ratios where you want your underlying image be posi tioned on the horizontal axis You can also right click and enter your own ratio as x y vertical position Select From a set of pre defined ratios where you want your underlying image be posi tioned on the vertical axis You can also right click and enter your own ratio as x y Frame line size The percentage of the frame line size relative to the border size at its smallest part Frame line offset Where the Frame line is positioned relative to the underlying image Select a value of 0 For a Frame line touching the image 100 for a Frame line touching the outer border limits border color Clicking on the colored Field will open a color selector dialog which allows one to define a color for the border in HSL or RGB color space You can also activate a color picker by pressing i and take a color probe from your image Frame line color Clicking on the colored Field will open a color selector dialog which allows one to define a color for the frame in HSL o
143. hadows positive values will lighten up shadows while negative values will darken them highlights This slider controls the effect on highlights negative values will darken highlights while positive values will lighten them up soften with This combobox chooses the underlying blurring filter gaussian or bilateral Try bilateral Filter if you experience halos with gaussian blur radius This slider controls the radius of the involved blurring filter Higher values give softer tran sitions between shadows and highlights but might introduce halos Lower values will re duce the size of halos but may lead to an artificial look As said bilateral Filter is much less prone to halo artifacts compress This slider controls how strong the effect extends to midtones high values reduce the ef Fect to the extreme shadows and highlights low values cause strong adjustments also to 67 midtones You normally only need to touch this parameter if you want to limit the effects to the extreme shadows and highlights increase the value in this case At 100 this mod ule has no visible effect any longer as only absolute black and absolute white are affected shadows color adjustment This slider controls the color saturation adjustment made to shadows high values cause saturation enhancements on lightened shadows low values cause desaturation on light ened shadows It is normally safe to leave this at its default of 100 This gives a natural
144. hat excludes the red petals The small white bar in the gradient was obtained by using the L color picker on one of the petals and the markers quini then closely centered on the indicated hue to in S crease the selectivity of our mask 7 mask blur The resulting blend mask The Final image after module monochrome is applied 3 2 9 Combining drawn and parametric masks This section describes how darktable combines individual masks to Form the Final mask of a module Individual masks are the drawn mask and all the single channels of the parametric mask The topic is rather advanced if you don t want to go through all the theoretical details just jump down where we describe two typical use cases 3 2 9 1 Overview There are two main elements which control how individual masks are combined the po larity setting of each individual mask defined by the plus or minus buttons and the set ting in the combine masks combobox see Section 3 2 5 Blending Masks can be regarded as grayscale images which take up values between 0 and 1 0 or From 0 to 100 for each pixel A straightforward way to combine masks is by multiplying the individual pixel values The Final mask will have a pixel value of 0 whenever one of the individual masks is O at that pixel location The Final mask can only reach a maximum pixel value of 1 0 if each and every of the individual masks has a value of 1 0 at that location We call this way
145. he lower left side tells the user that the job is done e We use coroutine yield to call an external program The normal os execute would block other lua codes from happening 8 1 6 Sharing scripts So far our lua code was in luarc That s a good way to develop your script but not very practical for distribution We need to make this into a proper lua module To do that we save the code in a separate file scp storage lua in our case all SCP STORAGE a simple storage to export images via scp AUTHOR 157 158 J r my Rosen jeremy rosen enst bretagne fr INSTALATION copy this file in SCONFIGDIR lua where CONFIGDIR 1s your darktable configuration directory add the following line in the file S SCONFIGDIR luarc require scp storage USAGE set the target directory for scp in preferences gt lua gt target SCP path select Export via SCP in the storage selection menu export your images LICENSE GPLv2 darktable require darktable darktable configuration check_version 3 0 0 darktable preferences register scp_export export_path String target SCP path Complete path to copy to Can include user and hostname darktable register_storage scp_export Export via scp function storage image format filename number total high_gquality extra data ift coroutine yield RUN_COMMAND scp filename Tau darktable preferences read scp_export Wexpo
146. he center of the curve upwards will lighten the image shifting it downwards will darken the image An S like curve will enhance the contrast of the image a b channel curves The curves in the a and b channels work on color values They are only displayed and active if the scale chroma combobox is set to manual The horizontal line represents the color channel value of the input image pixels The vertical line represents the color channel value of the output image pixels Positive a values correspond to more magenta colors negative a values correspond to more greenish colors Positive b values correspond to more yellowish colors negative b values correspond to more blueish colors A straight line does not change anything Shifting the center of the curve will give the image a color tint shifting a channel upwards gives a magenta tint shifting b channel up wards gives a yellow tint shifting a channel downwards gives a green tint shifting b chan nel downwards gives a blue tint Increasing decreasing the steepness of the curves without shifting its center will in crease decrease the color saturation of the respective channel With properly defined curves you can exert fine control on color saturation depending on the input pixel s colors scale chroma darktable does an automatic adjustment of color saturation if this combobox is set to au to The level of this adjustment depends on the pixel s color values and its L value m
147. heir neighbors Usage You control the detection sensitivity with the threshold parameter and the level of elim ination with the strength parameter threshold The threshold of the detection i e how strong a pixel s value needs to deviate From its neighbors to be regarded as a hotpixel strength The strength of blending hotpixels with their surrounding detect by 3 neighbours This will extend the detection of hotpixels it will even regard a pixel as hot if a minimum of only three instead of four neighbor pixels deviate by more than the threshold level mark Fixed pixels This options will mark the pixels that have been corrected It also displays the count of detected and Fixed pixels 3 4 4 13 Chromatic aberrations Overview This module allows you to correct chromatic aberra D chromatic aberrations tions automatic chromatic abe ion correction 99 Usage The module has no parameters On activation it will automatically try to optimize away visible CA s The underlying model assumes as input an uncropped photographic image The module is likely to Fail when you zoom into the image as in that case it will only receive parts of your photograph as input in darktable s pixelpipe As a consequence chromatic aberrations do not get corrected properly in the center view This limitation only applies to interactive work not to file export This module currently only works for images recorded with a Bayer sensor whic
148. hown while you cap ture them You can get an exposure by either us ing darktable s userinterface or manually triggering a capture on your camera IF you are using LiveView it will be shown in darktable s center view When entering tethering view a Film roll will be created using the same structure as de Fined when you import from the camera Job code will be predefined as capture IF you want to group your captures into different film rolls you should use the session panel in right side When entering a new name and pressing enter a new film roll will be created and captured images will go into this new film roll darktable provides some nifty tools to setup a capture in the user interface You can setup timelapse captures and brackets for HDR creations The configuration is so dynamic that you can create sequential capture of brackets go figure For more information read the documentation about the capture panel and the examples in this chapter 4 2 Tethering panels This section contains documentation for panels that are specific to the tethering view 4 2 1 Session A session is a sequence of exposures taken in tether ing mode and going into a single Film roll A new ses sion equals a new film roll A film roll is created with the same storage structure that is used when you im port images from camera into darktable It s a bit awkward but configuring this storage struc ture is done in the camera import dial
149. ht reconstruction 72 highpass 108 histogram 61 history stack 28 39 57 hotpixels 99 image information 26 import 22 HDR files 24 LDR Files 24 RAW files 24 input color profile 88 invert 74 L lens correction 94 levels 75 lighttable panels collect images 24 export 33 geo tagging 30 history stack 28 image information 26 import 22 metadata editor 32 recently used collections 26 selected images 27 selecting images 26 styles 29 tagging 32 lighttable view 13 local adjustments 47 local contrast 79 see also equalizer local copies 21 28 lowlight 110 lowpass 108 Lua 151 Lua API 160 164 170 175 182 185 202 203 204 action_images 166 api_version_major 178 api_version_minor 178 230 api_version_patch 178 api_version_string 179 api_version_ suffix 178 apply 184 203 apply_style 188 attach 176 204 attach_tag 188 attributes 213 backgroundjobs 175 blue 192 bpp 196 196 198 cache_dir 178 callback 209 210 211 211 212 212 213 camera 175 check_version 179 collect 173 colorlabels 173 colorpicker 174 compression 197 comp_ltype 198 comp _ type ft 208 configuration 177 config_dir 178 copy 189 copy_history 173 copy_image 186 202 coroutine 213 create 176 182 create_job 167 create_style 188 creator 190 current_view 167 darkroom 169 darktable 160 darktable_ label 171 database 185
150. ialogue to include or exclude specific items from the stack Check option duplicate if you want to create a new style instead of overwriting the existing one you need to provide a new unique style name in this case delete This deletes the selected style without Further question import You can import a style which has been previously saved by darktable darktable stores styles as XML files with the extension dtstyle export This option saves a selected style to disk as a dtstyle file This allows publishing styles and sharing styles with other users 2 3 9 Geotagging 30 Use this panel to import and apply GPX track data on geotagging a selection of images Alternatively you can manually aur 00 00 00 a ey geotag images within the Map view see Chapter 5 apply gpx track file Map 2 3 9 1 Usage A GPS receiver calculates its current position based on the information it receives from satellites and records them in a GPX file together with the current date and time The EXIF data of the images also contains a time stamp defined by the camera settings dark table takes the time stamp of the image looks up the position in the GPX file at that time and stores the coordinates latitude longitude in its database and the image s XMP side car file There may occur two problems In contrast to GPS devices most cameras don t record the accurate time Secondly the time stored in the EXIF data doesn t cont
151. ic WORK lOW sisis sndivecsswercscetiundssussuder cess ulessuusbanstetiucdseunsubesceweuede 8 132 AM POLCING HMA GOS ain e cases Gongs viteaedd a Gouses teers ae 8 1 3 2 Basie development SEC DS suriin e woke tara a a a saa etei 8 1359s EXPONO IMa GES uona a a a E E T 10 2o LIN tCa Dle eain aaa e a a a a a a a a a E a EE loess te 13 AN OVERVICW sdra eaaa a a a a a 14 22 HONECADIE CONCEDES arinei e a eiei 16 D2 Ne PUT TOUS inea a a EE E E 16 2 22e COlECCONS ceee aeea n eie Amro a A a a e ai 16 22s TUMON lS ueria a A aa a a a oasaeed 16 2 2 4 Star ratings and color labels aorin a AEA 17 2 25 FILELING and Sort OG ON arnie a a E T 18 2 26 MAGE GrOU DING srnec a aa a aa o n 18 22 odeca eS aaa a T 19 2 2 8 Importing sidecar files generated by other applications 0 20 22 LOL COD ES ane a siete E a A aa reas ea 21 2 3 EIGMECAD LE Panels snena e E A e ei a Eea 22 2a Wes MD O RG casia e a A A E E a bakers 22 2 32 COlect image Sna enen ea e e aa E E a 24 2 3 3 Recently used collections sseni enaa a aa 26 2 3 4 Image INFOMATION eieiei e e a a a ea aa e a E 26 DBs DONC E E A E E E E E E E A A E E 26 253 0 Selected Image S arena e a E e ka 27 2 321 AICO SEACK eili aaa en a ae a a e 28 DS SS A E E T 29 253 9 GOOCAGGING cesa a a A a A N AG 30 2 3 10 Metadata CditOF isinde ednina E RAAE 32 2S li TAG GING arianna a aa a a a a sees 32 2 312 EXPO Selected niee eE 33 BD ORK OO Mbosi a a a A 37 STOVEN EW erin a a TS 38 3 2 DIr Kr
152. ick on a parameter label to reset its value to default 3 2 2 2 Comboboxes Clicking on a combobox will open a list of available options Click on the item you want to select Sometimes the selection list opens close to the bottom or top of the screen and only part of the items are visible scroll with your mouse wheel to bring up the Full list 3 2 2 3 Curves Some modules are controlled by adjusting curves More detail is given later in this chapter when the respective modules are explained 3 2 3 Module presets Presets are stored configurations for a module s parameters Some modules already have internal pre defined presets but you can also define your own Both internal and user defined presets are displayed by clicking the B icon with the currently activated preset shown in bold text The preset system also supports automatic preset selection based on image data such as Focal length ISO camera model and other fields 3 2 3 1 Creating a new preset First configure the module s parameters then click the H icon and select store new pre set The Following dialog will be shown for configuring the preset edit new preset for module lens correction k The first two fields are used to name and describe the preset In the example above we have also checked the auto apply option This brings up addi tional selection fields where you can define a filter used to decide if the preset should be 41 automatical
153. ics driver it is used as a dynamic library called libOpenCL so This library must be in a Folder where it is Found by your system s dynamic linker 219 When darktable starts it will First try to Find and load libOpenCL so and on success check if the available graphics card comes with OpenCL support A sufficient amount of graphics memory 1GB needs to be available to take advantage of the GPU If that is OK darktable tries to setup its OpenCL environment a processing context needs to be initialized a calculation pipeline to be started OpenCL source code files extension is cl need to be read and compiled and the included routines called OpenCL kernels need to be prepared for darktablele s modules If all that is done the preparation is Finished Per default OpenCL support is activated in darktable if all the above steps were successful IF you want to de activate it you can do so in core options Section 7 2 Core options by unchecking activate opencl support This configuration parameter also tells you if OpenCL initialization Failed it is greyed out in that case You can at any time switch OpenCL support off and on this will happen immediately De pending on the type of modules you are using you will notice the effect as a general speed up during interactive work and during export Most modules in darktable can take advantage of OpenCL but not all modules are demanding enough to make a noticeable
154. ifacts under certain conditions you should consider to activate the dithering module see Section 3 4 4 11 Dithering scale Set the radius of the vignetting area fall off strength Sets the progressiveness of the fall off Higher values will cause a steeper transition brightness Sets the intensity of brightening positive values or darkening negative values 105 saturation Controls how strong colors become when desaturated or saturated in the darkened or brightened vignetting area horizontal center Shifts the center of the vignetting area horizontally vertical center Shifts the center of the vignetting area vertically shape Influences the shape of the vignetting area The default value of 1 causes a circular or elliptical area Smaller values will shift the shape into a more square one higher values turn it into a cross like shape automatic ratio Click this button to automatically adjust the width height ratio of the vignetting area to the aspect ratio of the underlying image The vignetting area will typically become ellip tical width height ratio Manually adjust the width height ratio of the vignetting area dithering With this combobox you can activate random noise dithering to overcome banding arti Facts caused by vignette gradients Select 8 bit output to prevent banding on monitor display and for JPEGs When set to 16 bit output only a little dithering will be applied just strong e
155. iguration api_version_suffix string 178 The version suffix of the lua API darktable configuration api_version_string suring The version description of the lua API This is a string compatible with the semantic ver sionning convention darktable configuration check_version Funct or module_name string Bele uas Check that a module is compatible with the running version of darktable Add the Following line at the top of your module darktable configuration check M m p M2 m2 p2 To document that your module has been tested with API version M m p and M2 m2 p2 This will raise an error if the user is running a released version of DT and a warning if he is running a developement version the here will automatically expand to your module name if used at the top of your script module_name string The name of the module to report on error table Tables of API versions that are known to work with the scrip 8 2 1 11 darktable preferences table Lua allows you do manipulate preferences Lua has its own namespace for preferences and you can t access nor write normal darktable preferences Preference handling functions take a _script_ parameter This is a string used to avoid name collision in preferences i e namespace Set it to something unique usually the name of the script handling the preference Preference handling functions can t guess the type of a parameter You must pass the type of the prefere
156. iled for some reason There is a structure of Files in etc OpenCL on your system that libOpenCL so consults to find these libraries Check if you Find something fishy in there and try to Fix it Often the needed libraries cannot be found by your system s dynamic loader Giving Full path names might help e darktable might also tell you that a context could not be created This often indicates a version mismatch between loaded graphics driver and libOpenCL Check if you have left over kernel modules or graphics libraries of an older install and take appropriate action In doubt make a clean reinstall of your graphics driver Sometimes immediate ly after a driver update the loaded kernel driver does not match the newly installed libraries reboot your system in that case e darktable might crash in very rare cases directly during startup This can happen if your OpenCL setup is completely broken or if driver library contains a severe bug IF you can t Fix it you can still use darktable with option disable opencl which will skip the entire OpenClL initialization step e darktable might Fail to compile its OpenCL source files at run time In that case you will get a number of error messages looking like typical compiler errors This could indicate an incompatibility between your OpenCL implementation and our interpretation of the standard In that case visit us at darktable devel sourceforge net and report the prob lem Chances are goo
157. ilm if the directory is already imported darktable films delete see types dt_lua_film_t delete 8 2 1 6 darktable new_Format Fume eon type string types dt_imageio_module_format_t Creates a new format object to export images type Sir iG The type of Format object to create one of e copy e exr e j2k e jpeg e pfm png ppm e tiff e webp return types dt_imageio_module_format_t 165 The newly created object Exact type depends on the type passed 8 2 1 7 darktable new_storage LUMO Lon type string types dt_imageio_module_storage_t Creates a new storage object to export images type String The type of storage object to create one of e disk e email e Facebook e Flickr e gallery e latex e picasa Other lua defined storage types may appear return types dt_imageio_module_storage_t The newly created object Exact type depends on the type passed 8 2 1 8 darktable gui This subtable contains Function and data to manipulate the darktable user interface with Lua Most of these Function won t do anything if the GUI is not enabled i e you are using the command line version darktabl cli instead of darktable darktable gui action_images table A table of types dt_lua_image_t on which the user expects UI actions to happen It is based on both the hovered image and the selection and is consistent with the way darktable works It is recommended to use this table to implement Lua actions rather th
158. image_t red types dt_lua_image_t yellow 192 see types dt_lua_image_t red types dt_lua_image_t purple see types dt_lua_image_t red types dt_lua_image_t reset SeLLSruner ont Removes all processing From the image reseting it back to its original state self types dt_lua_image_t The image whose history will be deleted types dt_lua_image_t delete self ftu unction Removes an image from the database self types dt_lua_image_t The image to remove types dt_lua_image_t group_with self CUunctron image types dt_lua_image_t Puts the first image in the same group as the second image If no second image is provided the image will be in its own group self types dt_lua_image_t The image whose group must be changed image types dt_lua_image_t The image we want to group with types dt_lua_image_t make_group_leader self function Makes the image the leader of its group 193 self types dt_lua_image_t The image we want as the leader types dt_lua_image_t get_group_members self function table of types dt_lua_image_t Returns a table containing all types dt_lua_ image tof the group The group leader is both at a numeric key and at the leader special key so you probably want to use ipairs to iterate through that table self types dt_lua_image_t The image whose group we are querying return table of types dt_lua_image_t A table of image objects containing all images that are in the
159. ind of collection is a Film roll cov ering all the images which have been imported from a specific Folder on disk You can easily construct other kinds of collections based on various image attributes like EXIF data Filename tags etc Multiple criteria can be logically combined to narrow or ex tend your collection see Section 2 3 2 Collect images darktable keeps a list of the most recently used collections for quick access see Sec tion 2 3 3 Recently used collections 2 2 3 Thumbnails Each image of the current collection is represented by a thumbnail in the lighttable view darktable keeps a cache of thumbnails on disk a so called mipmap cache the size of which can be adjusted in the core preferences dialog see Section 7 2 Core options 2 2 3 1 Thumbnail creation 16 Thumbnails get created whenever darktable imports an image for the First time after an image has been modified in the darkroom or when revisiting an old image whose thumb nail has already been dropped from the cache When darktable imports an image for the first time there are two possible sources from where to take a thumbnail darktable can either try to extract an embedded thumbnail out of the input image most RAW files contain these kind of thumbnails generated by the camera or process the image by itself using default settings You can define how darktable gets its thumbnails in the gui preferences dialog see Secti
160. ing thus allowing other Lua callbacks to run 8 2 4 4 attributes parent This object inherits some methods From another object You can call the methods from the parent on the child object 8 2 5 system This section documents changes to system Functions 8 2 5 1 system coroutine system coroutine yield fu unctr on 213 type types yield_type extra variable variable Lua Functions can yield at any point The parameters and return types depend on why we want to yield A callback that is yielding allows other Lua code to run e wait_ms one extra parameter the execution will pause for that many miliseconds yield returns nothing e file readable an opened file from a call to the OS library will return when the file is readable returns nothing e run_command a command to be run by sh c will return when the command termi nates returns the return code of the execution type types yield_type The type of yield extra variable An extra parameter integer for wait_ms open file For File readable string For run_command return variable Nothing for wait_ms and file_readable the returned code of the command for run_command 214 Chapter 9 Special topics This chapter touches several technical topics which might help you to get darktable run hing on specific hardware or optimize its performance A lot of additional technical back ground information and many tips and tricks are als
161. ing steps and parameters that you want to be applied specifi cally to exported images e g you may define a style that adds a stronger level of sharp ening when you produce scaled down JPEG files for the internet Learn more about styles in Section 2 3 8 Styles and Section 3 3 3 History stack Pressing this button starts a background job to export all selected images A bar at the bottom of the left side panel displays the progress Whenever a file is successfully export ed a notification message pops up for a Few seconds You may click on the pop up to make it disappear 35 36 Chapter 3 Darkroom The darkroom view is where you develop your image A A r Be g _ y Ak _ i 3 1 Overview 38 Darkroom mode is for photographic development of the image that you selected from the lighttable Numerous tools named modules are available for processing that image On the left hand side you have navigation snapshot history stack color picker image information and mask manager panels described in Section 3 3 Darkroom panels In the right hand panel you can see the histogram and a list of modules available for working with the image At the bottom of the right hand panel you can enable disable the view of individual modules You can use middle click to zoom 1 1 A double middle click takes you to 2 1 Alternatively you can zoom in and out between 1 1 and Fit to screen by mouse scrollin
162. ipe In order to avoid banding you may activate this module As dithering con sumes significant resources this module is disabled by default 97 Usage Although banding is not an inherent problem of any of darktable s modules some op erations may provoke it as they produce a lightness gradient in the image To mitigate possible artifacts you should consider to activate dithering when using the vignette and the graduated density module respectively see Section 3 4 5 4 Vignetting and Sec tion 3 4 5 13 Graduated Density This is especially relevant for images with extended homogeneous areas like cloudless sky Also when using a gradient mask see the section called gradient you should watch out for possible banding artifacts IF you export images with a reduced width height and want best dithering results please make sure that you de activate option do high quality resampling during export in core options see Section 7 2 Core options else the final scaling step will counteract dither ing Viewing from some distance an image dithered into a very low bit depth like Floyd steinberg 1 bit b amp w will give the impression of a homogeneous grayscale image We try to mimic this impression in darktable when you look at zoomed out images in the cen ter view in the navigation window and for thumbnails This is accomplished by dithering those images into a higher number of grayscale levels Note that as
163. is panel allows for a quick selection of images ac cording to some common criteria 2 3 5 1 Usage select all recently used collections film roll Bilder September 2012 film roll Bilder Testbilder film roll Oktober 2012 Rohbilder image information filmroll Bilder Testbilder image id 11519 filename IMG_4158_0019 jpg version 0 ihome pegelow B _4158_0019 jpg no Canon EOS 5D Mark Il Canon Canon EF 50mm fM 2L FM1 0 1 50 50 mm stance SO 400 datetime 2012 06 18 15 34 00 width 3620 5434 longitude Select all images in the current view collection with respect to the filters select none De select all images invert selection Select all images that are not currently selected 26 select Film roll Select all images that are in the same film roll as the currently selected images select untouched Select all images that have not yet been developed 2 3 6 Selected image s This panel provides some actions that operate on se selected images Y lected images emove delete copy duplicate reset rotation cache locally reset cache group ungroup 2 3 6 1 Usage remove delete move copy Remove the selected images From the darktable database Those images will not be shown in lighttable anymore but remain on the filesystem As darktable stores XMP files with your development parameters on disk you can later Fully reconstruct your work by just re importing the images
164. it your needs by selecting the exclusive amp inverted or inclusive amp inverted options 53 3 2 9 2 Usage You will typically want to combine drawn and para blend drawn amp parametric mask 7 metric masks to first select a certain region of your ERES O image either by the drawn or the parametric mask opacity 100 drawn mask o mask used Y and use the other mask type to finetune your selec D O tion Finetuning can either mean that you want to in a a eis 00 clude Further parts of the image which are not in output oO o 100 100 cluded in the First place or you want to exclude parts LS es o of the image that were previously included 4 gt combine masks exclusive Y mask blur 0 0 og This gives two typical use cases Inclusive mode For this mode you set the combine masks combobox to inclusive and make sure that all polarity buttons of all the individual channels and of the drawn mask are set to negative E Your starting point is a mask where all pixels have a value of zero i e no pixel is selected You now adjust the parametric mask sliders to bring more and more pixels into the selection or you draw shapes on the canvas to select specific areas of your image Exclusive mode In the opposite case you set the combine masks combobox to exclusive and make sure that all polarity buttons are set to positive Your starting point is a mask with all values at 1 0 i e all pixels selec
165. ix to apply darktable offers many widespread matrices along with an enhanced matrix for some camera models The enhanced matrices were processed by the darktable team in order to provide a look closer to the manufacturer s You can also supply your own input ICC profiles and put them into SDARKTABLE share darktable color in or SHOME config darktable color in SDARKTABLE is used here to represent darktable s installation directory and HOME your home directory One com mon source of ICC profiles is the software that is shipped with your camera it often con tains profiles specific to your camera model You may need to activate module unbreak input profile see Section 3 4 3 11 Unbreak input profile to use your extra profiles IF your input image is a low dynamic range File like JPEG or a raw in DNG Format it might already contain an embedded ICC profile which darktable will use as a default You can always overrule darktable and select a different profile Select embedded icc profile to restore the default gamut clipping 88 This combobox lets you activate a color clipping mechanism In most cases you can leave it at its default off state However if your image shows some specific Features like highly saturated blue light sources gamut clipping might be useful to avoid black pixel artifacts See Section 3 2 10 3 Possible color artifacts for more background information You can select from a list of RGB profiles
166. k 7 grp levels gradient 1 remove from group gradient path 3 circle 4 node union brush 5 node intersection ellipse 46 circle 7 cleanup unused shapes Masks are constructed by adding the shapes in the order that they are listed from top to bottom Each shape adds to the mask by using at your choice one out of four logical set operators As order matters when combining shapes you may move each shape up or down if needed Each shape before being added can be inverted and is then depicted by the symbol 3 3 5 5 Set operators union 60 We use as an example a combination of a gradient Followed by a path to demonstrate the effect of the set operator which we apply to the path shape As a convention we say that a pixelis selected in a mask or shape if it has a value higher than zero This is the default set operator It is depicted by the wi symbol left to the shape name The shape adds to the existing mask in such a way that the resulting mask contains the pixels that are either selected in the existing mask or in the added shape In overlap ping areas the maximum value is taken intersection This set operator is depicted by the El symbol left to the shape name The shape adds to the existing mask in such a way that the resulting mask contains only pixels that are selected in both the existing mask and the added shape In overlapping areas the minimum value is used In the given exam
167. k the range of values where opacity is 1 Two triangles below the slider mark the range values where opacity is zero Intermediate points between Full and zero opacities are given a proportional opacity The filled triangles or inside markers indicate the closed mostly narrower edge of the trapezoidal Function The open triangles or outside markers indicate the open mostly wider edge of the trapezoidal Function The sequence of the markers always remains un changed they can touch but they can not switch position A polarity button land B respectively to the right of the slider switches between range selectand range de select Function modes with visual confirmation provided by exchanging the upper and the lower triangle markers These two types of trapezoidal Functions are represented graphically in the Following images Range select Function Range de select Function Opacity Opacity 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 L value L value A trapezoidal Function that selects a A trapezoidal Function that de selects a narrow range of values for blending narrow range of values from blending 51 In their default state all markers are at their extreme positions maximum left and maxi mum right respectively In this state a range select Function selects the whole range of values giving an all at 100 mask Starting From there one can move the sliders inwards to gradually take out more an more par
168. ktable styles delete Function style types dt_style_t Deletes an existing style style types dt_style_t the style to delete darktable styles duplicate Tune LALO style types dt_style_t name string QeSCripeion 4 String types dt_style_t Create a new style based on an existing style style types dt_style_t The style to base the new style on name SELLNG The new style s name description SCEI The new style s description return types dt_style_t 183 The new style object darktable styles apply Eire e orn style types dt_style_t image types dt_lua_image_t Apply a style to an image The order of parameters can be inverted style types dt_style_t The style to use image types dt_lua_image_t The image to apply the style to darktable styles import Tune oD Lon filename string Import a style from an external dtstyle File Filename SEring The file to import darktable styles export TUCE style types dt_style_t directory string overwrite boolean Export a style to an external dtstyle file style types dt_style_t The style to export directory String The directory to export to 184 overwrite boolean Is overwriting an existing File allowed 8 2 1 13 darktable database Allows to access the database of images Note that duplicate images images with the same RAW but different XMP will appear multiple times with different duplicate indexes Also
169. lapse 126 A timelapse is a video clip composed of images taken in a time sequence A typical example is to take a timelapse of cityscapes where you capture clouds and traffic etc To setup a timelapse capture create a new session as described previously Now decide if you want to shoot in manual or auto mode Only use auto in situations were the ambient light will change significantly during the time of the shoot eg shooting a timelapse over 24 hours might give you easier control of light in that kind of captured sequence The camera settings panel is where you define delay and sequence Sequence will give you the opportunity to choose how many images you want to capture and delay will set the time in seconds between captures To start the capture click the capture button in the same panel and watch the Filmstrip Fill up with images The latest captured image is always displayed in center view 4 4 Troubleshoot 4 4 1 Verify that your camera is supported This troubleshooting guide will give you steps to verify your camera can be used with tethering This is done using the gphoto2 commandline tools This is what darktable uses to interface with your camera 1 Verify that camera is detected The Following command will verify a camera that is connected to the computer and detected by gphoto2 Find your camera port name to use it in the Following tests below Usually port usb will be enough and therefore used in these examples
170. le styles export types dt_style_t name string The name of the style types dt_style_t description string The description of the style types dt_style_t types dt_style_item_t The different items that make the style 8 2 2 22 types dt_style_item_t dt_type An element that is part of a style 203 Attributes e has_tostring types dt_style_item_t name string The name of the style item types dt_style_item_t num number The position of the style item within its style 8 2 2 23 types dt_lua_tag t dt_type A tag that can be attached to an image Attributes e has_tostring types dt_lua_tag_t delete see darktable tags delete types dt_lua_tag_t attach see darktable tags attach types dt_lua_tag_t detach see darktable tags detach types dt_lua_tag_t name string The name of the tag types dt_lua_tag_t types dt_lua_image_t The images that have that tag attached to them 8 2 2 24 types dt_lib_module_t dt_type The type of a UI lib types dt_lib_module_t id string A unit string identifying the lib types dt_lib_module_t name 204 string The translated title of the UI element types dt_lib_module_t version number The version of the internal data of this lib types dt_lib_module_t visible boolean Allow to make a lib module completely invisible to the user Note that if the module is invisible the user will have no way to restore it without lua Attributes e implicit_yield e write types dt_lib_mod
171. led data flow will add to the total processing time This is especially important for the small image buffers we need to handle during interactive work They can be processed quickly by a fast GPU However even short term stalls of the pixelpipe will easily become a bottleneck On the other hand darktable s performance during File exports is more or less only gov erned by the speed of our algorithms and the horse power of your GPU Short term stalls will not have a noticeable effect on the total time of an export darktable comes with default settings that should deliver a decent GPU performance on most systems However if you want to fiddle around a bit by yourself and try to optimize things Further here is a description of the relevant configuration parameters opencl_async_pixelpipe This boolean flag controls how often we block the OpenCL pixelpipe and get a status on success failure of all the kernels that have been run For optimum latency set this to TRUE so darktable runs the pixelpipe asynchronously and tries to use as Few inter rupts as possible IF you experience OpenCL errors like Failing kernels set the parame ter to FALSE darktable will then interrupt after each module so you can more easily isolate the problem Problems have been reported with some older ATI AMD cards like HD57xx which can produce garbled output if this parameter is set to TRUE IF in doubt leave it at its default FALSE opencl_number_event_handles Event
172. lend modes have a look at Section 3 2 6 Blending operators patch size This slider is only available if mode non local means is selected It controls the size of the patches being matched when deciding which pixels to average see also Section 3 4 4 4 Denoise Non local means Setting this to higher values can give more sharpness Pro cessing time will stay about the same strength 92 This parameter is here to fine tune the strength of the denoise effect The default value has been chosen to maximize the peak signal to noise ratio It s mostly a matter of taste if you prefer a rather low noise level at the costs of a higher loss of detail or if you accept more remaining noise in order to have finer structures better preserved within your image 3 4 4 4 Denoise Non local means Overview This is a denoise algorithm which will work on chro 2008 denoise non local means Y ma and or luma patch size 3 strength luma chroma blend Usage This module reduces noise in your image but preserves structures This is accomplished by averaging each pixel with some surrounding pixels in the image The weight of such a pixel in the averaging process depends on the similarity of its neighborhood with the neighbor hood of the one pixel to be denoised A patch with a certain size is used to measure that similarity As denoising is a resource hungry process it slows down pixelpipe processing significantly
173. lor correction module Use it to give an image an over all tint or to adjust overall color saturation The color zones module offers a much Finer control to adjust saturation or lightness and even hue in user defined zones darktable s tone curve module in addition to the classical adjustment of tonal values gives you Fine control over the colors in an image Finally if you intend to convert an image into black amp white a good starting point with an easy to use and intuitive user interface is offered by the monochrome module Alternatively you might consider using darktable s channel mixer 1 3 2 11 Sharpening IF you start your workflow from a RAW image you will need to have your final out put sharpened The sharpen module can do this with the classical USM unsharp mask approach available in most image processing software Another very versatile way to enhance edges in an image is offered by the highpass module in combination with darktable s rich set of blending operators 1 3 2 12 Artistic effects darktable comes with a rich set of artistic effect modules To name just a Few with the watermark module you add an individual watermark to your image The grain module sim ulates the typical noise of classical analogue Footage Use the color mapping module to transfer the look and feel of one color image onto another darktable s low light module allows to simulate human vision to make lowlight pictures look closer to reality
174. ls 96 rotating an image 65 S saturation 71 see also color contrast see also color zones see also tone curve save button 8 19 scale pixels 95 scripting 151 selected images 27 selecting images 26 shadows and highlights 67 shapes see mask shapes sharpen 90 sidecar files 19 29 skulls 17 sliders 40 slideshow view 133 snapshots 57 soften 106 sort order 18 splittoning 104 spot removal 96 star ratings 17 stitched panoramas 218 styles 30 T tags 32 tethering view 123 camera settings 125 live view 125 sessions 125 thumbnails 16 tiling 217 tone curve 76 tonemapping 79 233 see also global tonemap U unbounded colors 55 unbreak input profile 89 underexposed warning 63 V velvia 81 vibrance 88 vignetting 105 W watermark 101 white balance 73 X XMP files 19 29 Z zone system 78 zoom 38 57 234
175. ly For a given source image multiple editing versions called duplicates can co exist sharing the same input RAW data but each having their own metadata tags and history stack Each duplicate is represented by a separate XMP sidecar File with a Filename construct 19 ed in the form lt basename gt _nn lt extension gt xmp where nn represents the minimum two digit version number of that edit Information for the initial edit the duplicate with version number zero is stored in the sidecar file lt basename gt lt extension gt xmp The version number of a duplicate is displayed in the image information panel in each of darktable s views see an example in Section 2 3 4 Image information Sidecar Files automatically synchronize with your work without the need to press a save button When backing up your data make sure you also keep the XMP files as these are needed to Fully reconstruct your work in case of a disaster In addition to the sidecar files darktable keeps all image related data in its database for Fast access An image can only be viewed and edited from within darktable if its data is loaded in that database This automatically happens when you first import an image or at any later time by re importing it see Section 2 3 1 Import In the latter case the database gets updated with data that darktable finds in the sidecar files belonging to that image Once an image has been impo
176. ly applied when opening other similar images in darkroom for the first time The example dialog above sets up Following rules if lens name matches and aperture is greater or equal to F 8 and Focal length is between 24 and 35mm the preset will be auto matically applied Also the second checkbox is clicked so this preset will only be shown in the preset list if the image matches the rule darktable finds this data in your image s EXIF information IF you want a preset to be ap plied to all images from a specific camera leave all Fields at default values except For the model field Tip The image information panel for your image displays your model name use this to ensure you have the correct spelling see Section 2 3 4 Image information 3 2 3 2 Managing Presets Both user created and pre defined presets can be viewed and managed from within the presets menu Section 7 5 Presets in the preferences dialog see Chapter 7 Preferences and settings 3 2 4 Multiple instances Many of darktable s modules can be applied multiple times Each instance of that module behaves like any other module taking its input from the module below in the pixelpipe delivering its output to the module above 3 2 4 1 Typical use cases 42 There are many occasions where it makes sense to have an operation act more than once in the pixelpipe Here are a few use cases e Most of our modules are highly versatile and depending on parameters can
177. m 0 to 8 preset Select a preset white balance camera white balance default White balance reported by the camera spot white balance Select a square area in your image containing mostly grey pixels The white balance is calculated based on the selected area passthrough Show without adjusting For white balance camera presets Camera specific white balance presets Examples di rect sunlight Flash cloudy shade and a number of in door lighting options Finetune Some cameras offer additional Finetuning parameters if one of the camera presets is se lected Depending on camera white balance can be adjusted in steps within a certain range The adjustments are usually towards yellow value lt 1 or blue value gt 1 3 4 1 10 Invert Overview The main purpose of this module is to invert scanned 0 0 invert ne g d tive S color of film material E 7 Usage color of film material The only control element of this module is a color selector which allows to adjust For dif Ferent colors of your Film material Clicking on the colored Field will open a color selector dialog which allows to define a color in HSL or RGB color space You can also activate a color picker by pressing il and take a color probe From your image preferably from the unexposed border of your negative 3 4 2 Tone group This group contains modules that operate on the tonal values of an image modulating brightness while leaving color v
178. mage 210 preferences 179 preset 199 print 160 print_error 160 publisher 189 purple 193 quality 197 198 198 rating 192 ratings 172 ratio 170 read 181 recentcollect 172 recommended _ height 199 recommended_width 199 red 192 register 179 register_event 160 register_storage 161 reset 193 205 rights 190 select 173 206 selected 170 selection 167 session 174 shortcut 211 show_ overlays 172 slideshow 169 snapshots 169 Snapshot_direction_t 207 styles 170 182 supports format 200 system 213 tagging 171 tags 175 take snapshot 170 tethering 169 title 189 201 201 tmp_dir 178 type 188 types 188 valid 206 verbose 178 version 178 205 view changed 212 views 168 viewswitcher 171 view_toolbox 175 visible 205 width 192 199 write 181 213 232 write_image 195 yellow 192 yield 213 yield_type 208 zoom 168 M map view 129 Find location 131 map settings 131 mask manager 59 mask shapes 48 brush 48 circle 48 ellipse 48 gradient 49 path 49 masks 47 combined masks 53 drawn masks 47 parametric masks 50 memory setup 216 32 bit systems 217 64 bit systems 218 metadata editor 32 module groups 61 module presets 41 module processing order 39 module usage 39 comboboxes 41 Sliders 40 modules 65 base curve 69 bloom 111 channel mixer 81 chromatic aberration 99 color balance 86 color contrast 84 color correction
179. make the output image span the full available tonal range A previously flat looking image will get more contrast and pop Moving the middle bar will modify the middle gray tones Shifting it left will make the im age look brighter shifting it right will make it darker This is often referred to as a change of image gamma There are three color pickers in black gray and white available by pressing the respec tively colored i icon You can use them to sample the corresponding level directly From the image 15 mode black gray white The auto button autoadjusts the black and white point and puts the gray point exactly in the mean between them In automatic mode the module automatically analyses the histogram of the image de tects the left and right histogram borders and lets you define the black point the gray point and the white point in terms of percentiles http en wikipedia org wiki Percentile relative to these borders Tip Under certain conditions especially highly saturated blue light sources in the frame the levels module may produce black pixel artifacts See the gamut clipping option Sec tion 3 4 3 10 Input color profile on how to mitigate this issue Set the mode of operation of this module Defaults to manual Sets the black point in percentiles relative to the left border of the histogram only au tomatic mode Sets the gray point in percentiles relative to the l
180. mat type to check return boolean True if the format is supported by the storage 8 2 2 13 types dt_imageio_module_storage_data_email dt_type An object containing parameters to export to email Attributes e parent types dt_imageio module storage t 8 2 2 14 types dt_imageio_module_storage_data_Flickr dt_type An object containing parameters to export to Flickr Attributes e parent types dt_imageio module storage t 8 2 2 15 types dt_imageio_module_storage_data_facebook dt_type An object containing parameters to export to Facebook Attributes e parent types dt_imageio_ module storage t 8 2 2 16 types dt_imageio_module_storage_data_latex 200 dt_type An object containing parameters to export to latex Attributes e parent types dt_imageio_ module storage t types dt_imageio_module_storage_data_latex filename String The Filename to export to Attributes e write types dt_imageio_module_storage_data_latex title string The title to use for export Attributes e write 8 2 2 17 types dt_imageio_module_storage_data_picasa dt_type An object containing parameters to export to picasa Attributes e parent types dt_imageio_module storage t 8 2 2 18 types dt_imageio_module_storage_data_gallery dt_type An object containing parameters to export to gallery Attributes e parent types dt_imageio_ module storage t types dt_imageio_module_storage_data_gallery filename string The Filename to export to Attributes e write types dt_imageio
181. mb nails surrounded by a Frame When the mouse is over an image its rating and color labels are shown in the Frame along with an indicator of whether the im age has already been altered in darkroom Also when the mouse hovers over an image frame image infor mation EXIF data metadata is shown in the image information panel at the bottom left While the mouse is over an image Frame there are a number of actions you can perform Here is a table of keyboard shortcuts and assigned actions 0 5 set the rating of the image if an image has 1 star and you hit the 1 key the image will be unrated Pressing rrejects the image F1 F5 set a color label ctrl c copy the history stack ctrl v paste the copied history stack d open in darkroom view for developing Z fully zoom into the image while the key is pressed ctrl z fully zoom into the image and show areas in focus The overlay button taf located in the upper panel activates the permanent display of star ratings and image changed indicator on all thumbnails By default these overlays are only visible on the thumbnail under the mouse cursor An overlay button is also available in the other views where it affects the filmstrip accordingly see Section 1 2 3 Filmstrip and Section 3 3 9 4 Filmstrip In the bottom panel you have an option to choose between zoomable lighttable view or Filemanager view of the thumbnails In zoomable lighttable view scroll with your mo
182. more in performance and will render OpenCL useless for you especially when exporting files Another environment variable which changes driver behavior iS GPU_MAX_ALLOC_PERCENT You could set this to 100 in order to allow memory alloca tions as high as 1GB on your AMD ATI card The problem is this tends to cause darktable to crash sooner or later Our recommendation is to leave these settings untouched Often your card will be recog nized with 512MB memory and a maximum allocation size of 128MB There are three con figuration parameter which you set in File SHOME config darktable darktablerc to get things running Here are the details opencl_memory_requirement Set this parameter to 500 so that darktable will accept your 512MB graphics memory as being sufficient in memory opencl_memory_headroom This parameter controls how much graphics memory out of the reported one dark table should leave untouched for driver and display use As for AMD ATI devices we anyhow only can get half of the available RAM it s safe to set this to zero So all of the 512MB can be used by darktable opencl_avoid_atomics Atomic operations in OpenCL are a special way of data synchronization They are only used in a few kernels Unfortunately some most AMD ATI devices are extremely slow in processing atomics It s better to process the affected modules on CPU rather than accepting an ultra slow GPU codepath Set this parameter to TRUE if you experi ence slow
183. multiple parameters for controlling how reer the color picker works whose settings remain in ef restrict histogram to selection Fect until you leave the darkroom mode display sample areas on image Besides the global color picker described here there are also local color pickers in some of the modules eg tone curve Global and local color pickers are different The global color picker works in monitor color space and takes samples after the complete pixelpipe has been processed The local color pickers run in the color space of the individual module which is usually Lab they reflect the input and output data of that specific module within pixelpipe The global color picker can be run in point or area mode When in point mode only a small spot under your cursor is taken as a sample In area mode you can draw a rectangle and darktable samples the area within that rectangle The combobox to switch between point and area mode can also be used to toggle the mode of local color pickers IF samples are taken in area mode darktable will calculate mean min and max color chan nel values A combobox allows you to select which of those are displayed For obvious statistical reasons mean min and max are identical For the single sample of point mode A color swatch representing the sampled point or area is displayed Numerical values are shown as well As said before global color picker works in monitor RGB color space You can also let darktable
184. must be specified here 8 2 1 4 darktable register_storage FUnCELOn plugin name string name string e care 2 FUNCE Lon Mra we amp FOner Or l Supported LunceLon ate LlalrZe es FUNCtLon This Function will add a new storage implemented in Lua A storage is a module that is responsible for handling images once they have been gener ated during export Examples of core storages include Filesystem e mail Facebook plugin_name String A Unique name for the plugin name string A human readable name for the plugin store FUnNCE LOM storage types dt_imageio_module_storage_t image types dt_lua_image_t format types dt_imageio_module_format_t filename string number integer total integer high_quality boolean extra_data table This Function is called once for each exported image Images can be exported in par allel but the calls to this Function will be serialized 161 storage types dt_imageio_module_storage_t The storage object used for the export image types dt_lua_image_t The exported image object Format types dt_imageio_module_format_t The format object used for the export Filename SELLING The name of a temporary file where the processed image is stored number integer The number of the image out of the export series total integer The total number of images in the export series high_quality boolean True if the export is high q
185. n Let s look at the code in details We first define a Function with two parameters These pa rameters are strings this is documented in the section called events shortcut callback The first one is the type of event that is triggered shortcut and the second one is what shortcut specifically A shortcut that print its parameters The Function itself calls darktable print that will print the message as an overlay in the main window Once that function is defined we register it as a shortcut callback To do that we call darktable register_event whichis a generic Function for all types of events We tell it that we are registering a shortcut event then we give the callback to call and last we give the string to use to describe the shortcut in the preference window Let s try a shortcut a little more interactive This one will look at the images the user is currently interested in selected our moused over and will increase their rating darktable require darktable darktable register_event Shortcut function event shortcut local images darktable gui action_images for _ v in pairs images do Veracini ECIN l end end Increase the rating of an image At this point most of this code should be self explanatory Just a couple of notes e instead of declaring a function and referencing it we declare it directly in the call to darktable register_event this is strictly equivalent but slightly more compac
186. n the current status of the image overlays option Attributes e write darktable gui libs filter The image filter menus at the top of the UI Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs import The buttons to start importing images Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs ratings The starts to set the rating of an image 172 Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs select The buttons that allow to quickly change the selection Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs collect The collection UI element that allows to Filter images by collection Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs colorlabels The color buttons that allow to set labels on an image Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs lighttable_mode The navigation and zoom level UI in lighttable Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs copy_history The Ul element that manipulates history Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs image The Ul element that manipulates the current image Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs modulegroups The icons describing the different iop groups Attributes e has_tostring 173 e parent t
187. n 3 4 3 6 Mono chrome You can then simulate a color filter by dragging the circle above the colours you want to filter Filter size can be modified thanks to wheel scrolling 3 5 1 3 The simple way color correction module To perform such conversion we use the color correction module Section 3 4 3 5 Color correction 1 Activate the color correction module 2 Use the bottom slider to set saturation to zero 3 5 1 4 The artistic way color zones module To perform the conversion we use the color zone module Section 3 4 3 7 Color zones 1 Activate the colour zones module 2 By default the active tabbed control is set to saturation whereas the select by com bobox is set to hue This means that color are selected according to their hue hori zontal scale and you can change for each hue its saturation vertical scale You sim ply need to set all points to the minimum of the vertical scale to de saturate every hue 3 But now if you want you can keep some hues a little bit saturated so your image will be all black and white but some hue A classical use for portrait is to keep red hue saturated in order to make the lips standing out You can also use one of the available presets that perform black and white conversion keeping some hues saturated 3 5 1 5 The sophisticated way channel mixer module To perform the conversion we use the channel mixer module Section 3 4 3 2 Channel
188. nce you are handling Note that the directory enum and file type preferences are stored internally as string The user can only select valid values but a lua script can set it to any string darktable preferences register 179 180 EUMCE aon grip 2 OCELO name string type types lua_pref_type Tapel lt Skring COOLED z Str LNO default depends on type Maan ate Or Eloa manr g nE Or oer step float values string Creates a new preference entry in the Lua tab of the preference screen IF this Function is not called the preference can t be set by the user you can still read and write invisible preferences script SEELIG Invisible prefix to guarantee unicity of preferences name String A unique name used with the script part to identify the preference type types lua_pref_type The type of the preference one of the string values described above label String The label displayed in the preference screen tooltip String The tooltip to display in the preference menue default depends on type Default value to use when not set explicitely or by the user For the enum type of pref this is mandatory min int or float Minimum value integer and Float preferences only max Inc Or i Loatk Maximum value integer and float preferences only step float Step of the spinner float preferences only values Sie Pees as Other allowed values enum preferences only
189. nces and control existing ones see Section 3 2 4 Multiple instances The most frequently used control elements of modules are sliders comboboxes and curves 3 2 2 1 Sliders 40 Sliders offer Four different ways of interaction depending on the level of control you need 1 Triangular marker Left click the slider s triangular marker and drag it to the left or right 2 Mouse wheel Hover over any place on the slider with your mouse then use your mouse wheel to adjust the value step by step 3 Right click When your mouse is over a slider right click gives you a multi functional pop up below the slider For Fine control with your mouse or numerical entry using the keyboard darktable s innovative input method for both coarse and fine value adjustments in a single con trol element combined with keyboard input A bent line extending from the triangular marker moves as you move your mouse The closer your mouse pointer is to the triangular marker the coarser the control the Further away from the triangular marker the finer is your control Left click with your mouse to accept the new value and go back to normal control Alternatively you can type in a new value using your keyboard and commit by hitting the enter key You may even supply the new value in the Form of an arithmetic expressions aon which darktable will calculate for you the old value is referenced as x 4 Double click You can double cl
190. nfiguration option see Section 7 1 GUI options controls how much smoothing is applied A higher level of smoothing leads to less nodes this eases subsequent editing at the expense of a lower initial accuracy Nodes and segments of a brush stroke can be modified individually See the documenta tion on path below for more details Rendering a complex brush shape can consume a significant number of CPU cycles con sider to revert to the circle ellipse or path shape if possible A brush stroke with controls and activated mask dis play Clicking the Bi symbol adds a circle shape Click into the canvas to place the circle Left click and drag the circle to a different position if needed Use the scroll wheel of your mouse while in the circle to change the diameter scroll within the circle border to adjust the width of the gradual decay With ctrl scroll you can adjust the opacity of the circle this is best observed with the mask displayed by pressing the El button A circle shape with controls and activated mask dis play Clicking the Ei symbol adds an ellipse shape path gradient The general principle is the same as For the circle shape In addition you get four nodes on the ellipse line Click on the nodes to adjust the ellipse s eccentricity ctrl click on them to rotate the ellipse An ellipse shape with controls and activated mask display Clicking the Zi symbol adds a shape defined by a user d
191. ng the Filename structure for each imported image Several pre defined variables can be used in the pattern as placeholders S HOME PICTURES_ FOLDER DESKTOP USERNAME FILE_NAME S JOBCODE SEQUENCE ID EXIF_SECOND EXIF_ISO base directory naming pattern FILE_EXTENSION the home folder as defined by the system the pictures Folder as defined by the system usually SHOME Pictures the desktop folder as defined by the system usally SHOME Desktop your user account name on the system basename of the imported image extension of the imported image unique identifier of the import job a sequence number within the import job unique identification number of the image in darktable s database year at the date of import month at the date of import day at the date of import hour at the time of import minute at the time of import second at the time of import year the photo was taken from EXIF data month the photo was taken from EXIF data day the photo was taken from EXIF data hour the photo was taken from EXIF data minute the photo was taken from EXIF da ta seconds the photo was taken From EXIF da ta ISO value of the photo from EXIF data The base directory part of the naming pattern default PICTURES FOLDER Dark table sub directory naming pattern The sub directory part of the naming pattern default S YEAR S MONTH S DAY _S J
192. nks making logical Film rolls Checking ignore jpeg Files is a good choice if there are JPEG images in the same Folder that you do not want to process eg if the camera stores RAW JPEG you often only want to work on the RAWS leaving the JPEG images alone You can also apply some metadata during import see Section 2 3 10 Metadata editor For more details Importing a Folder does not mean that darktable copies your images into another Folder It just means that the images are visible in lighttable and thus can be developed IF you delete an image or a Folder From disk after having imported them darktable cannot access them anymore Importing an image or Folder in darktable is not a backup of your Filesys tem Moreover darktable does not watch for changes in the Filesystem Thus if you add an image to a folder after having imported that folder in darktable the new image will not be shown until explicitly imported 2 3 1 2 Importing from a connected camera When a camera is detected it will show up in the de Y import vice panel after pressing scan for devices IF you age hover your mouse over the camera tab label a tooltip folder will pop up with information about the camera such See SAP as model Firmware version and more Depending on the camera s support buttons with actions will be Uae available such as import from camera and teth i ered shoot acini Import from camera This will bring u
193. noising clarity and lo cal contrast enhancement It works in the wavelet do main and parameters can be tuned For each frequen cy band separately Usage Each frequence band can be tweaked independently In particular you can adjust contrast boost and denoise threshold splines for both lightness and chromaticity as well as the acuteness edge of the wavelet basis on each Frequency scale Each spline can be dragged with a proportional ed it approach use the mouse wheel to adjust the ra dius in which your changes will have an effect The transparent area indicates where you would drag the spline with the current mouse position and radius The small little triangles on the x axis can be moved to alter the x position of the spline nodes Drag the upper line bright circles here For the light hess channel to affect local contrast Pulling it up as shown here will result in a contrast boost for that Frequency band Higher Frequencies i e smaller de tails are to the right of the grid Pulling it down works too The bottom spline black circles is used to perform denoising It adjusts the wavelet shrinkage threshold For each Frequency band Pull it up to see the effect In this example the noise which has been amplified by local contrast enhancement is removed This screen shows the effect of the edge parameter It is here pulled down to zero For all bands This is ef Fectively a regular a trous wavelet without e
194. nough to compensate for banding on the fine grained 16 bit level This fea ture is mostly obsoleted by our new module dithering see Section 3 4 4 11 Dithering Examples An image with vignetting and with graphical vi gnetting controls displayed 3 4 5 5 Soften Overview This module is an artistic Feature that creates a soft EEI ened image commonly known as the Orton effect size saturation brightness mix blend 106 Usage Michael Orton achieved his results on slide Film by using two exposures of the same scene one well exposed and one overexposed he then used a darkroom technique to blend those into a final image where the overexposed image was blurred This module is almost a copy of Orton s analogue process into the digital domain You can control brightness and blur with the provided parameters we also add a control for saturation of the overexposured image for more play size Set the size of blur of the overexposed image in the process the bigger the softer saturation Set the saturation of the overexposed image brightness Expressed in EV the brightness slider selects the increase in brightness mix Controls the mix of the overexposed image and the overall effect Examples This is the original image use it as reference For the changes below In this image used the default values and added 0 33EV to brightness for a little more light in the soft layer This version is the same as
195. nput image Caution When modules drastically modify hue e g when generating complementary colors this blend mode can result in strong color noise Lab lightness Only available with modules that work in the Lab color space this blend mode mixes light hess from the input and output images while color data are taken unaltered from the input image In contrast to blend mode lightness this blend mode does not involve any color space conversion and does not clamp any data In some cases this is less prone to artifacts in comparison to lightness Lab color 46 Only available with modules that work in the Lab color space this blend mode mixes Lab color channels a and b from the input and output images while lightness data are taken unaltered From the input image In contrast to blend mode color this blend mode does not involve any color space conversion and does not clamp any data In some cases this is less prone to artifacts in comparison to color HSV lightness Only available with modules that work in the RGB color space this blend mode mixes light ness from the input and output images while color data are taken only from the input image In contrast to blend mode lightness this mode does not involve clamping HSV color Only available with modules that work in the RGB color space this blend mode mixes col or from the input and output images while lightness data are taken only From the input imag
196. nt in the input zones to modify the zonemapping Shifting a control point proportionally expands the zones on one side and compresses the zones on the other side Any already existing control point stays in place effectively preventing changes to the zones beyond Use right click to remove a control point The preview shows the image broken down in zones When hovering above a zone on the zonebar that zone either from input or output is highlighted on the preview Examples 78 The original image Here the darker and lighter zones were compressed to increase contrast then the upper parts of darker zones were expanded to increase their visual impact 3 4 2 5 Local contrast Overview This module allows enhancing local contrast It uses 0 local contrast the unnormalized bilateral filter and works on the L 50 channel from Lab Usage Local contrast boosts details of your image much like the equalizer does see Sec tion 3 4 4 2 Equalizer However it is easier to use as it does not require you to work on different frequency bands coarseness Make the details you want to adjust finer or coarser contrast How strongly the algorithm distinguishes between brightness levels Increasing the value results in a more contrasty look detail Add or remove detail Higher values will increase local contrast Example Before After a little overdone to demonstrate the effect Use this sparingly to
197. nterpolation with data of the neighboring pixels For further reading see the Wikipedia article on the Bayer filter http en wikipedia org wiki Bayer_filter 71 As interpolation is prone to produce artifacts various different demosaic algorithms have been developed in the past Artifacts would typically be visible as moir like patterns when you strongly zoom into your image Currently darktable supports PPG AMAZE and VNG4 All these algorithms produce high quality output with a low tendency to artifacts AMAZE is reported to sometimes give slightly better results However as AMAZE is sig nificantly slower darktable uses PPG as a default VNG4 produces the softest results of the three algorithms but if you see maze artifacts try VNG4 to eliminate them There are a few cameras whose sensors do not use a Bayer filter Cameras with an X Trans sensor have their own set of demosaicing algorithms The default algorithm for X Trans sensors is VNG For noticeably better quality at the cost of slower processing choose Markesteijn 1 pass or for the best quality but the slowest processing Markesteijn 3 pass Some Further parameters of this module can activate additional averaging and smoothing steps They might help to reduce remaining artifacts in special cases Demosaic is always applied when exporting images Demosaic is done on monitor display only when zoom is greater than 50 or when the according preference setting demosaic
198. o covered in an extensive blog section that you can find on our homepage http www darktable org news about blog install resources development contact CATEGORY ARCHIVES Process HDR images using darktable Posted on October 6 2012 by dinamic Introduction This blog post will go through a simple workflow when working with high dynamic ranged images using darktable and the modules for processing you need use Darktable 1 1RC for this guide The example image used in the screenshots can be downloaded at following link AtriumMorning How to make an HOR image I m not going into details of the process of making an HDR image there are many guides out there Continue reading Posted in blog Tagged HDR processing workflow 7 Replies Geotagging in darktable Posted on September 23 2012 by houz For quite some time people have asked us for a way to geotag their images from within darbtable While that is a nifty feature for sure and really helpful when you take pictures outside of a studio we always had to say something along the lines of sorry we dont have that yet Some day however Henrik decided to give ita 215 9 1 darktable and memory darktable s memory requirements are high A simple calculation makes this clear IF you have a 20MPx image darktable for precision reasons will store this internally as a 4 x 32 bit Floating point cell for each pixel Each Full image of this size will need about 300MB of mem
199. odi Fication by the L channel tone curve It is designed to give an overall boost in color satura tion if the L curve gives a contrast boost Look at blend mode coloradjustment to adjust the strength of this effect see Section 3 2 6 Blending operators IF this combobox is set to manual you can modify color saturation using the curves in channels a and b Examples Original image Tone curve settings Please note how the center node of our b curve was shifted down to negative val ues This gives the image its blue tint TT 3 4 2 4 Zone system Overview Usage This module is another way to change the lightness 0 zone system Y of your image based on Ansel Adams system It al lows modification of a zone s lightness taking into ac count the effect on the adjacent zones It divides the lightness range into a user defined number of zones Following the concept of Ansel Adams the lightness based on the L channel from Lab is divided into a number of zones ranging from pure black to pure white These zones are displayed in a zonebar The number of zones can be changed by mouse scrolling on that bar defaults to 10 zones The zonebar is split horizontally with the upper part showing the zones of the module s output and the lower part the according zones of the module s input In its default state both parts are Fully aligned While the output zones are static you can left click and drag a control poi
200. oetz Wyatt Olson and many others darktable is free software you can redistribute it and or modify it under the terms of the GNU General Public License as published by the Free Software Foundation either version 3 of the License or at your option any later version darktable is distributed in the hope that it will be useful but WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE See the GNU General Public License For more details You should have received a copy of the GNU General Public License along with darktable IF not see the GNU homepage http www gnu org licenses The present user manual is under license cc by sa meaning Attribution Share Alike You can visit the creative commons page http creativecommons org about licenses to get more information Table of Contents Preface CO EMIS Manualer een shane neaeeass E a ea tenstessessacearecssdaneetam atiwiotees vii TW eOVETVIOW sie caes ewe ssa irosealerce ned cewane uses ices tana E el saan ana a tee eae anaes 1 le i Program INVOCAE ON eranen a R sateen 3 Al ls arkea OLED oo cauase at ceeacacusaveaseh vee che A avast ensueen saan ate 3 V2 LO tek oO FOG It DNA y oeenn eea EEE ROEE aes 4 12 Userin SI hl CO aiena a a a E E 6 kea e VIEWS eet e aa e A E tumene 6 I2 2s Sreen dayo UE ieni a T a 6 12 924 IMIS Ell D eane a a a r 7 We APE RENIN CS nae a E taaredetuatramusa soeivanasualosaesss 7 1 3 darktabte Das
201. of combination exclusive Any individual mask can exclude a pixel by setting its value to zero regardless of what the other individual masks do Once a pixel is excluded its value is 0 by any mask there is no way to include it again by any other individual mask An alternative way to combine masks is the Following we first invert each individual mask calculating 1 0 minus its value then we multiply these inverted masks and as a last step invert the Final mask again Now if one of the non inverted individual masks has a value of 1 0 at a pixel location the Final will also be 1 0 The Final mask can only reach a pixel value of 0 if all the individual masks have a value of 0 We call this way of combination inclusive Any individual mask can include a pixel by setting its value to 1 0 regardless of what the other individual masks do Once a pixel is included its value is 1 0 by any mask there is no way to exclude it again by any other individual mask These two combination methods alone would still be rather limiting We gain maximum Flexibility by allowing an additional inversion step for each individual mask This is gov erned by the polarity buttons E and B that you Find close to the individual channels Tog gling the polarity button of a mask inverts its values i e it recalculates the pixel values to 1 0 minus the original value Finally within the combine masks combobox you may once again invert the final result to F
202. ofiles by placing these in SDARKTABLE share darktable color out and SHOME config darktable color out SDARK TABLE is used here to represent your chosen dark table installation directory and SHOME your home di rectory A configuration parameter always try to use littlecms2 in darktable s core options see Section 7 2 Core options defines how darktable renders colors for display and export IF the configuration parameter is disabled darktable uses a simplified and very fast inter nal rendering algorithm IF the option is checked the external library littlecms2 http www littlecms com with higher accuracy and significantly higher processing overhead is used instead output intent Sets the rendering intent for output export You can easily override this setting whenever you do exports from lighttable mode perceptual Suited to pictures as it maintains the relative position of colors This is usually the best choice relative colorimetric Out of gamut colors are converted to colors having the same lightness but different saturation Other colors remain unmodified saturation Saturation is kept but lightness is slightly changed absolute colorimetric Keep the white point Only rendering with littelcms2 gives you a choice of rendering intent The option is hidden if darktable s internal rendering routines are used display intent Sets the rendering intent for your display See above for available options outp
203. og For now 4 2 2 Live view This panel gives you control of your camera s live view mode Functionality such as Focus setting rota tion adding guides and overlays are supported 4 2 3 Camera settings The camera settings section allows you to set up a camera settings capture job This can include sequence bracket and aa delayed captures You are also able to control other camera settings such as focus mode aperture shut ter speed ISO and white balance co additional properties 125 4 3 Examples This section contains examples of typical usages of tethering 4 3 1 Studio setup with screening This is a pretty common use case You have your studio and subject set up the camera is connected to your computer and tethering view is active in darktable You work at the camera and take images Whenever you want you can screen the image directly on your computer monitor instead of using the camera LCD for validation This workflow is efficient and effective since you can immediately review your captures instead of waiting until after the shoot when everyone is gone IF you re shooting a model this is a pretty nice way to pre view the captures with the client instead of fumbling around with your camera Working in the tethered mode can save you time and aggravation Set a session name shoot your images and they will save in the correct Film roll For the session for easy on site review 4 3 2 Capturing a time
204. ok if device Tahiti is free because it s Faster IF that s not the case all other devices in fact only the GTS450 are checked 9 2 9 OpenCL still does not run for me As has been said before OpenCL systems come with a huge variety of setups different GPU manufacturers different GPU models varying amounts of GPU memory different drivers different distributions etc Many of the potential problems will only appear with a very specific combination of those Factors As we developers of darktable on our computers only have access to a small Fraction of those variations please understand that we might not be able to Fix your specific problem There is not much we can do if there is no way for us to reproduce IF nothing else helps the best option might be to start darktable with darktable disable opencl In the end there is nothing in darktable which only runs on GPU Don t let OpenCL discour age you also darktable s CPU code is highly optimized for performance 2217 228 Index A artifact mitigation banding 49 97 105 114 black pixels 56 75 85 88 blue light sources 56 75 85 88 halos 67 90 magenta highlights 72 B banding 97 base curve 69 basic workflow 8 blending 43 blending operators 45 bloom 111 brightness 71 see also levels see also tone curve brush 48 C camera import 22 channel mixer 81 chromatic aberration 99 see also lens correction circle 48 clarity see eq
205. ol the look and feel of darktable width of the side panels in pixels This controls the size of side panels in pixels Side panels are Found left and right to the center view default 300 don t use embedded preview jpeg but half size raw Check this option to not use the embedded jpeg from the raw file but process the raw data This is slower but gives you color managed thumbnails default off ask before removing images from database Always ask the user before any image is removed from the database default on ask before erasing images from disk Always ask the user before any image file is deleted default on ask before moving images from film roll folder Always ask the user before any image file is moved default on ask before copying images to new film roll folder Always ask the user before any image file is copied default on number of folder levels to show in lists The number of folder levels to show in Film roll names starting From the right default 1 ignore jpeg images when importing film rolls When having RAW JPEG images together in one directory it makes no sense to import both With this flag one can ignore all jpegs Found default off recursive directory traversal when importing Film rolls Not only import images from the directory selected but recursively go through all subdi rectories as well default off creator to be applied when importing IF provided automatically add this string as a creator ta
206. old Sets the threshold for underexposure warning expressed as a percentage of the maximal brightness upper threshold Sets the threshold for overexposure warning expressed as a percentage of the maximal brightness 3 3 9 4 Filmstrip The optional Filmstrip can be used to quickly switch between images while remaining in the darkroom view The images viewed are the same as the ones in the lighttable view The Filmstrip can be switched on and off using the shortcut ctrl f You can scroll with your mouse to quickly navigate through the images and change the height of the Filmstrip panel by dragging its top 64 3 4 Modules Modules are organized into Five Functional groups basic tone color correction and ef Fect You either view all modules in one long list or instead click on a group to just display modules belonging to that group 3 4 1 Basic group The basic group of modules contains the modules for basic development These are ones you probably will use most often such as exposure white balance etc 3 4 1 1 Crop and rotate Overview Usage Flip angle This module is used to crop rotate and correct per O O spective distortions of your image You can overlay flip angle 0 00 your image with various helpful guidelines that assist ETET aae you using the tools automatic cropping yes Y aspect image guides none Y Some of the tools of this module namely adjustment of angle and correcti
207. on 7 1 GUI options Extracting an embedded thumbnail from the input image has the advantage of being very Fast However as those thumbnails were generated without knowing your display profile the colors may be rendered incorrectly You may notice differences when you open the image in the darkroom view where colors are corrected for your monitor As the thumbnail cache has a pre defined maximum size it will eventually get Filled up Then if new thumbnails are added old ones need to be dropped This typically passes un noticed to the user unless a too small cache size is selected In that case you might ob serve adverse effects like continuous regeneration of thumbnails each time you move in your collection Flickering of thumbnail images or even darktable becoming unresponsive while continuously generating new thumbnails and dropping them again A good choice of the cache size is 512MB or higher Please mind that the inherent limits of 32 bit systems will Force you to go For a much lower cache size see Section 9 1 darktable and memory For more details on these limitations 2 2 3 2 Skulls IF For some reason darktable is not able to generate a thumbnail it displays a skull Don t panic There are three main reasons for this to happen One possible cause is that the input image has been renamed or physically deleted From disk darktable remembers all images ever imported as long as they have not been removed from yo
208. on for both shadows and highlights you can also click the color preview box to bring up a common color picker dialog balance This parameter represents the ratio of toning between shadows and highlights For a value of 50 half of the lightness range in image is used for shadows toning and the other half For highlights toning compression 104 Compression is a percentage of total lightness range that is not affected by color toning Default value is set to 33 this is not the default behavior of an original splittoning which would be 0 compression The choice of 33 as a default is to invite you experimenting with these parameters and how it extends the original splittoning method Examples Original black and white image Splittoning with blue shadows and yellow highlights 3 4 5 4 Vignetting Overview This module is an artistic Feature which creates vi EJ vignetting Y gnetting modification of the brightness saturation scale 80 00 fall off strength at the borders brightness saturation horizontal center vertical center shape automatic ratio width height ratio dithering blend Usage The vignetting module has an extensive set of parameters to precisely tune its effect It also will display graphical controls within the image if the module is in focus Give it a try to get a feeling of how it works On screen controls and parameter sliders will stay in sync This module is known to provoke banding art
209. ons of perspec tive distortion will require the original image data to be interpolated For best sharpness results set lanczos3 as pixelinterpolator in core options see Section 7 2 Core options Whenever the user interface of this module is in focus you will see the full uncropped image overlayed with handles and guiding lines First off select what aspect ratio you want and size the crop boundaries by dragging bor der and corner handles Use the button right of the aspect box to swap between portrait and landscape mode You can move around the crop rectangle by holding down left mouse button and move around When you are done and want to execute the crop just give Focus to another module or double click into the image base You can at any time change your crop area by just revisiting this module This tool is used to Flip the image on the horizontal vertical or both axis This tool corrects the rotation angle helping you level an image You can either set a nu merical value or use your mouse directly on the image To use your mouse right click hold it down and draw a line along the horizon as soon as you release the mouse button the image is rotated so the line you drew matches the horizontal axis keystone This toolis used to correct perspective distortions in your image Useful for example when you shoot a high building from ground with a short Focal length aiming upwards with your camera The combobox lets you sele
210. oom CONCE DUS auaa axel tees A EA EE EEE 39 3 2 1 Pixelpipe module order and history stack sesesesesesesesesesseseseses 39 3 22 Mtera ctiNo WIC MOduUlEsS oriee or a a a r E e E 39 3 23 Module Drasals serrer onno eea e a e a GA 41 5 24 Multiple Instances eoan a a a a E OR 42 B25 BLOWIN keien a E a A a REE a 43 3 2 6 Blending Operators eeri aa a aa a a 45 SA lke DOWN MaS eena a a aT ea 47 23 28 Paramete MaSK ontana naa aa a aaa eee 50 3 2 9 Combining drawn and parametric masks sesesesessesesesesessesesesesese 53 32 10 Color management asrau dae r a E ET 54 5 oO DAFKFOOIN Daneli aioa a a ah et et ata r hh hhc cies 57 Boe la IWAVIG AO Mens ctacerrnc ue seo sesh aice tenes sch pce ling E goe iting uate se eae 57 5 922 SNAP NOTS cx ticieat tailors bie A A lobe euuaicia ASEN 57 B35 PS COT yV SUCK ocer tenei A TE 57 3A GlODAl COLOF DICKET enia A A rh ae ie ahs 58 535s Mask Manager eiee a rn a a ea aaea 59 3 36 ISCOGLAIN aeaa a AE 61 Ble TO GUE rO UDS ore N A EE 61 33 8 MOr eE modules jeu ss staid enr a a a a aa ai aa 62 SS BOR Om DANE a ush scat tent eta eee en sh ace tie hess 63 5 4 MOGUIES inina a Aa a A A ees 65 34 le Basi OrOUD setana rS T TE 65 34 2 TONE OCOD sires naa r ace eren eau when 14 334 3 COLOP Oro UD moie deiei aaie a eera aa Mecca matiedaateiodeusnsanntons 81 3AA CONECHONOIrOUD oaa a A E E 90 ASLEEP eia E 100 BS EXIME Saan anaa gl ac eee a aa aa r tet ads 117 3 5 1 Converting to black and white
211. opacity values get inverted 100 be comes 0 and vice versa You need this Feature when combining drawn and parametric masks see Section 3 2 9 Combining drawn and parametric masks mask manager More functionality to control the interaction of multiple shapes within a mask can be Found in the mask manager panel see Section 3 3 5 Mask manager Here you can give individual names to your shapes which will help you to keep track of your shapes You can also select individual shapes for editing a helpful feature if your masks happens to con tain several shapes with overlapping control elements 3 2 8 Parametric mask The parametric mask Feature formerly called conditional blending offers fine grained selective control over how individual pixels are blended It does so by automatically gen erating an intermediate blend mask from user defined parameters These parameters are color coordinates not the geometrical coordinates used in drawn masks The parametric mask is a powerful tool with a certain level of complexity 3 2 8 1 Overview 50 For each data channel of a module Lab RGB and additionally For several virtual data chan nels e g hue saturation users can construct a per channel opacity Function Depending on the pixel s value For this data channel this Function determines a blending Factor be tween 0 and 1 or 100 for that pixel Each pixel of an image thus has different blending factors for e
212. ormat_data_pfm dt_type Type object describing parameters to export to pfm Attributes e parent types dt_imageio_module_ format _t 8 2 2 8 types dt_imageio_module_format_data_ jpeg dt_type Type object describing parameters to export to jpeg Attributes e parent types dt_imageio_module_ format _t types dt_imageio_module_format_data_jpeg quality number The quality to use at export time Attributes e write 8 2 2 9 types dt_imageio_module_format_data_ppm dt_type Type object describing parameters to export to ppm Attributes e parent types dt_imageio_module_ format _t 8 2 2 10 types dt_imageio_module_format_data_webp dt_type 197 Type object describing parameters to export to webp Attributes e parent types dt_imageio_module_ format _t types dt_imageio_module_format_data_webp quality number The quality to use at export time Attributes e write types dt_imageio_module_format_data_webp comp_type cYyYDeSs COMo_ type E The overall quality to use can be one of webp lossy or webp_ lossless Attributes e write types dt_imageio_module_format_data_webp hint types hint A hint on the overall content of the image Attributes e write 8 2 2 11 types dt_imageio_module_format_data_j2k dt_type Type object describing parameters to export to jpeg2000 Attributes e parent types dt_imageio_module_format_t types dt_imageio_module_format_data_j2k quality number The quality to use at export time Attributes e write t
213. ory As we want to process the image we will at least need two buffers for each module one for input and one for output IF we have a more complex module its algo rithm might additionally require several intermediate buffers of the same size Without Further optimization anything between 600MB and 3GB would be needed only to store and process image data On top we have darktable s code segment the code and data of all dynamically linked system libraries and not to Forget Further buffers where darktable stores intermediate images for quick access during interactive work mip map cache All in all darktable would like to see a minimum of about 4GB to run happily 9 1 1 Total system memory From what I said before it is evident that your computer needs a sane memory setup to properly run darktable We suggest that you have a least 4GB of physical RAM plus 4 to 8GB of additional swap space installed The latter is required so that your system can swap out temporarily unneeded data to disk in order to free physical RAM Theoretically you could also run darktable with lower amounts of physical RAM and bal ance this with enough swap space However you should be prepared that your system could then heavily thrash as it reads or writes data pages to and from the hard disk We have positive reports that this Functions well for several users but it still might get extremely slow for others 9 1 2 Available address space Besides
214. ottom panel The bottom panel provides quick access to apply presets and styles to your image and allows to activate the over underexposure warning You can also activate a Filmstrip For quick navigation within the current collection 3 3 9 1 Quick access to Favorite presets Clicking the E icon opens a combobox that gives you quick access to your favorite module s presets Click on the preset name to apply it to the image 3 3 9 2 Quick access to styles Clicking the EJ icon opens a combobox with your styles Hovering with the mouse over a style name opens a tooltip showing the involved modules Click on a style name to apply that style to the image 3 3 9 3 Over underexposed warning By clicking the Z icon an over underexposed warning is toggled on or off Pixels outside the dynamic range close to pure white or close to pure black are prominently displayed in a signal color You can also activate the over underexposure warning with the keyboard shortcut o Right clicking on the icon opens a dialog with config color scheme uration parameters lower threshold upper threshold color scheme In the default color scheme underexposed pixels are shown in blue and overexposed pixels in red These colors are easy to identify in most cases In some cases you may want to change the color scheme to black amp white or purple amp green eg if you experience overexposed highlights in red blossoms 63 lower thresh
215. ou can apply a GPX track Click the correspond ing button and navigate to the GPX file Before con Firming that dialog you should select the correspond ing time zone for your camera in the drop down menu Should you ever make a mistake with the time zone selection you can just come back and reapply the GPX file with a different time zone 31 2 3 10 Metadata editor Edit metadata of an image like title description cre 3 metadata editor ator publisher or rights You can define your own pre sets if you want to apply specific settings Frequently 2 3 10 1 Usage clear Delete existing metadata from the selected image s apply Apply new settings as defined in the Fields above to the selected image s 2 3 11 Tagging This panel is for managing tags on images Tags are tagging stored in both sidecar files xmp and within the darktable for mat er2 darktable database for a faster access The panel is divided into two parts the upper part contains the tag s currently attached to the image under the cur sor or the selected image s if the mouse is outside the lighttable The lower part contains a list of all available tags in the database which can be filtered in the text box above New tags get added to the list either by typing into the text box and pressing the new button or if an automatically generated tag gets attached to an image or on import of al ready tagged images darktable sorts
216. over the text label or entry box to display a popup tool tip All configuration para meters are explained in Chapter 7 Preferences and settings 1 3 darktable basic workflow This section describes a typical darktable workflow which novice users may take as a start ing point We describe how to get an image into darktable the basic steps of a raw devel opment workflow and how to export the Final result 1 3 1 Importing images To begin with darktable you first need to import images The import module is in the left pane of the lighttable view Section 2 3 1 Import You can either import from the Filesystem or if darktable supports your camera model directly From camera 1 3 1 1 Importing images from filesystem When importing From disk you can import either a single image or a Folder darktable will analyse its content detect images that are already imported and only import new images 1 3 1 2 Importing from camera Connect your camera to your system IF your distribution tries to automount it select the option to abort the mount operation Otherwise the camera will be locked and not acces sible From within darktable IF you don t see your camera in the import pane hit the scan For devices button Your camera will then appear in the same pane with additional choic es import and tethering 1 3 2 Basic development steps 1 3 2 1 Introduction This section will guide you through the basics of developing an im
217. p an import dialog showing the images on camera that can be selected For import into a Film rollin darktable You define the base directory for storing imported images and the naming pattern of sub directories and individual images in the preferences dialog see Section 7 3 Session op tions Tethered shoot Tethering is used to integrate darktable with your camera While you take images with your camera they are automatically imported into darktable so you can review the result of the shoot You can also setup remote capture jobs controlling the number of images and time between captures along with camera settings such as exposure time aperture and more IF supported by your camera tethering will take you into the capture view for tethered shooting Read more about tethering in Chapter 4 Tethering 2 3 1 3 Supported File Formats darktable is Focused on managing and developing camera RAW files It supports a huge number of File Formats from various camera manufacturers In addition darktable can read specific low dynamic range and high dynamic range images mainly For data exchange be tween darktable and other software In order for darktable to consider a File For import it must have one of the Following ex tensions case independent 3FR ARW BAY BMQ CAP CINE CR2 CRW CS1 DC2 DCR DNG ERF FFF EXR IA IIQ JPEG JPG K25 KC2 KDC MDC MEF MOS MRW NEF NRW ORF PEF PFM PNG PXN QTK RAF RAW RDC
218. panel The history stack records your workflow in the order in which you made changes to the pipeline It allows you to go back to an earlier stage of development if needed The history stack represents your personal workflow and is not to be confused with the sequence in which modules are applied in the pixelpipe see above For more details on the history stack see Section 3 3 3 History stack 3 2 2 Interacting with modules 39 A module has an expander bar kki aie Clicking on the name of the module expands the module s GUI with all parameters In its default setting darktable will only expand one GUI at a time IF you click the expander bar of another module the previous GUI gets collapsed IF you want to see more than one GUI expanded you may expand Further modules with shift click all previously expanded GUIs remain opened The expander bar behavior on click and shift click respectively is controlled by a preference setting in gui options see Section 7 1 GUI options Expanding a module does not activate it You need to click the J icon to turn a module on or Off Icon Hl accesses the module s available presets or creates a new preset from your current settings see Section 3 2 3 Module presets The kd icon is used to reset the module parameters to their default values Many of darktable s modules can have multiple instances each with different settings Click on the BJ icon to generate new insta
219. parameters to get it running IF you install Fresh darktable will detect your system and set conservative values by default However if you upgrade darktable from an older version e g coming From 0 9 3 and going to 1 0 chances are you have unfavorable settings in your preferences The consequences might be darktable aborting due to allocation Failures or very typically darktable not being able to properly import a new Film roll As a frequent symptom you get skulls displayed instead of thumbs For many of your pictures IF this is the case take a minute to optimize the preference settings in this case You will Find them under core options Section 7 2 Core options in darktable s preference di alog You should also find these parameters as configuration variables in SHOME config darktable darktablerc and edit them there Here is a short explanation of the relevant parameters and their proposed settings number of background threads This parameter defines the maximum number of threads that are allowed in parallel when importing Film rolls or doing other background stuff For obvious reasons on 32 bit systems you can only have one thread eating resources at a time So you need set this parameter to 1 anything higher will kill you For the same reason you also must set the number of parallel export threads to 1 host memory limit in MB For tiling This parameter tells darktable how much memory in MB it should assume i
220. ple we use this oper ator to imprint the path with a gradient difference This set operator is depicted by the I symbol In the non overlapping area the existing mask is un changed In the resulting mask pixels get selected on ly if they are selected in the existing mask but notin the added shape This set operator can be chosen if you want to cut out a region from within an exist ing selection exclusion This set operator is depicted by the EJ symbol The resulting mask has all pixels selected that are either selected in the existing mask and not in the added shape or vice versa This is equivalent to an exclusive n or 3 3 6 Histogram This shows a histogram of the developed image s light levels In its default state curves for all three RGB color channels are displayed You can toggle the colored squares to enable or disable specific color channels A curve button is also provided to toggle between linear view logarithmic view and wavefront view The histogram is directly linked to the exposure mod ule described in Section 3 4 1 5 Exposure and you can operate some of the exposure module s con trols from the histogram You can left click towards the right hand side of the histogram and then drag right to increase or drag left to decrease the expo sure In a similar manner you can control the black level by clicking and dragging in the left hand side Double clicking in the histogram rese
221. processing of modules like shadows and highlights monochrome local con trast or global tonemap or if you even get intermittent system Freezes These recommendations do not apply to the more recent Radeon HD7xxx series with GCN architecture Besides being very Fast in terms of GPU computing they normally run out of the box You only might consider to try some of the performance optimization options which are described in the Following section 9 2 7 OpenCL performance optimization There are some configuration parameters in SHOME config darktable darktablerc that help to Finetune your system s OpenCL performance Performance in this context mostly means the latency of darktable during interactive work i e how long it takes to reprocess your pixelpipe For a comfortable workflow it is essential to keep latency low In order to get profiling info you start darktable from a terminal with darktable d opencl d perf After each reprocessing of pixelpipe caused by module parameter change zooming pan hing etc you will get the total time and the time spent in each of our OpenCL kernels 223 The most reliable value is the total time spent in pixelpipe Please note that the timings given for each individual module are unreliable when running the OpenCL pixelpipe asyn chronously see opencl_async_pixelpipe below To allow for a Fast pixelpipe processing with OpenCL it is essential that we keep the GPU busy Any interrupts or a stal
222. profile sup port for export sRGB Adobe RGB XYZ and linear RGB e A collect module allows you to execute Flexible database queries search your images by tags image rating stars color labels and many more Filtering and sorting your col lections within the base query or simple tagging by related tags are useful tools in your every day photo workflow e Import a variety of standard raw and high dynamic range image Formats e g JPG CR2 OpenEXR PFM e darktable has a zero latency Fullscreen zoomable user interface through multi level software caches e Tethered shooting e The powerful export system supports Picasa webalbum flickr upload disk storage 1 1 copy email attachments and can generate a simple html based web gallery darktable allows you to export to low dynamic range JPEG JPEG2000 PNG TIFF 16 bit PPM TIFF or linear high dynamic range PFM EXR images e darktable uses both XMP sidecar files as well as its Fast database for saving metadata and processing settings All Exif data is read and written using libexiv2 e darktable comes with more than 50 image operation modules which cover everything From basic operations tonal value changes color manipulation correction of common image defects to artistic effects e Many darktable modules can be combined with blending operators for even more de velopment options A powerful mask feature gives you fine control on module s effect to different parts
223. r drawn and parametric mask are selected an ad ditional combobox is shown that controls how the individual masks are combined to Form the final mask Details on the combination of individual masks can be found in Sec tion 3 2 9 Combining drawn and parametric masks Additional controls When blending with a mask there are some additional options to deal with the Final mask you may blur the mask temporarily disable it or display it as an overlay image mask blur Blurring the mask creates a softer transition between blended and unblended parts of an image and avoids artifacts The mask blur slider controls the radius of a gaussian blur 44 applied to the final blend mask The higher the radius the stronger the blur or set to 0 For an unblurred mask temporarily switch off mask Sometimes it is useful to visualize the module s effect without the mask taking action You can do so by clicking on the amp symbol which will temporarily deactivate the mask the selected blend mode and opacity remain in effect Switch this button on and off to see if the mask is acting on the image as intended display mask Clicking on the EJ symbol will display the current mask as a yellow overlay over a black and white version of your image Solid yellow indicates an opacity of 100 a Fully visible gray background image without yellow overlay indicates an opacity of 0 3 2 5 3 Examples Texturing an image The watermark module
224. r RGB color space You can also activate a color picker by pressing i and take a color probe from your image 103 Examples Example image with a user defined Frame 3 4 5 3 Splittoning Overview Usage darktable s splittoning method creates a two color d 0 split toning Y linear toning effect where the shadows and high lights are represented by two different colors In the example image below you can see an original black and white image and one where a splittoning effect is applied with blue in shadows and a yellowish color ere in highlights e saturation n 0 50 highlights Compared to traditional splittoning our module has more parameters to influence its be havior We have parameter balance which offsets the 50 gray level in your image at your choice more to the shadows or more to the highlights Additionally with parameter compression you can compress toning in the shadows and highlights and leave a gap in the mid tones which remain untouched by the effect The splittoning module does not convert images to black and white and has limited ben efits on color images So if you want to do traditional splittoning use the monochrome module see Section 3 4 3 6 Monochrome to make the image black and white before playing around with splittoning effect shadows and highlights color These controls are used to set the color of the splittoning effect you select the desired color and saturati
225. r image collection when dis played in lighttable view You can combine images into a group by selecting them and clicking the group button in the selected image s panel Section 2 3 6 Selected image s or by typing ctrl g Like wise you can remove selected images from a group by clicking the ungroup button or typing shift ctrl g Images generated by duplicating an existing one are automatically grouped If you import images From the file system or camera images with the same base name but different extensions eg IMG_1234 CR2 and IMG_1234 JPG will Form a group Images which are members of a group are labeled with a G symbol in their thumbnails The group button W in the top panel of the lightroom view toggles grouping mode on and off IF grouping is off each image is displayed as an individual thumb IF grouping is on images of a group are collapsed which means they are represented by a single thumbnail This thumbnail you see is called the group head IF you press the G symbol in the group s thumbnail only this group gets expanded if you then expand another group the First group collapses To collapse an expanded group again just click on the G symbol of its group head An expanded group in the Filemanager mode of light table view is indicated by an orange frame which ap pears as soon as your mouse pointer hovers over one of the images You can define which image constit
226. rd print Function to print a string That s nice and all but we can do better than that To access the darktable API you First need to require it and save the returned object in a variable Once this is done you can access the darktable API as subfields of the returned object All of this is documented in Section 8 2 1 darktable local darktable require darktable darktable print_error Hello World Run the script and nothing happens The Function darktable print_error is just like print but will only print the message if you have enabled lua traces with d lua on the command line This is the recommended way to do traces in a darktable lua script 8 1 3 Printing labeled images This first example showed us the very basics of lua and allowed us to check that everything is working properly Let s do something a little bit more complex Let s try to print the list of images that have a red label attached to them But first of all what is an image 152 local darktable require darktable local debug require darktable debug print darktable debug dump darktable database 1 Running the code above will produce a lot of output We will look at it in a moment but First let s look at the code itself We know about requiring darktable Here we need to separately require darktable debug which is an optional section of the API that provides helper Functions to help debug lua scripts darktable database is a table pro
227. reduce noise There is raw denoise denoising based on bilateral filter denoising based on non local means and equalizer which is based on wavelets IF your camera is not yet supported by profiled denoise denoising based on non local means is probably the most convenient as it allows you to treat color and luminance noise separately 1 3 2 5 Fixing spots Sometimes you will need to remove spots caused by sensor dirt The spot removal module is at hand and can also correct other disturbing elements like skin blemishes IF your cam era has stuck pixels or tends to produce hot pixels at high ISO values or longer exposure times have a look at the hot pixels module for automatic correction 1 3 2 6 Geometrical corrections Quite Frequently you want to only show part of the captured scene in your image e g to take away some disturbing Feature close to the Frame In other cases the horizon in the image may need levelling or there are perspective distortions All this can be corrected in the crop and rotate module IF you need to correct typical camera lens flaws like cush ion distortion transversal chromatic aberrations or vignetting there is a lens correction module 1 3 2 7 Bringing back detail Digital RAW images often contain more information than you can see at First sight Espe cially in the shadows of an image there are lots of hidden details The shadows and high lights module helps bring these details back into visible tonal
228. rocessing quality has led to all calculations being done on 4 x 32bit Floating point numbers This is slower than ordinary 8 or 16bit integer algebra but eliminates all problems of tonal breaks or loss of information A lot of hand optimization has been invested to make darktable as Fast as possible IF you run a current version of darktable on a modern computer you might not notice any slow ness However there are conditions and certain modules where you will Feel or hear from the howling of your CPU Fan how much your poor multi core processor has to struggle That s where OpenCL comes in OpenCL allows us to take advantage of the enormous power of modern graphics cards Gamer s demand for high detailed 3D worlds in modern ego shooters has fostered GPU development ATI NVIDIA and Co had to put enormous processing power into their GPUs to meet these demands The result is modern graphics cards with highly parallelized GPUs to quickly calculate surfaces and textures at high Frame rates You are not a gamer and you don t take advantage of that power Well then you should at least use it in darktable For the task of highly parallel Floating point calculations modern GPUs are much faster than CPUs That is especially true when you want to do the same few processing steps over millions of items Typical use case processing of megapixel images 9 2 2 How OpenCL works As you can imagine hardware architectures of GPUs can var
229. rt path St rang then darktabpe print_error scp failed for tostring image end end Darktable will look for scripts Following the normal lua rules in the standard directories plus SCONFIGDIR 1lua lua So our script can be called by simply adding require sco storage in the luarc file A couple of extra notes The Function darktable configuration check_version will check compatibility For you the will turn into your script s name and 2 0 0 is the API version you have tested your script with You can add multiple API versions if you update your script For multiple versions of darktable Make sure to declare all your Functions as local to not pollute the general namespace Make sure you do not leave debug prints in your code darktable print_error in particular allows you to leave debug prints in your final code without disturbing the console You are free to choose any license for your script but scripts that are uploaded on darktable s website need to be GPLv2 Once you have filled all the Fields checked your code you can upload it to our script page here http darktable org redmine projects darktable wiki LuaScripts 8 1 7 Calling Lua from DBus It is possible to send a lua command to darktable via its DBus interface The method org darktable service Remote Lua takes a single string parameter which is interpreted as a lua command The command will be executed in the current lua context and should return
230. rted into darktable the database entries take precedence over the XMP file Subsequent changes to the XMP file by any other software are not visible to darktable any changes get overwritten the next time darktable synchronizes the File This behavior can be changed in the preferences dialog see Section 7 2 Core options On request darktable looks for updated XMP files at startup and offers a choice whether to update the database or overwrite the XMP file 2 2 8 Importing sidecar files generated by other applications 20 When importing an image darktable automatically checks if this is accompa nied by a sidecar file Other than the formats lt basename gt lt extension gt xmp and lt basename gt _nn lt extension gt xmp darktable also checks for the presence of a File in the Form lt basename gt xmp darktable s own sidecar files are always stored in the first for mat the latter one would only be read not overwritten At present darktable is able to deal with the Following metadata of Lightroom generated sidecar files during the import phase e tags and hierarchical tags e color labels e ratings e GPS information In addition darktable has been designed to help migrate some image operations from specific other applications The aim is not to make darktable a drop in replacement for any other software it s just meant to help you recover part of the work you have invested into your image in case
231. s available to store image buffers during module operations IF an image can not be processed within these limits in one chunk tiling will take over and process the image in several parts one after the other Set this to the lowest possible value of 500 as a starting point You might experiment later whether you can increase it a bitin order to reduce the overhead of tiling minimum amount of memory in MB for a single buffer in tiling This is a second parameter that controls tiling It sets a lower limit For the size of in termediate image buffers in megabytes The parameter is needed to avoid excessive tiling in some cases for some modules Set this parameter to a low value of 8 You might tentatively increase it to 16 later 217 memory in megabytes to use for mipmap cache This controls how many thumbnails or mip maps can be stored in memory at a time As astarting point set this to something like 256MB To avoid the problem of memory Fragmentation during longer runs of darktable the new caching scheme frontloads the memory costs and allocates this cache once at the beginning Some Linux kernels use over committing memory allocation which means you don t immediately pay for all of the memory in terms of RSS resident set size the non swapped physical mem ory but in any case you pay for the address space As explained before this poses a problem for 32 bit systems and will at First sight appear as a regression over the 0 9 3 style
232. same group as the image types dt_lua_image_t group_ leader types dt_lua_image_t The image which is the leader of the group this image is a member of types dt_lua_image_t local_copy boolean True if the image has a copy in the local cache Attributes e write types dt_lua_image_t drop_cache 194 self function drops the cached version of this image This Function should be called if an image is modified out of darktable to force DT to re generate the thumbnail Darktable will regenerate the thumbnail by itself when it is needed self types dt_lua_image_t The image whose cache must be droped 8 2 2 2 types dt_imageio_module_format_t dt_type A virtual type representing all Format types types dt_imageio_module_format_t plugin_name SsErinG A unique name for the plugin types dt_imageio_module_format_t name string A human readable name for the plugin types dt_imageio_module_format_t extension string The typical filename extension for that Format types dt_imageio_module_format_t mime Erg The mime type associated with the format types dt_imageio_module_format_t max_width number The max width allowed for the format 0 unlimited Attributes e write types dt_imageio_module_format_t max_height number The max height allowed for the format 0 unlimited Attributes e write types dt_imageio_module_format_t write_image self function image types dt_lua_image_t filename string
233. scale This slider allows you to adjust the scaling factor of your image Pressing the auto scale button right to the slider will let darktable find the best Fit to avoid black corners mode The default behavior of this module is to correct lens flaws Switch this togglebutton to distort in order to simulate the behavior of a specific lens inverted effect TCA red This slider allows to override the correction parameter for TCA You can also use this slider to manually set the parameter in case the lens profile does not support TCA correction Look out for colored seams at features with high contrast edges and adjust this parameter and the following one to minimize those seams TCA blue This slider allows to override the correction parameter for TCA You can also use this slider to manually set the parameter in case the lens profile does not support TCA correction corrections done You will sometimes observe that for a given camera lens combination only part of the possible corrections distortion TCA vignetting are supported by lensfun s profiles This message box will tell you what corrections have actually been applied 3 4 4 7 Scale pixels 95 Overview Usage Some cameras like the Nikon D1X have rectangu aso scale pixels lar instead of the usual square sensor cells Without automatic pixel scaling correction this would lead to distorted images This module applies the needed scaling darktable detects
234. shapesused the selected shape and afterwards change its prop 000 B erties invert mash off Y mask blur 0 0 eg You leave edit mode by clicking on the symbol You can at any time go back to edit mode and do further adjustments by clicking the edit symbol again In edit mode you can also remove a shape by right clicking on it the shape is removed from the current mask but it s still in the list of defined shapes IF you ctrl click on the edit mode symbol you enter a restricted edit mode Certain actions like dragging a complete shape or changing its size are blocked Only Finetuning changes like dragging a node are allowed 47 brush circle ellipse 48 Currently Five shapes are implemented Clicking the ZA symbol adds a brush stroke Start drawing by left clicking into the canvas and moving the mouse while keeping the button pressed The brush stroke is finalized once you release the mouse button Brush size hardness and opacity can be changed by scrolling shift scrolling and ctrl scrolling respectively either before you start drawing or at any time on your way IF you have a graphic tablet with pen pressure sensitivity darktable can apply the recorded pen pressure to certain attributes of the brush stroke See Section 7 1 GUI options For more details On lifting the tablet pen or releasing the left mouse button the drawn figure is convert ed into a number of connected nodes which define the shape A co
235. sible to the system s dynamic loader 1d so e libOpenCL so will read the vendor specific information file etc OpenCL ven dors nvidia icd to Find the library which contains the vendor specific OpenCL im plementation e The vendor specific OpenCL implementation comes as a library libn vidia opencl so 1 which in our case is a symbolic link to libn vidia opencl so 331 89 e libnvidia opencl so 1needs to talk to the vendor specific kernel modules nvidia and nvidia_uvmvia device special files dev nvidia0 dev nvidiact1 and dev nvidia uvm At system startup the required device special Files dev nvidia need to be created If this does not happen on your system by default the easiest way to set them up and make sure all modules are loaded is installing the nvidia modprobe package which at the time of this writing is only available For utopic but works well with trusty and Mint 17 You can grab it at this site http packages ubuntu com utopic nvidia modprobe A user account which wants to make use of OpenCL from within darktable needs to have read write access to NVIDIA s device special Files On some systems these Files allow world read write access by default which avoids permission issues but might be debatable in terms of system security Other systems restrict the access to a user group e g video In that case your user account has to be member of that group To summarise the packages which n
236. stop absorbance ND2 1 0 3 ND4 2 0 6 ND8 3 0 9 ND400 9 2 1 compression transmittance 50 25 12 5 0 195 Set progressiveness of the gradient A low value creates a smooth transition whereas a high value makes the transition abrupt hue Set the hue to add a color cast to the gradient saturation Set the saturation to add a color cast to the gradient position You can set the position of the gradient directly on the image by moving the white line For fine tuning you can also use the rotation slider Negative values turn clockwise Examples Here is an example that shows various options of darktable s graduated density filter This is the original image with a pretty overexposed sky use it as reference for the changes below And now we have added a neutral ND8 filter which does a pretty good job on the image 115 116 yyy And at last we added an orange colored filter rotat ing it 180 degrees applying it on water trees for a more artistic use of the filter darktable s graduated density filter is a powerful tool Nevertheless hardware Filters have some advantages over a pure software solution With a physical GND Filter you can in Fact reduce the dynamic range of your scene to make it better Fit the limits of your camera Sensor In this example a hardware GND filter Hitech NDO 6 soft edge helped to prevent over exposure in the sky and tree tops while at the same time getting a well
237. t e image rating isa field of any image that gives its rating between 0 and 5 stars 1 means rejected e darktable gui action_images is a table containing all the images of interest Darktable will act on selected images if any image is seleced and on the image under the mouse if no image is selected This Function allows to easily Follow darktable s UI logic in lua 155 IF you select an image and press your shortcut a couple of time it will work correctly at First but when you have reached five stars darktable will start showing the Following error on the console LUA ERROR rating too high 6 stack traceback EE ae 2 C in function newindex pf Conk LOdE lua roy EO a Tuner ON lt 7 COoneiodir _Luarce 1 gt LUA ERROR 4 rating too high 2 6 This is lua s way of reporting errors We have attempted to set a rating of 6 to an image but a rating can only go as high as 5 It would be trivial to add a check but let s go the complicated way and catch the error instead darktable register_event Shortcut function event shortcut local images darktable gui action_images for _ v in pairs images do result message pcall function VaePebang e Pat Ling I end if not result then darktable print_error could not increase rating of image tostring v message end end end Increase the rating of an image pcall will run its first argument and catch any exception thrown by it IF there is no ex
238. t clamp in between unbounded colors but treat them just like any other color data 55 In darktable there is no technical requirement for clamping due to the Fact that we are using Floating point arithmetics for all processing steps unbounded values can be passed along like any other value until the Final color conversion module makes sure that they are transferred into the most reasonable color within the selected output color space Therefore darktable avoids clamping as far as the underlying algorithms allow 3 2 10 3 Possible color artifacts 56 That said there are some infrequent situations which still can lead to problematic results unless the user takes some action Some modules in Lab color space like levels and mono chrome need to rely on the Fact that the L channels carries all lightness information and the a and b channels purely represent chroma and hue Unbounded colors with negative L values are especially problematic to these modules and can lead to black pixel artifacts It has been found that highly saturated blue light sources in the image frame are hot can didates for pixels with negative L values IF you are engaged in stage photography you should pay close attention to image areas like that In order to mitigate that issue the input color profile module see Section 3 4 3 10 Input color profile has a gamut clipping option It is off by default but can be activated in case you observe artifacts Depending on
239. ted You now gradually change the parametric mask sliders to exclude parts of your image as needed or you directly draw shapes on the canvas to specifically exclude these areas For your convenience you find in the parametric masks GUI a toggle button that inverts all channel polarities and toggles between inclusive and exclusive mode in the combine masks combobox For novice users it is recommended to stick to these two use cases This implies that you should decide beforehand how you want to construct your mask Advanced users will Find their way to take advantage of the many possible combinations of polarities and mask combination modes 3 2 10 Color management 54 The darkroom employs a Fully color managed workflow e Input color specifications are taken from embedded or user supplied ICC profiles or in case of raw files alternatively from a library of camera specific color matrices e darktable automatically reads the display profile of your monitor if properly config ured for an accurate color rendition on screen Multi screen setups are fully supported as long as asystem service like colordis in place and properly set up to inform darktable about the correct monitor profile e Output files can be encoded in one of darktable s built in profiles like sRGB http en wikipedia org wiki SRGB or AdobeRGB compatible http en wikipedia org wi ki Adobergb or into any other output color space that the user supplies
240. ter to library is usefull here if you don t want to work on your personal library 159 8 2 Lua API To access the darktable specific Functions you must load the darktable environment darktable require darktable All Functions and data are accessed through the darktable module This documentation for API version 2 0 0 dev 8 2 1 darktable The darktable library is the main entry point for all access to the darktable internals 8 2 1 1 darktable print PU Orr message string Will print a string to the darktable control log the long overlayed window that appears over the main panel message string The string to display which should be a single line 8 2 1 2 darktable print_error PUNCH Lon t message string This Function will print its parameter if the Lua logdomain is activated Start darktable with the d lua command line option to enable the Lua logdomain message string The string to display 8 2 1 3 darktable register_event FUNnCELON event_type string Callback Lunceion gt variable This Function registers a callback to be called when a given event happens Events are documented in the event section event _type Suen gam eke 160 The name of the event to register to callback LUNnCEAON The Function to call on event The signature of the Function depends on the type of event variable Some events need extra parameters at registration time these
241. the input image needs to hold an embedded JPEG thumbnail which is the case For most RAW files Sometimes pressing z or ctrl z may not reveal an immediate effect in that case please click into the center area and press the corresponding key again Fully zoomed in image view while holding down the ctrl z key with indication of the areas in focus Focus detection is based on an embedded JPEG thumbnail of the original RAW File independent of any process ing steps within darktable 15 2 2 Lighttable concepts This section explains some of the underlying concepts on how darktable organizes images in the lighttable 2 2 1 Film rolls The basic element for organizing images in darktable is called a film roll a kind of virtual Folder Whenever you import images from disk the images are organized in a film roll whose name is derived from the name of the disk Folder Re importing a disk Folder will add any new images to the existing Film roll images already present in the film roll are not touched It is important to note that importing images in darktable does not involve a physical copy step Importing a Folder into darktable is therefore nota backup operation of that Folder 2 2 2 Collections darktable offers a versatile Feature to organize your images according to various user de Fined selection criteria A set of images which is defined by a specific combination of se lection criteria is called a collection The most basic k
242. the list of tags by relevance and frequency of usage Hierarchical tags are supported and can be create using the pipe symbol As you may notice there are automatically created tags like darktable exported or dark table styles your style which keep track of your actions and let you easily find already exported images or images with specific styles applied Tip ctrl t opens a small text box at the bottom of the central view for quickly tagging your selected images by typing a tag phrase and hitting return 2 3 11 1 Usage attach Attach the selected tag from the list below to all selected images 32 detach new delete Detach the selected tag From all selected images This also can be done by double clicking the specific tag Create a new tag for the list Delete a tag From the list and From all images A warning will be displayed on how many images have this tag attached Take this warning serious as there is no way to recover or later Find the affected images 2 3 12 Export selected Each workflow ends in this panel the export of your z export selected developed images You can export either to a file on eer disk or to various on line storage places Tip you can file on dish use ctrl e from within darkroom mode to export FILE FOLDER darktable exported FiL_F O overwrite All settings of this panel can be saved for later reuse Press the B button to manage your presets 2 3 12 1 Usa
243. the mask This does not generate a confined shape but produces a linear gradient extending the whole image Click into the canvas to define the position of the line where opacity is at 50 The line has two anchor nodes which you can drag to change the rotation of the gradient Scrolling close to the center line changes the steepness of the gradient Dotted lines indi cate the distance beyond which the opacity is 100 and 0 respectively Between these dotted lines the opacity changes linearly The gradient is best seen and modified when the mask is displayed by pressing the button 49 Depending on the module and the underlying image using a gradient shape might pro voke banding artifacts You should consider to activate the dithering module see Sec tion 3 4 4 11 Dithering A gradient with controls and activated mask display drawn mask The number of shapes that are used in the current mask is displayed in the drawn mask Field Clicking on that field opens a dropdown box with all shapes that have already been defined in the context of the current image but are not yet used in the current mask You can click on any of these items in order to add it to the current mask The list also contains shapes once generated but no longer in use This way you can even get back a deleted shape A polarity button and B respectively allows the user to toggle between the normal and the inverted state of the drawn mask i e the
244. the settings colors get confined to one of the of fered RGB gamuts In effect black pixel artifacts are prevented at the costs of losing some color dynamics See Section 3 4 3 10 Input color profile For an example 3 3 Darkroom panels This section contains documentation for panels that are specific to the darkroom view 3 3 1 Navigation On the top left hand side the navigation panel dis plays a Full preview of your image with a rectangle showing the currently visible zoom area in the central panel Drag the rectangle around to pan the zoomed in view The current zoom scale is displayed to the right of the preview image Click on that figure For a quick access to some common zoom levels 3 3 2 Snapshots You can take snapshots of images as you process them A snapshot is stored as a bitmap of the current center view and is kept as long as you stay in the dark room Asnapshot can then be selected and overlayed in the current center view to help you with a side by side comparison left snapshot right active when you are tuning parameters of a module This can also be combined with history see Section 3 3 3 Histo ry stack to compare the snapshot against different stages of development You can control the split view by moving the splitline back and Forth IF you hover with the mouse over the splitline a small rotation icon will appear on the center of the line Click it to change between vertical and horizont
245. the total amount of system memory there is another limiting Factor the available address space of your hardware architecture How much memory can be addressed by a process depends on the number of address bits your CPU offers For a CPU with 32 bit address registers this is 2 32 bytes which makes a total of 4GB This is the absolute upper limit of memory that can be used by a process and it constitutes a tight situation for darktable as we have seen above darktable s escape route is called tiling Instead of processing an image in one big chunk we split the image into smaller parts for every processing step module This will still re quire one Fullinput and output buffer but intermediate buffers can be made small enough to have everything fit into the hardware limits 9 1 3 Memory Fragmentation 216 Unfortunately this is not the Full story yet There is an effect called memory fragmenta tion which can and will hit software that needs to do extensive memory management IF such a program allocates 5 times 300MB at a time and frees it again that memory should normally be available for one big 1 5GB allocation afterwards This however is often not the case The system s memory allocator may no longer see this area as one contiguous 1 5GB block but as a row of 300MB areas If there is no other free area of 1 5GB available the allocation would fail During a program run this mechanism will take away more and more of the larger memory blo
246. three methods for highlight recontruction Clip highlights analyses each pixel having at least one channel clipped Then it sets all channels to the minimum value found among the channels Effectively this converts all clipped highlights to neutral grey tones This method is most useful in cases where clipped highlights occur in non colored areas like clouds in the sky Reconstruct in LCh analyses each pixel having at least one channel clipped and trans Forms the information in LCh color space to linearly mix the channels This method is not able to reconstruct any color information the reconstructed highlights will all be neutral grey This works Fairly well with a high contrast base curve such as most manufacturers apply to their jpg which renders highlights desaturated This method is a good option on naturally desaturated things such as clouds Reconstruct color uses an algorithm that transfers color information from the unclipped surroundings into the clipped highlights This method works very well on areas with ho mogeneous colors and is especially useful on skin tones with smoothly fading highlights It Fails in certain cases where it produces maze like artifacts at highlights behind high con trast edges such as fine well exposed structures in Front of overexposed background for instance ship masts or Flags in front of the blown out sky Tip for highlight reconstruction to be effective you need to apply a negati
247. tion h mix select by blend Usage The horizontal axis represents the range of values you can work on The vertical axis shows the modifications you can apply by designing a curve For both horizontal and vertical axes you can work on lightness saturation or hue You can click on any of the eight nodes on the curve and drag to adjust it vertically A circle indicates how strong adjacent nodes will be affected Use the scroll wheel of your mouse to change the circle diameter You can also use the eight controlpoints triangles which define the vertical value of the nodes at the bottom to adjust the curve A color picker is activated by pressing kf and will show the picked values in the diagram tabbed controls You can define curves for each of the three channels lightness saturation and hue individually select by Defines the horizontal axis i e the range of values you work on You can chose between n u lightness saturation and hue default Changing this parameter resets any defined curve to a straight horizontal line mix Use this parameter to tune the strength of the overall effect 3 4 3 8 Color balance 86 Overview Usage lift This module offers a versatile tool For adjusting an color balance Y image s color balance m gamma gain factor j 0 000 red A 0 000 green 0 000 blue 0 000 3 blend off Y For each of the three primary colors red gr
248. to the pupils we have to apply two masks 3 5 4 2 Masking 1 Enable the channel mixer module see Sec j O channel mixer Y tion 3 4 3 2 Channel mixer ti 2 Activate blending Modules with blending support exhibit an addi tional combobox blend at the bottom of their GUI Blending is activated with this combobox Set value to drawn mask Additional controls are dis played which allow you to draw a mask 3 Masking the pupil Clicking the El symbol adds a circle shape Click into the canvas to place the circle Left click and drag the circle to the position of the first pupil Use the scroll wheel of your mouse while in the cir cle to change the diameter Scroll within the circle border to minimize the width of the gradual decay Alternatively you can us an elliptical shape See Section 3 2 7 Drawn mask for Further details 4 Repeat step 3 Clicking the BA symbol adds another circle shape Mark the second pupil 3 5 4 3 Desaturation 1 Approach Modifying the output channel red TET a Set output channel destination to red de red green fault Gida blend b Set red color value to 0 00 120 c Set green color value to 0 50 d Set blue color value to 0 50 You are free to experiment what gives you the most realistic pupil but this is a good starting point Another proposal is 0 10 0 60 0 30 The sum of the three values should be 1 Approach
249. ts of the image except of the remaining narrow range A range de select Function per default deselects the whole range of values giving an all zero mask as a starting point Moving the sliders inwards gradually extends the mask more and more except of the remaining narrow range For more information on the polarity Feature read Section 3 2 9 Combining drawn and parametric masks Control buttons Control buttons help you when designing a parametric mask With the color picker button Myou can select a probe from your image The corresponding values For the real and virtual data channels are then displayed within each color channel slider With the invert button you can toggle the polarities of all channels including a poten tially activated drawn mask and change the method how channels are combined into the Final mask More on that topic can be found in Section 3 2 9 Combining drawn and para metric masks With the reset button Byou can put all settings back to their default state 3 2 8 3 Examples Colorkey effect 52 To create a colorkey effect with this poppy blos som in red and the remainder of the image in mono chrome we could apply module monochrome to all parts of the image except for of the saturated red petals We choose the hue channel to control our mask as hue provides good separation between the petals and background These settings in hue channel construct a parametric blend mask t
250. ts the exposure module s parameters to their defaults 3 3 7 Module groups The module groups button bar gives you quick access Oo to darktable s processing modules splittoning lt G h vignetting lt G iu output color profile lt highpass sharpen zone system monochrome equalizer shadows and highlights DE EE SE SiE So Ei m denoise non local means crop and rotate G ih input color profile G i G w exposure demosaic G iu highlight reconstruction lt 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 white balance Here follows a description of the module groups available Active ES Favorites Basic Tone Color Correction Effect Modules you have activated and are using on the cur rent image Modules you have marked as Favorites using more modules see Section 3 3 8 More modules Modules that are frequently used such as exposure temperature etc see Section 3 4 1 Basic group Modules for working with the image s tonal values e g levels tonemap etc see Section 3 4 2 Tone group Modules for processing colors such as color correc tion vibrance etc see Section 3 4 3 Color group Modules making corrections to the image e g de noise CA correction etc see Section 3 4 4 Correc tion group Modules with a more artistic output such as vi
251. ttributes e write types dt_lua_image_t exif_exposure number The exposure time of the image Attributes e write types dt_lua_image_t exif_Ffocal_length number The focal length of the image Attributes e write types dt_lua_image_t exif_iso number The iso used on the image Attributes e write types dt_lua_image_t exif_datetime_taken string The date and time of the image Attributes e write types dt_lua_image_t exif_Ffocus_distance number The distance of the subject Attributes e write types dt_lua_image_t exif_crop number The exif crop data Attributes e write types dt_lua_image_t latitude GPS latitude data of the image nil if not set Attributes e write types dt_lua_image_t longitude GPS longitude data of the image nil if not set Attributes e write types dt_lua_image_t is_raw boolean True if the image is a RAW file types dt_lua_image_Lt is_ldr boolean True if the image is a ldr image types dt_lua_image_t is_hdr boolean True if the image is a hdr image types dt_lua_image_t width number The width of the image types dt_lua_image_t height number The height of the image types dt_lua_image_t rating number The rating of the image 1 For rejected Attributes e write types dt_lua_image_t red boolean True if the image has the corresponding colorlabel Attributes e write types dt_lua_image_t blue see types dt_lua_image_t red types dt_lua_image_t green see types dt_lua_
252. uality extra data table An empty Lua table to take extra data This table is common to the initialize store and Finalize calls in an export serie Finalize function storage types dt_imageio_module_storage_t image_table table extra_data table This Function is called once all images are processed and all store calls are Finished 162 storage types dt_imageio_module_storage_t The storage object used for the export image_table table A table keyed by the exported image objects and valued with the corresponding temporary export Filename extra_data table An empty Lua table to store extra data This table is common to all calls to store and the call to Finalize in a given export series supported Funct Von storage types dt_imageio_module_storage_t format types dt_imageio_module_format_t boolean A function called to check if a given image format is supported by the Lua storage this is used to build the dropdown Format list for the GUI Note that the parameters in the format are the ones currently set in the GUI the user might change them before export storage types dt_imageio_module_storage_t The storage object tested Format types dt_imageio_module_format_t The format object to report about return boolean True if the corresponding format is supported initialize EWC E Lon storage types dt_imageio_module_storage_t format types dt_imageio_module_format_t images table o
253. ualizer cloning 96 collect images 24 collections 16 24 color balance 87 color contrast 84 color correction 85 color labels 17 color management 54 display profile 84 gamut check 84 input color profile 88 output color profile 83 softproof 84 unbreak input profile 89 color mapping 112 color picker 58 color spaces 55 color zones 86 colorize 112 comboboxes 41 command line parameters 3 conditional blending 50 contrast 71 see also levels see also tone curve copy images 27 create images 28 crop and rotate 65 cropping an image 65 D darkroom 37 darkroom panels 57 bottom panel 63 color picker 58 Filmstrip 64 histogram 61 history stack 57 mask manager 59 module groups 61 more modules 62 navigation 57 overexposed warning 63 snapshots 57 underexposed warning 63 darktable vii darktable cli 4 defringe 100 delete images 27 demosaic 71 denoise bilateral 93 equalizer 90 non local means 93 profiled 92 raw 97 display profile 84 dithering 97 E ellipse 48 equalizer 90 EXIF data 26 export 33 exposure 69 F file export 33 file import 22 fill light 74 film rolls 16 filmstrip 7 filtering 18 focus detection 14 framing 102 G gamut clipping 56 88 229 geo tagging 30 global tonemap 80 GPU computing 219 gradient 49 graduated density 114 grain 107 group images 18 28 H HDR images 24 27 highlig
254. uld be set to 16 In case you are migrating From a 32 bit to a 64 bit system you will need to check these settings and manually change them if needed in darktable s preference dialog Typically there is no need to restrict oneself in the number of background threads on a 64 bit system On a multi processor system a number of two to eight threads can speed up thumbnail generation considerably versus only one thread The reason is not so much taking maximum advantage of all your CPU cores darktable s pixelpipe anyhow uses all of them in parallel but hiding I O latency One exception is worth to be mentioned IF you use darktable to process stitched panora mas e g TIFFs as generated by Hugin these images can reach considerable sizes Each background thread needs to allocate enough memory to keep one full image plus inter mediates and output in its buffers This may quickly run even a well equipped 64 bit sys tem out of memory In that case lower the number of background threads to only one 9 2 darktable and OpenCL darktable can use GPU acceleration via OpenCL to improve performance 9 2 1 The background Processing high resolution images is a demanding task needing a modern computer Both in terms of memory requirements and in terms of CPU power getting the best out of a typical 15 20 or 25 Megapixel image can quickly bring your computer to its limits darktable s requirements are no exception Our decision to not compromise p
255. ule_t expandable boolean True if the lib can be expanded retracted types dt_lib_module_t expanded boolean True if the lib is expanded Attributes e write types dt_lib_module_t reset self function A Function to reset the lib to its default values This Function will do nothing if the lib is not visible or can t be reset self types dt_lib module t The lib to reset types dt_lib_module_t on_screen boolean True if the lib is currently visible on the screen 8 2 2 25 types dt_view_t 205 dt_type A darktable view types dt_view_L id string A unique string identifying the view types dt_view_t name string The name of the view 8 2 2 26 types dt_lua_backgroundjob_t dt_type A lua managed entry in the backgroundjob lib types dt_lua_backgroundjob_t percent number The value of the progress bar between 0 and 1 will return nil if there is no progress bar will raise an error if read or written on an invalid job Attributes e write types dt_lua_backgroundjob_t valid boolean True if the job is displayed set it to False to destroy the entry An invalid job cannot be made valid again Attributes e write 8 2 2 27 types dt_lua_snapshot_t dt_type The description of a snapshot in the snapshot lib Attributes e has_tostring types dt_lua_snapshot_t filename string The filename of an image containing the snapshot types dt_lua_snapshot_t select SeListrunce vont 206 Activates this snapshot on the display
256. und in order to minimize latencies IF you still ex perience long delays when switching between images or if you intend to quickly advance in your collection consider to disable the option do high quality processing For slideshow which gives a much higher processing speed at the expense of a possible slight loss in quality see Section 7 1 GUI options 135 136 Chapter 7 Preferences and settings darktable comes with a number of settings that can be configured by users You reach the configuration menu by clicking E at the top of the screen Su darktable preferences O x GUI options core options ses shortcuts presets width of the side panels in pixels dont use embedded preview JPEG but half size raw ask before removing images from database ask before erasing images from dish ask before moving images from film roll folder ask before copying images to new film roll folder number of folder levels to show in lists ignore JPEG images when importing film rolls recursive directory traversal when importing filmrolls creator to be applied when importing publisher to be applied when importing rights to be applied when importing comma separated tags to be applied when importing initial import rating enable filmstrip maximum width of image drawing area 1798 maximum height of image drawing area 1190 compression of thumbnail images high quality slow 137 7 1 GUI options These options contr
257. ur database In case darktable wants to create a thumbnail but is not able to open the input file a skull is displayed instead Users are advised to remove images from the database see Section 2 3 6 Selected image s before physically removing them from disk Alternatively you may occasionally run the script purge_non_existing_images sh from darktable s toolset to clean up your database Another possible cause is sometimes darktable encounters an input image having an ex tension that seems valid for darktable but which has a File Format that darktable does not support yet darktable tries to process the image but is not able to get the job done The third possible cause for getting skulls is memory shortage IF darktable runs out of memory while generating a thumbnail it will warn you and display a skull this can happen if darktable is run with suboptimal settings on a 32 bit system Please consult Section 9 1 darktable and memory for more information 2 2 4 Star ratings and color labels Star ratings and color labels help you to sort and rank images according to your own cri teria An image s star rating and its color labels are displayed in the thumbnail You can give a rating from zero to Five stars to an image The quality criteria which lead to a rating are Fully up to you Whenever you import images each image receives a default rating which you can define in GUI options see Section 7 1 GUI options You can later
258. ur mouse will allow navigation in the map Left click will drag the map using the scroll wheel will zoom in or out There are on screen controls and displays that assist you to find your way A navigation area is located on top left of the map Use it as an alternative to mouse dragging and scrolling The scale of your map is displayed on bottom left On bottom right you see the geographical coordinates for the center of the map Images that already have geo location attributes in their metadata are displayed as small icons on the map In order to assign geo coordinates to an image activate the Film strip on the lower panel press Ctrl f You can simply assign a geo location to an image by dragging the image icon From the Film strip and position it onto the map darktable will record the new geo location longitude and latitude as part of the image metadata Exported images will include this data In order to remove geo coordinates from an image just drag it from the map and drop it onto the Filmstrip Left and right to the central map there are panels for additional control 5 2 Map panels This section contains documentation for panels that are specific to the map view 5 2 1 Left panels The panels on the left side we already know from gt collectimages lighttable mode Section 2 3 Lighttable panels gt recently used collections gt image information Choose your image selection rules with the collect im ages p
259. use wheel to zoom in and out Moving the mouse while pressing the left mouse button allows you to navigate through your collection In filemanager view you can can change the num ber of images in each row using the slider next to the Filemanager option or by using ctrl mouse wheel Use your mouse wheel to navigate through your collection While in Filemanager mode you can scroll not select up and down through your collection using T _ In zoomable lighttable _ _ 7 J allow you to move left right up down through your collection Pressing g goes to the top shift g to the bottom To locate where you are in a collection there are indicators at the extreme borders of the window left right For your position when you are in Filemanager mode left right and top bottom for your vertical and your horizontal position respectively when you are in the zoomable lighttable view While holding down the zkey a Fully zoomed preview of the image under the mouse cursor is displayed You can use this Feature For a quick inspection of image quality while rating and selecting images Holding down the ctlr z key Fully zooms into the image and additionally activates an analy sis For Focus regions Areas of high sharpness are indicated by a red border the higher the color intensity the better the sharpness In case that no area of high sharpness is de tected darktable indicates areas of moderate sharpness with a blue border For this tool to work
260. ut profile Sets the color profile for output export causing darktable to render colors with this pro File darktable embeds the profile data into the output file if supported by the File Format this allows other applications reading the file to correctly interpret its colors Some file formats namely PNG do not support embedded profiles by their specifica tion However there is an established de facto standard to embed profiles which dark 83 table adheres to Beware that some applications might fail to correctly handle those pro Files and render colors incorrectly As not all applications e g image viewers are aware of color profiles a general recom mendation is to stick to sRGB as the default output profile You should only deviate from SRGB if this is really required and if you know what you are doing softproof profile Sets the color profile for softproofing softproof allows you to preview your image rendered using a printer profile so as to see how colors will end up on the Final print and is toggled on and off by pressing ctrl s Likewise gamut check is toggled on and off by pressing ctrl g this Function highlights in cyan all pixels out of gamut with respect to the selected softproof profile softproof and gamut check are mutually exclusive modes that can be activated at any place in darkroom mode and when this module is in Focus the status is displayed below the image Tip at other times it may not be ob
261. utes the group head while in an expanded view of a group clicking on the G symbol of the desired image IF you collapse an image group and then enter darkroom mode e g by double clicking on the thumbnail the group head will be opened for developing Image groups are a convenient way to protect an existing history stack against uninten tional changes Suppose you have just finalized an image and want to protect its current version all you need to do is select the image click duplicate in the selected images panel and make sure that grouping is switched on and that the group is collapsed Now whenever you open the image group again in darkroom only the group head will be al tered The underlying duplicate remains unchanged Please note that duplicating images here only generates a copy of your history stack stored in another small XMP file There is still only one RAW file so you don t waste a lot of disk space 2 2 7 Sidecar files darktable is a non destructive image editor This means that darktable opens images read only Any newly added metadata tags and parameters of image operations the history stack are stored in separate xmp files so called sidecars allowing you to store informa tion about the images as well as the Full editing history without touching the original RAW Files When you import an image into darktable For the First time an XMP file with default settings is generated automatical
262. values Structural details in Fully blown out highlights by nature of the digital sensor can not be recovered Howev er you can correct unfavorable color casts in these areas with the highlight reconstruction module 1 3 2 8 Adjusting tonal values Almost every workflow is likely to include adjusting the image s tonal range darktable offers several alternative modules to take care of that The most basic one is the contrast brightness saturation module In the tone curve module tonal values are adjusted by con 9 structing a gradient curve The levels module offers a concise interface with three mark ers in a histogram In addition there is a zone system module which allows control over tonal values by zones inspired by the work of Ansel Adams 1 3 2 9 Enhancing local contrast Local contrast enhancement can emphasize detail and clarity in your image Carefully used it can give your photograph the right pop darktable offers several modules for this task The local contrast module is easy to handle with just a Few parameters A much more versatile but also more complex technique is offered by the equalizer module Have a look at its presets to get a Feeling For how it works Equalizer is darktable s Swiss Army Knife For many adjustments where spatial dimension plays a role 1 3 2 10 Color adjustments darktable offers many modules for adjusting colors in an image A very straightforward technique is implemented in the co
263. ve EV correction in the exposure module see Section 3 4 1 5 Exposure IF you want to avoid a general darkening of your image you can use darktable s mask feature in that module to limit the EV correction to only the highlights see Section 3 2 7 Drawn mask and Section 3 2 8 Parametric mask method Choose the method for highlight reconstruction clipping threshold Manually adjust the clipping threshold against magenta highlights The default is usually satisfactory without any need for additional adjustments 3 4 1 9 White balance Overview This module is used to set the white balance You 0 white balance Y have three ways to interact with it a Set up tint and tt 1001 temperature b define the value of each channel or an te c choose from predefined white balances green 1 000 blue 1 000 preset camera white balance Y Usage tint Alter the colour tint of the image from magenta value lt 1 to green value gt 1 The chan nel sliders will be updated when you adjust this parameter temperature Set the color temperature in Kelvin The channel sliders will be updated when you adjust this parameter darktable derives the color temperature from the EXIF data using some model assumptions The value given is not meant to be authoritative In the end only the updated channel values determine how the image is modified 73 red green and blue channels Set the channel values on a scale fro
264. ve a look at the tone curve module see Section 3 4 2 3 Tone curve and the levels module see Section 3 4 2 2 Levels which can produce similar results with less side effects as they come later in pixelpipe Defines the mode of operation Currently darktable only supports manual operation Future versions of darktable will additionally allow automatic exposure correction Adjust the black level exposure auto Adjust the exposure correction EV Activating this checkbox makes darktable calculate a correct exposure for the rectangular view appearing in the centre of the image You can draw your own selection using your mouse An adjustment slider to the right of the auto exposure checkbox lets you define what percentage of bright values are to be clipped out in the calculation 3 4 1 6 Contrast Brightness Saturation 70 Overview This module offers a very basic tool for adjusting an 6 contrast lightness saturation Y image s contrast brightness and saturation contrast 0 00 lightness 0 00 a saturation 0 00 blend off Y Usage The module has sliders for each of the three affected attributes In their neutral position zero the image remains unchanged Shifting sliders left to negative values reduces con trast brightness and saturation respectively Shifting right to positive values leads to an increase Much more versatility for contrast and brightness adjustment is offered by the tone
265. veral reasons why darktable works in the way described e The sequence of modules has been selected with great care in order go give highest output quality Changes to the sequence would generally worsen the result rather than improving it e Certain image processing steps just don t make sense if they are shifted in the pixelpipe To mention just a few highlight reconstruction needs to be done on raw data before demosaicing and the demosaic step needs to be performed before any input color pro File can be applied e Most of darktable s modules are designed to work within a specific color model see Sec tion 3 2 10 Color management for more details Full Flexibility would require mod ules to support different parallel algorithms depending on the color space they are working in this would drastically increase complexity That said the fixed sequence of modules is not likely to change in the near future Whenever you activate or deactivate a module or go back to a module and change the parameters this adds an item on top of the history stack For example when working on a raw file the history stack on the left panel might say that you First enabled bilateral filtering then disabled base curve then adjusted white balance But at any time the processing took the RAW image adjusted white balance on it then demosaic then base curve if enabled then bilateral filtering if enabled as shown bottom to top on the right
266. vided by the API that contains all images in the database currently visible or not duplicate or not Each entry in the database is an image object Image objects are complex objects that allow you to manipulate your image in various ways it is all documented in Section 8 2 2 1 types dt_lua_image_t To display our images we use darktble debug dump which is a Function that will take anything as its parameter and recursively dump its content Since images are complex objects that indirectly reference other complex objects the resulting output is huge Below is a cut down example of the output toplevel userdata dt_lua_image_t images 100 JPG publisher string f n path string images move function exif_aperture number 2 7999999523163 PLOncSs SG ELO g TI make_group_leader function exif_crop number 0 duplicate_index number 0 is_raw boolean false exif_iso number 200 is_ldr boolean true rating number 1 desecrapcion String 9 Th red boolean false get_tags function duplicate furetion Creator String 5 T latitude nil blue boolean false exif_datetime_taken string 2014 04 27 14 10 27 exif_maker string Panasonic drop_cache function Crei e 9C rING we ee reset function create_style function apply_style function film userdata dt_lua_film_t images 1 userdata dt_lua_image_t toplevel exif_exposure number 0 0062500000931323 e
267. view This module is able to correct certain lens Flaws 0 lens correction namely distortions transversal chromatic aberra Canon EOS 5D Mark Ii tions TCA and vignetting It relies on the external Canon Canon EF 50mm t 1 2L USM 4 mm 50 vT tl TAE 00 library lensFun which comes with correction profiles ay cee ee For many but not all common cameras end lenses geometry rectilinear Y scale 0 995 mode TCA red TCA blue corrections done only distortion Usage 94 In order to perform lens corrections the module uses EXIF data of your image to identify the specific camera lens combination and collects the needed correction parameters from a profile in lensfun s database camera lens The camera make and model as determined by EXIF data You can override this manually and select your camera from a hierarchical menu The lens make and model as determined by EXIF data You can override this manually and select your lens from a hierarchical menu This is mainly needed for pure mechanical lens es photometric parameters focal length aperture focal distance Corrections additionally depend on certain photometric parameters that are read from EXIF data focal length needed for distortion TCA vignetting aperture needed for TCA vignetting and focal distance needed for vignetting Many cameras do not record focal distance in their EXIF data most likely you need to set this manually You can manually
268. vious if the softproof mode is still active or not IF in doubt press ctrl g which will switch to gamut check and be clearly distinguishable by cyan marked pixels Press ctrl g again and you are back to normal display mode display profile Sets the color profile for the display The additional option system display profile is the preferred setting when working with a calibrated display the profile is taken either From your system s color manager or from your X display server In gui options see Section 7 1 GUI options you can specify which method to use 3 4 3 4 Color contrast Overview Usage The color contrast module provides simplified con TEI color contrast Y trol For changing the contrast or separation of colors green vs magenta 1 00 between either green magenta or blue yellow axis blue vs yellow 1 00 blend off Y Higher values increase color contrast lower values decrease it The effect of this module s sliders are similar to applying a steepened or Flattened a or b curve in module tone curve see Section 3 4 2 3 Tone curve green vs magenta Changes color contrast for green versus magenta blue vs yellow Changes color contrast for blue versus yellow 3 4 3 5 Color correction 84 Overview This module can be used to modify the global satura tion give a tint to the image or to split tone it saturation blend Usage color board For split toning drag the white dot
269. with different algorithms called blending operators or blend modes Each blend mode is further controlled by a parameter called opacity which can have a value between 0 and 100 and defines how input and output image contribute to the Final result Typically an opacity value of 0 gives as a result an image that is identical to the input image the module remains without effect An opacity value of 100 delivers the maximum effect of the module with the blend mode chosen The opacity value can be the same for all image pixels In this case blending acts uniformily on the image Alternatively you can make opacity values to vary between different image locations or pixel values This is called a mask and gives fine control over what parts of an image are affected by a module and to what extent At your choice you may activate a drawn mask or a parametric mask or a combination of both 3 2 5 2 Usage Modules with blending support exhibit an additional blend P combobox blend at the bottom of their GUI PEATE normal 7 opacity 100 43 blend Blending is activated with this combobox Depending on the value selected additional con trol elements will show up off module s output is passed to the next module in pixelpipe without additional reprocess ing No Further controls are displayed uniformily reprocessing takes place with the chosen blend mode and opacity value the same for all pixels Additional controls to sele
270. xif_lens string 153 detach_tag function toplevel film 2 detach_tag exif_focal_length number 4 5 get_group_members function toplevel film 2 get_group_members id number 1 group with function toplevel film 2 gqroup with delete function toplevel film 2 delete purple boolean false is _hdr boolean false exif_model string DMC FZ200 green boolean false yellow boolean false longitude nil filename string 100 JPG width number 945 attach tag fumecr iron voplevel fidmZ2 ateach tac exif focus distance number O height number 648 local_copy boolean false Copy Lunction gt toplevel fitm 2 copy group_leader userdata dt_lua_image_t toplevel As we can see an image has a large number of fields which provide all sort of infor mation about it We are interested in the red label documented in the section called types dt_lua_image_t red This field is a boolean and the documentation tells us that it can be written We now just need to find all images with that field and print them out darktable require darktable for _ v in ipairs darktable database do if v red then PLIMEICOSEriIng v end end This code should be quite simple to understand at this point but it contains a Few inter esting aspects about lua that are worth highlighting e ipairs is a standard lua Function that will iterate through all numeric indices of a ta ble We use
271. y a Factor of 2 to 3 NVIDIA devices and drivers seem to have a more efficient memory transfer technique even For arbitrary memory regions As they may not show any performance gain and even may produce garbled output opencl_use_pinned_ memory should be left at its default FALSE for those devices 9 2 8 Multiple OpenCL devices While most systems will only have one OpenCL capable GPU installed darktable is also able to make use of multiple devices in parallel There is a configuration parameter which helps to optimize GPU priorities in that case It is important to understand how darktable uses OpenCL devices Each processing se quence of an image to convert an input to the final output using a certain history stack is run in a so called pixelpipe There are four different types of pixelpipe in darktable One type is responsible to process the center image view or Full view in darkroom mode an other pixelpipe processes the preview image navigation window top left in darkroom mode Of each of these two pixelpipe there can be one at a time with the Full and the preview pixelpipe running in parallel In addition there can be multiple parallel pixelpipes doing File exports and there can be multiple parallel pixelpipes generating thumbnails IF an OpenCL device is available darktable dynamically allocates it to one specific pixelpipe For one run and releases it afterwards The computational demand depends a lot on the pixelpipe type Pr
272. y gt t Return lt Primary gt g lt Primary gt s bracketleft bracketright 147 7 5 Presets This menu gives you an overview of the presets that are defined For darktable s modules In this dialog you can select whether a certain user defined preset shall be auto applied to matching images darktable already comes with a set of pre defined presets for several modules In addi tion you can define your own presets From within each module in darkroom mode see Section 3 2 3 Module presets Pre defined presets are shown with a lock symbol Their auto apply properties can not be changed Double clicking on a user defined preset will open a menu aperture 0 Ti focal length D 1000 auto apply this preset to matching images activate this checkbutton to automatically apply the preset on newly imported images a set of fields is displayed where you can define patterns to be matched against EXIF data only show this preset for matching images model maker lens iso 148 activate this checkbutton to hide the preset in darkroom mode if it does not match the defined patterns a pattern to be matched against the EXIF field that describes your camera model use as wildcard a pattern to be matched against the EXIF Field that describes the maker of your camera use as wildcard a pattern to be matched against the EXIF field that describes your lens use as wild card only apply the preset
273. y significantly There are dif ferent manufacturers and even different generations of GPUs from the same manufac turer may differ At the same time GPU manufacturers don t normally disclose all hardware details of their products to the public One of the known consequences is the need to use proprietary drivers under Linux if you want to take Full advantage of your graphics card Fortunately an industry consortium lead by The Khronos Group has developed an open standardized interface called OpenCL It allows the use of your GPU as a numerical pro cessing device OpenCL offers a C99 like programming language with a strong focus on parallel computing An application that wants to use OpenCL will need OpenCL source code that it hands over to a hardware specific OpenCL compiler at run time This way the application can use OpenCL on different GPU architectures even at the same time All hardware secrets are hidden in this compiler and are normally not visible to the user or the application The compiled OpenCL code is loaded onto your GPU and with certain API calls it is ready to do calculations for you 9 2 3 How to activate OpenCL in darktable Using OpenCL in darktable requires that your PC is equipped with a suitable graphics card and that it has the required libraries in place Namely modern graphics cards from NVIDIA and ATI come with Full OpenCL support The OpenCL compiler is normally shipped as part of the proprietary graph
274. you migrate to darktable It is very important to understand that this import process will never give identical results The underlying development engines are very different from application to application and additionally depend a lot on the specific image In some cases it will probably be close and in some cases the development will need manual adjustment in darktable The migration happens automatically when entering the darkroom view provided that a corresponding XMP sidecar is found At present darktable is able to deal with the Following development steps from Light room generated XMP files with the corresponding darktable module in parentheses e crop and rotate crop and rotate e black level exposure e exposure exposure e vignette vignette e clarity local contrast e tone curve tone curve e HSL color zones e split toning split toning e grain grain e spot removal spot removal 2 2 9 Local copies Many users have huge image collections which they store on extra hard drives in their desktop computer or on an external storage medium like a RAID NAS etc So it is a com mon use case to develop some images while travelling using a notebook and then later synchronize them to the original storage medium But copying images manually from the main storage to the notebook and back is cumbersome and prone to errors The local copies Feature of darktable has been designed to directly support those use
275. ypes dt_imageio_module_format_data_j2k bpp number The bpp parameter to use when exporting Attributes e write types dt_imageio_module_format_data_j2k format types dt_imageio_42k_format_t The Format to use 198 Attributes e write types dt_imageio_module_format_data_j2k preset types dt_imageio_j2k_preset_t The preset to use Attributes e write 8 2 2 12 types dt_imageio_module_storage_t dt_type A virtual type representing all storage types types dt_imageio_module_storage_t plugin_name string A unique name for the plugin Attributes e write types dt_imageio_module_storage_t name string A human readable name for the plugin Attributes e write types dt_imageio_module_storage_t width number The currently selected width for the plugin Attributes e write types dt_imageio_module_storage_t height number The currently selected height for the plugin Attributes e write types dt_imageio_module_storage_t recommended_width number The recommended width For the plugin Attributes e write types dt_imageio_module_storage_t recommended_height 199 number The recommended height for the plugin Attributes e write types dt_imageio_module_storage_t supports_format Sselitruncte ron format types dt_imageio_module_format_t boolean Checks if a Format is supported by this storage self types dt_imageio_module_storage_t The storage type to check against Format types dt_imageio_module_format_t The for
276. ypes dt_lib_ module _t darktable gui libs module_toolbox The tools on the bottom line of the UI overexposure Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs session The session UI when tethering Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs histogram The histogram widget Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs export The export menu Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs history The history manipulation menu Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs colorpicker The colorpicker menu Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs navigation The Full image preview to allow navigation Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs masks 174 The masks window Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs view_toolbox Attributes e has_tostring e parent types dt_ lib module _t darktable gui libs live_view The liveview window Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs map_settings The map setting window Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs camera The camera selection UI Attributes e has_tostring e parent types dt_lib_ module _t darktable gui libs location The lo

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