User´s Guide Ugra Display Analyzis and Certification Tool
Contents
1. Uniformity Check ugra O measurement Simply follow the instructions on the screen to prepare for the analyzing procedures 1 6 Calibration analysis Now select the Calibration Check button and start the measurements UDACT will then measure the patches for the graybalance the profile quality and the media wedge The actually measured patches will be displayed on the left side as RGB Lab and XYZ values The measurements includes the 21 patches for the gray balance the 35 patches for the profile quality and the 48 patches of the ugra fogra MediaWedge e The measurement last around 10 minutes depending on the measurement device s speed 1 7 Uniformity Check optional Select the Uniformity button follow the instructions and measure the 9 patches on the screen according to the ISO 12646 draft Minimum Requirements for Softproofing Displays This draft defines a maximum deviation from the center to one of the 8 other other areas This uniformity analysis is not taken into account for the judgement of the calibration as there are only a few displays that will match the ISO 12646 specifications However it can be used for reference Deviations of less than 15 indicate an acceptable display 1 8 Summary Press the Summary button and UDACT displays a summary telling whether the three criteria have been passed or not Additionally UDACT recommends the analysed screen for the most common printing envi2. Which printing technology can be reproduced on the screen A good answer to these questions could be an ISO regulation Fortunately the upcoming ISO 12646 revision will help to get things sorted but this new regulation is not intended for a desktop certification It s aimed for laboratories to testify the compliance with the minimum specifications for soft proofing displays The regulation does not enable users to certify their individual display but gives some guidelines for testing and certification and it defines minimum requirements only The aim of ugra Display Analysis and Certification Tool is to implement a foundation for the objective quality oriented and compareable evaluation for an individual soft proofing display In addition to the certification process a recommendation for a specific printing Display Analysis and Certification Tool DeltaE C L ab DeltaE AE is the overall deviation split into AL for lightness deviation and Aab for the chromatic deviation With grays Aab equals AC chromatic What difference recognizes the human eye The averageobserver can notice the difference between two colors that are AE 5 6 apart A trained eye is capable of differentiating two colors that differ only AE 3 4 However the human eye is very sensitive to changes away from achromatic or monochromatic tones a and b values near the L Axis in this case a trained observer can often notice a difference be
3. and a tool that is made for desktop certification Differences in the specifications will most likely occur and have to be accepted if they are tighter than the regulation and help to keep the main goal of the certification approach Additionally the upcoming regulation will most likely only be valid for new product series Exsisting displays will not be certified due to cost concerns In contrast the UDACT is explicitely developed to certify and Display Analysis and Certification Tool A 75 NTSC 2 display offers a quite good coverage of ISOcoated 1 The display s 100 NTSC 4 does not match the real NTSC 3 and Adobe RGB 2 does not even cover ISO cated 1 completely analyze all kind of soft proofing displays It doesnt matter if this a 3 year old CRT ora brand new TFT Of course older units may not match the highest level and cannot be compared 2 2 Alternative Certifications In north america the SWOP certification does also cover displays Unfortunately this certification is always performed with the combination of a display and a second product most likely a remote proof application The certification is only valid if both parts are present and has to be reissued every 24 month Additionally a SWOP certification is a laboratory based analysis of a product series It does not tell anything about the individual monitor 2 3 Technological basics A gamut size based certification does not
4. application professionals From the first idea and the final release the past 24 months were filled with extensive research and the vision to create a working standard for the display certification worldwide The development team would like to thank everyone for the committment and help for this project St Gallen Switzerland May 2006 Display Analysis and Certification Tool amp The reliability of every digital and analogue tool highly depends on the ability to finally trace and judge the results The orange is always the same but due to the sur rounding colors it looks different The same applies to the gray patch It seems to be darker or lighter depen ding on how much black is dominant Color difference 0 0 AE CIE Lab Color difference 15 1 AE CIE Lab Color Difference 15 1 AE CIE Lab The Pantone orange gets a severe color shift if it is viewied under suboptimal lighting conditions Part 1 Manual The ugra Display Analysis and Certification Tool allows to analyze evaluate and finally certify a display for soft proofing environments Prior to the proof and the certification there is something important to look at the light 1 1 Environmental Lighting Wrong or unsufficient environmental lighting is one of the most problematic issues upon comparing soft proofs contract proofs and prints The tonal response of a print always depends on the light that is used to illuminate the viewing area
5. focus on the gray balance is one results of the extensive discussions It is easy to have good primaries but that does not warrant a perfect gray balance A good gray balance meas at the end that all steps of gray should be reproduced and that there is no color shift in the grays The profile quality or profile consistancy Display Analysis and Certification Tool amp The correction of a software calibrated display left is visible in the curves and in slingly banded gradiants The hardware calibrated display right does not suffer from restrictions of the bandwith is the third main part of the UDACT certification process The precision to reproduce a specific color inside the display s gamut has to achieve a very high level One might think that inside the gamut almost every color must be reproduced without any deviation But thats not true In fact most TFT panel are non linear means their addition of red green and blue is not always the same at different luminance levels of the three channels This non linearity or non additivity can be corrected by using a LUT look up table profile profile Unfortunately the main soft proofing applications do not support LUT profiles very well Due to that a matrix or TRC profile should be used instead But a matrix cannot correct non linearities So the less optimal profile type must be used to have some common ground 2 4 Hardware vs software No displa
6. handfull of systems Therefore the specifications have to be pushed to AC 1 0 which is still hard to achieve Therefore this criteria has been set up as the average deviation of 21 grays from 0 to 100 in increments of 5 Measurements in the extreme darks result In incorrect measurements Therefore the UDACT takes only the measurements above 1 of the white luminance on into account DONNER compe The colorfull grayscale upper one shows a shift on the a Axis and the a Axis that is unacceptable in With a unit that has 120 cd m2 the UDACT comparison to the neutral reference lower one takes only measuremets above 1 2 cd m2 1 of the Luminance L into account Averaging has always the problem that it levers peaks in the deviation Especially with grays a unit can reach a good average but E some grays can be very neutral others can oso have a color shift Therefore UDACT also LI uses a chromatic deviation range to specifiy g the gray balance criteria 1 00 E 3 00 2 50 2 00 1 50 1 00 0 50 f ee Example A calibration does not meet the criteria as the maximum deviation on the blue axis b reached nearly AC 1 5 and on the red axis a more than AC 1 Booth values together result in a range of more than AC 2 5 Thats 0 5 above the maximum allowed deviation The calibration does not meet the criteria as the range and thus the unit is not certified to be soft is higher than AC 2 proofing d
7. much better coverage of the ISOcoated reference printing space Nevertheless the 2 dimensional plot shows only have the truth In 3D we can clearly notice that the display s CYAN is still AE 5 away from the reference A 75 NTSC display covers between 90 to 94 of the ISOcoated gamut while a 100 NTSC display covers up to 98 The 25 increase in gamut volume from 75 to 100 does only result ina 4 to 8 increase in real printing gamut coverage Up to date there is no display available that covers the whole ISOcoated reference A comparison between a proof like the visual print reference shows therefore even for a 75 unit a very good match But display technology is developing and there will be definetely units available that support even larger gamuts As a conclusion we can see that the gamut is not enough for the certification of a soft proofing display The gamut size roughly tells about the coverage of ISOcoated but cannot tell anything about the precision of the gray balance or the profile quality 2 3 Colorimetrical dependencies In addition to the gamut size the profile quality and the gray balance precision are the primary certification tasks In the past 20 years the printing industry shifted its focus from the gray balance to the primaries Today professionals and scientists are discussing a way to return to the gray balance focus The ECS European Color Initiative gray control strip and the UDACTs
8. Control Tools Schweizer Kompetenzzentrum f r Medien und Druckereitechnologie Centre de comp tence suisse pour la technologie des m dias et de l imprimerie Swiss Center of Competence for Media and Printing Technology Ugra Display Analyzis and Certification Tool Users Guide and technical Whitepaper Introduction The ugra Display Analysis and Certification Tool allows for the first time ever the individual and objective certification of soft proofing displays and color displays Backed up by the reputation of the Swiss Center of Competence for Media and printing Technology the UDACT is the first institional approach for the certification of soft proofing displays Apart from beeing a certification tool the UDACT defines specification to separate soft proofing displays from office displays and therefore gives users a guideline for the descision which display type fits their needs the best To give a wider overview about the technological surrounding of the display certification this manual is devided into two major parts The first part is the user manual and describes how to use the certification tool and how to judge the results The second part is the technological whitepaper that allows an in depth view on the basics of soft proofing environments and specifications of the tool The ugra Display Analysis and Certification Tool was designed and developed with the gratefull help of many scientific and
9. E The recommendations are Multicolor Highbody for the future SOcoated Gravure offset coated paper ISOuncoated offset uncoated paper SOnewspaper If a display fails in only one of the three criteria it will be downgraded to Layout use only That does not mean it s a bad monitor but is not as precise as it is necessary for soft proofing environments The ugra certified logo is displayed upon passing the test sequence If the test sequence is not passed the logo changes to not certified To judge the calibration UDACT uses a set of tresholds to separate between acceptable und unacceptable calibrations Gray balance max 1 AC average max 2 AC range Profile Quality max 3 AE average max 6 AE peak Gamut MK max 4 AE average The recommendations are based on the volume that an analyzed unit can reproduce within the allowed deviations for contract proofing To be recommended for ISOcoated or Gravure a display must have at least 90 of the gamut 1 9 Report The Report panel provides more detailed information regarding the measured values and the actual deviations The standard report encludes the summaries of all the measurements and calculations The extensive report includes all measured patches and allows an in depth view at the measured values Both reports can be saved in Plain Text format HTML or as a PDF and can used for future reference Display Analysis and Certi
10. The perception of a color highly depends on the surrounding colors and the lighting conditions Colored backgrounds and the contrast between two areas influence our idea of the color Due to that a standard mid gray background for the computer s desktop is more suited for color editing than a fruity flavoured scene Apart from this the light that iluminates the colors that are observed has an even larger influence on the perception of the color As the color appearance changes with different illuminants the IS03664 Viewing Conditions and 1S012647 X Graphic Technology define a standardized lighting for judging proofs the D50 standard 1 2 Calibration recommendations There aresome fundamental issues that have to be taken into account for a calibrated screen Whitepoint or color temperature Chromatic adaption Luminance brightness Gamma gradation Since the 1930s D50 is defined to be the standard lighting for judging color but Display Analysis and Certification Tool it is obviously unsuitable for calibrating a display D50 calibrated display seems to be much to warm compared with a D50 viewing booth or the human eye s expectation of what D50 should look like on a screen During extensive research a whitepoint or color temperature for the monitor between 5 600 k and 6 000 k or an average of 5 800 K was found to be much more suitable for the comparison betweeen proof and screen 90
11. eviation of up to AE 20 Unfortunately this deviation looks higher from the numbers as it is visually That s one of the disadvantages of deltaE 76 Example The measurement showed a gamut size of 94 and an average deviation of AE 4 2 This unit is uncertified With prints the MediaWedge can testify Display Analysis and Certification Tool the compliance to the specifications but the color reproduction might not be optimal 48 patches are not enough to judge the whole color appearance That s why UDACT is based on three individual test sequences The combination makes sure that the display s state is fully analyzed 2 8 UDACT specifications at a glance Gray balance average AC 1 range AC 2 Profile quality average AE 3 maximum AE6 Soft proof average AE 4 volume 90 If a system reaches exactly these values or less except volume 90 and above then it is certified according to the ugra DACT Any failures with the three criteria will result in a downgrade to uncalibrated and the unit is testified to be complinat with the demands of layout only workflows Display Analysis and Certification Tool amp
12. f 400 Lux To match this value the display should have a luminance of at least 120 Candela cd m2 Aside from the whitepoint and the Display Analysis and Certification Tool 0 0 5 5 10 10 15 15 20 20 25 25 30 30 35 35 40 40 45 45 50 50 55 55 60 60 65 65 70 70 75 75 80 80 85 85 90 90 95 95 100 100 Gamma 1 8 right and L center offer better details in the darks and the lights than Gamma 2 2 left luminance the gradation has to be specified In the past a gamma of 1 8 was referred to be the standard Macintosh gamma while 2 2 was the PC s gamma With ICC Colormanagement this is no longer suitable for the workflow Back in the 80 s a gamma of 1 8 was defined to match the dot gain of a standard offset press better than gamma 2 2 This is still valid and can be used for both systems Macintosh and PC The two polular D50 RGB working spaces ECI RGB and ColorMatch RGB are based on Gamma 1 8 an recommended for the use in an icc workflow The also D50 based L is an alternative to Gamma 1 8 that is more adapted to the human eye s tonal rsponse curve But one has to use a L based RGB working space like L RGB to avoid large deviations Gamma 2 2 is not suited for soft proofing because a lot of the image details in the darks and lights will be lost The gamma 2 2 and D65 6 500 K based Adobe RGB is not well suited for D50 workflows Thinking workf
13. fication Tool amp What is delta E Delta E is the result of the calculated or measured deviation between two colors The most common used one is deltaE Lab 76 The problem with this 30 year old AE version is that the numerical deviation does not match the visual deviation with deltaE 2000 for example the visual ewuals the numerical error Therefore deltaE Lab 2000 will most likely be the relacement in the long term The L a b System a Part 2 Technological Whitepaper In today s media landscape an objective certification of the calibration precision like the ugra fogra MediaWedge for contract proofing is one of the most demanded developments There is a lot of confusion on the user s side regarding the precision and and usage of soft proof displays This is also due to the different color deviation methods and specifications used in the validation routines of today s calibration software Sometimes DeltaE 76 and sometimes DeltaE 94 is used Especially DeltaE 94 can use different ratios between chromatic and luminance errors Sometime general statements like below AE 3 everything is OK can be found As a result it is impossible to compare the validation results of product A with product B There are too many unknown variables in use Therefore the user has some fundamental questions What settings should be used How precise is the calibration Is the monitor suited for calibration
14. ified folder On a Macintosh simply open the dmg file and start the UDACT application or copy it to the desktop or another appropriate folder on your system 1 4 Registering the software Launch the application and select the Register button Now register the UDACT to the dongle Choose the dongle as a volume and open the xxxxxx lic file Afterwards UDACT is ready to use This registration process must be performed once on any computer that s indended for using the UDACT 1 5 Selecting the measurement device Switch to the Settings button and choose the right measurement device from the list The following measurement devices for TFTs and CRTs are supported Eye One spectrophotometers Eye One Display 1 2 colorimeters Sequel Gamma 4c 4cl colorimeters Colorvision Spyder 2 Xrite Optix XR aka DTP94 colorimeters Additionally UDACT reports the name of the monitor the profile name creation date and the serial number if available To activate the measurement device please press the connect button Some measurement devices need to perform a calibration prior to the Display Analysis and Certification Tool s Settings Calibration Check Uniformity Check Summary Report Register RGB 25 0 25 0 25 0 XYZ 0 4 0 4 0 3 Lab 3 0 0 0 0 Stop Settings Calibration Check W iformity Check Summary Report Register This test measures the uniformity of the monitor
15. isplay Co o D gt zx D Display Analysis and Certification Tool amp 2 3 4 5 6 7 6 9 10 11 12 COPYRIGHT 2003 Liz 3EU230603 Device Adobe P User Ugra Verlag CH 9014 St Gal Ugra FOGRA Medienkeil CMYK EPS V2 0 The ugra fogra MediaWedge for the certification of proofs and prints ostScript Parser len 2 6 UDACT profile quality specifications The profile quality or profile consistency certifies that color inside the display s gamut can be reproduced very precisely The human eyes recognition treshold is around AE 3 That why UDACT uses an average of AE 3 and maximum of AE 6 for the profile quality acceptance Example The profile quality measurements show a maximum deviation of AE 6 2 and an average of only AE 2 0 This unit is uncertified 2 7 UDACT soft proof quality specifications The softproof quality analysis is based on the 48 patches of the ugra fogra MediaWedge These 48 patches define the target gamut ISOcoated ISOuncoated ISOnewspaper that the monitor should match with at least 90 and the average deviation should not exceed AE 4 For contract proofing the specifications define a maximum deviation of AE 5 for the primaries AE 10 for the maximum and AE 4 for the average deviation Only the average deviation is suited for the transformation of the ugra fogra MediaWedge to the screen The primaries are most likely too far out of gamut Astandard 75 NTSC unit has a Cyan d
16. low means in this case that the display should be calibrated with the end of the workflow in mind Most likely this will be a print Finally a guideline for calibrating a screen can be like the following Whitepoint 5 000 K 6 000 K Luminance at least 120 cd m2 Gradation Gamma 1 8 or L A chromatic adaption like Bradford is recommended and most of the calibration software offer this adaption by default The profile type should be a Matrix TRC type as display LUT profiles are not well supported by popular applications This basic setup will help make the match between display and viewing booth much closer Display Analysis and Certification Tool amp Settings Calibration Check Uniformity Check Summary Display Analysis and Certification Tool v1 0 4 C 2006 UGRA Name Company Serial Expires Clear Load ugra Settings Calibration Check Uniformity Check Summary Report Register Device DTP94 LCD mode CE Connect Monitor Info MonitorName MonitorProfile EDID Name EDID Serial ugra A 1 3 Installing the UDACT The UDACT is delivered on a USB stick that is also used as a dongle Thus you cannot use the UDACT application without the dongle beeing present at the computer at the same time Attach the dongle to the Windows PC and start the UDACT exe directly from the USB stick or copy UDACT application to your desktop or another user spec
17. match with the real world demands On the one hand gamuts tend to increase from TFT generation to TFT generation we can disregard CRTs as they are no longer in production and we have to devide the gamut size into a gamut quality and a gamut quantity Most of todays TFTs have a gamut size or volume of about 65 75 of NTSC NTSC has nothing to do with printing technologies but is the main basis for gamut size developments with displays New technologies like wide gamut CCFL cold cathode flueresence lights or LED backlights reach more than 100 of NTSC What does that mean for the soft proofing quality Basically the larger the gamut the better the match between display and proof or print But the raw gamut volume does not tell us anything about the real congruency to a printing standard The mentioned volumes are stated without a geographical relation inside the chromatic diagram Its very good to be seen on the left that 100 NTSC does not match 100 display NTSC Display Analysis and Certification Tool amp Even a wide gamut does not include the complete ISOcoated reference Cyan red circle ist still AE 5 A 100 NTSC 2 display offers a nearly perfect coverage of ISOcoated 1 o L u Go N F gt NN o MH FTF FT H H GCG N N o BH FH oo The primaries are always good but the graybalance upper grayscale can be unacceptable or acceptable lower grayscale Of course the 100 NTSC display shows a
18. of the test persons define the matching white Butifthewhitepointis defined to bedifferent point of a display and a viewing booth to an area thanD50 achromaticadaption function must between 5 600 K and 6 000 K be applied D50 is the color communication standard with ICC colormanagement Every device or color that uses a different whitepoint must be retransformed back to D50 This retransformation is called chromatic adaption Common chromatic adaptions are Bradford or vonKries Warm colored image parts appear to be colder than they are Thus the softproof does not match the printed results If this retransformation is done without an adaption With chromatic adaption left a te appears Additionally the display is compared to a as printed Without chromatic adaption right the viewing booth much to dark The ISO 3664 Image appears much to cold defines 1800 Lux for the light intensity The displays brightness is specified in Candela per squaremeter or nits and booth terms do not match To get the equivalent of 1800 Lux in Candela we have to devide Lux by Pi 3 1800 Lux result in something like 600 Candela None of today s displays will survive for a long time with such an intensity That s why most of the professional viewing booths have an electronic dimmer to reduce the intensity to a value that matches a displays luminance much better Most of the viewing booths can reduce their light intensity to an equivalent o
19. ronments or for general use layout only Disp la y Analysis and Certitication ool ca Settings Calibration Check Uniformity Check Summary Report Register The Monitor was tested according to the specifications of the UGRA Display Analysis and is suited for the following environments Gray Balance ED Profile Quality ED Softproof Quality ED V ISOcoated W ISOuncoated W ISOnewspaper W Layout W certified ugra ugra O Settings Calibration Check Uniformity Check Summary Report Register The Monitor was tested according to the specifications of the UGRA Display Analysis and is suited for the following environments Gray Balance SD gt lt Profile Quality DS gt lt Softproof Quality gt lt ISOcoated xX ISOuncoated x ISOnewspaper X Layout W ugra not certified ugra O Settings Calibration Check Uniformity Check Summary Report Register EDID Name Apple Cinema EDID Serial Profile Library ColorSync Profiles 18 05 06 S800K 1 8 1 50cd icc Created 2006 5 18 19 01 Measurement device DTP94 LCD mode Summary The monitor has passed the certification according to the UGRA DACT specifications Gray balance yes Profile quality yes MultiColor HighBody no Offset Gravure Paper Type 1 2 yes Offset on uncoated paper yes Newspaper Printing yes Layout yes Save Report Save Full Report ugra O TESSR
20. tween two shifted grays that is as close as AC 0 5 environment is also given The UDACT is designed with the average user in mind and can be used to certify and analyze any soft proofing display Foreseenable technological developments like the regulation of Multicolor and High Density printing have already been taken into account during the development of the ugra Display Analysis and Certification Tool Only the gamut size depends on the development of new technologies and that s why the UDACT implements a ranking for the recommended usage of the displays On the other hand gray balance and profile quality are not effected by technological evolutions Therefore the validity of the results is given for a long period 2 1 UDACT and ISO 12646 The actual revision of the ISO regulation 12646 and the upcoming revision is not intended for on the desk certification of an individual display The ISO 12646 certifies many aspects that a user simply cannot follow For example conoscopic cameras must be used to define the viewing angles and the color shift at different viewing angles Nevertheless the ISO 12646 contains some aspects that can be easily used with a desktop tool The UDACT transforms some of the scientific results of the regulation into a software that everyone can use to certify an individual display with utmost precision There is a fundamental difference between an ISO regulation that defines minimum requirements
21. y reproduces colors exactly out of the box The differences between the source color and the target have to be corrected One can do this by adjusting the data that get from the computer to the monitor In this case the VCGT video card gamma table or LUT includes a correction curve The downside is that the more the profile has to correct the less precise it is at the end A hardware calibration keeps the graphics signal untouched the VCGT contains no data and corrects the display internally The displays feature a special correction table LUT that works with very high precision up to 14bit per channel and results in a lossless color transfer During the past two years weve seen that display calibration made a great leap forwards Hardware calibrated TFTs can from the papers reproduce colors more exactly than software calibrated units but how precise are they really Is there an overlap between good software calibrated and not so good hardware calibrated ones Display Analysis and Certification Tool amp 2 5 UDACT gray balance specifications The first approach was to find a out an acceptable way to look at the gray balance criteria A perfect gray balance should be smooth on the one hand and should offer a perfect differentiation of the whole grayscale with no color shifts and noticeable banding effects The human eye recognizes deviations in the grays from AC 0 5 on But this treshold is only reachable by a
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