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HP PCL 5 User's Manual

1. Boolean Boolean Input Value Function Input Value Function 216 TDSTxax 236 SDTao 217 SDTSaoxn 237 SDTxno 218 DTSDanax 238 DSo 219 STxDSxan 239 SDTnoo 220 STDnao 240 T 221 SDno 241 TDSono 222 SDTxo 242 TDSnao 223 SDTano 243 TSno 224 TDSoa 244 TSDnao 225 TDSoxn 245 TDno 226 DSTDxax 246 TDSxo 227 TSDTaoxn 247 TDSano 228 SDTSxax 248 TDSao 229 TDSTaoxn 249 TDSxno 230 SDTSanax 250 DTo 231 STxTDxan 251 DTSnoo 232 SSTxDSxax 252 TSo 233 DSTDSanaxxn 253 TSDnoo 234 DTSao 254 DTSoo 235 DTSxno 255 1 Color Vector Graphics HP GL 2 7 13 PC Pen Color This command changes the pen color in a palette created by the IN or CID command Ec v W The PC command defaults the colors of all pens as indicated in the table below PC pen primary1 primary2 primary3 or PC pen or PC Parameter Format Functional Parameter Range Default pen integer determined by NP isee table primary clamped real 0 to 255 for those see table primary2 printers supporting primary3 the CR command the CR command determines the range pen specifies the number of the pen whose color is being defined An out of range pen parameter sets error 3 and the command is ignored The range for the pen parameter is determined by the size of the current color palette primary1 primary2 primary3 specifies the primary component values which are to be ass
2. 5 40 Set Pattern Reference Point Command 5 43 Pattern Control 5 44 Rectangular Area Fills Rules 5 45 Pattern Transparency for Rectangular Area 5 50 Contents viii EN Rectangular Fill Examples llieeeeeee I 5 52 Solid Fill Black White 5 52 Shadedi Fill 1 ERE te ner tix bred sur hebr t ioa Ru Ree 5 54 Chapter 6 Raster Graphics INTOCUCTION sa bata eas Re oe dy RG ey ha a EE EAS 6 1 PCL 5 Color Raster Graphics 6 4 Raster Graphics Command Sequence 6 6 Raster Graphics Resolution 6 8 Raster Graphics Presentation Mode 6 10 Source Raster Height Command 6 13 Source Raster Width 6 15 Start Raster Graphics Command 6 17 Raster Y Offset Command 6 19 Set Compression Method Command 6 20 Unencoded Method 0 6 21 Run length Encoding Method 1
3. C 21 Appendix D Modifying Output Color Color LaserJet 5 5M DeskJet INTOQUCUION PEE A oe eg bape epee ele ig eee ee D 1 Halftone Render Algorithms D 3 Render Algorithm Command D 3 User Defined Dithers D 6 Download Dither Matrix D 7 Multiple Dither Matrices D 10 Color Lookup Tables sia naiipit a a a teens D 13 Gamma Correction a erra iaa a eae ana a E A E Aa nn D 17 Viewing uote eae Recte re D 18 Monochrome Printing 00 59 snime n D 20 Driver Configuration D 21 Index EN Contents xi Contents EN EN Color Printing Overview Introduction This chapter provides an overview of color printing with Hewlett Packard printers A primary goal for HP color printers has always been WYSIWYG What You See Is What You Get color where the color displayed on the screen while creating a document is the same as the color in the printed document However this goal has been very difficult to realize due to a number of factors such as Some colors that can be shown on a computer display cannot be reproduced by a printer The Cyan Magenta and Yellow colors used to create the
4. To Logical Page Boundary Figure 5 10 Pattern Layout Across the Printable Area EN The PCL Print Model 5 35 Pattern Reference Point The pattern reference point is a position on the logical page at which the base pattern is positioned for tiling The upper left corner of the base pattern is positioned at this point see Figure 5 10 The default pattern reference point is position 0 0 However it is possible to set the pattern reference point to the current cursor position This allows the pattern to be positioned or adjusted for fill areas The pattern reference point may be shifted more than once for as many fill areas as there are on a page the area must be filled before the tile point is moved for the next fill area Figure 5 11 shows two areas filled with the pattern reference point fixed at the default 0 0 position The lower portion of the illustration shows two areas in which the pattern reference point was moved to the upper left corner of each area and the area filled separately 5 36 The PCL Print Model EN Pattern Reference Point at Default Position Pattern Reference Point Position at upper left corner of area before tiling filling each area Pattern Reference Point Figure 5 11 Moving Pattern Reference Point for Pattern Filling EN The PCL Print Model 5 37 Download Pattern Command The Downl
5. 6 21 Tagged Image File Format Encoding Method 2 6 21 Delta Row Compression Method 3 6 24 Adaptive Compression Method 5 6 28 Transfer Raster Data Commands 6 32 Transfer Raster Data by 6 33 Transfer Raster Data By Row Block Command 6 33 End Raster Graphics Command 6 35 Raster Scaling esses i a e mew ee ME ee eee 6 36 Raster Graphics 6 38 Color Raster Graphics 6 42 Chapter 7 Color Vector Graphics HP GL 2 Iniigoe Ueire ETE 7 1 Enter HP GE 2 Mode eoe ke Y Beebe es Re xiu e ak x ea 7 2 MC Merge 7 6 PG Pen Color espe suae te n bg nem ede AE x x Redonda ues 7 14 NP Number of Pens sslssseeesee RR en 7 17 GR Color Range EU xa eee ede cas 7 19 PP Pixel Placement ix ee xh e ge ur n RR Ao ERR n 7 20 EN Contents ix Appendix A Color Printing Overview Color LaserJet 5 5M DeskJet Introduction s ii eed ee emen Ro Gh eae ERE Ree X Race dae a RR A 1 Color Concepts ere kem dr PRU XR Pe rx E E RETE RM A 3 Palett
6. Byte 15 msb 8 7 Isb 0 Byte 0 Color space Pixel encoding mode 1 2 Bits per index Bits per primary 1 3 4 Bits per primary 2 Bits per primary 3 5 6 White reference for primary 1 sint16 7 8 White reference for primary 2 sint16 9 10 White reference for primary 3 sint16 11 12 Black reference for primary 1 sint16 13 14 Black reference for primary 2 sint16 15 16 Black reference for primary 3 sint16 17 CIE L a b Long Form The long form for the CIE L a b color space allows a larger data range than the short form defaults L 0 0 to 120 0 greater than the short form by 20 0 a 159 0 to 128 0 less than the short form by 32 0 and greater than the short form by 28 0 b 120 0 to 80 0 less than the short form by 20 0 B 18 Using Color Modes Color LaserJet 5 5M DeskJet EN Note Note EN Although the data ranges may extend beyond the default data ranges specified in the short form of the CID command the printer will clip the data to the short form data ranges Maximum and minimum values are specified for each primary color Floating point data must be linearly scaled y mx b to the range 0 255 Since a and b have no theoretical limits L a b data may be sent outside CID constraints Then data is clipped to preserve hue and compressed to the device s printable gamut CIE L a b color space support is at HP Color LaserJet level for HP Color La
7. B 4 PCL Imaging B 6 Configure Image Data CID B 6 Short Form of CID Command Configure Image Data B 15 Long Form of CID Command Configure Image Data B 17 HP GL 2 Imaging B 28 Appendix C Using Palettes Color LaserJet 5 5M DeskJet Introduction used o rege nee ewes mex nee eee x exe eee LS C 1 Saving the C 3 Push Pop Palette C 3 Palette Management by ID C 5 Palette Control ID a cec eee ad E err seed eee ka eee ek C 8 Palette Control lille C 9 Simple Color C 11 CID Color C 13 HP GL 2 Palettes 2 teeta eR eed e Eon eR RE nen dor peo C 16 Foreground Color anaana cette eens C 18 Contents x EN Programming Color C 20 Color Component One C 20 Color Component TWO C 20 Color Component C 21 Assign Color
8. Pen Color Assignment PC The IN command always establishes the 8 pen palette Two Pens Pen Number Color 0 White 1 Black Four Pens Pen Number Color 0 White 1 Black 2 Red 3 Green Using Palettes 3 15 Eight Pens Pen Number Color White Black Red Green Yellow Blue Magenta Cyan Black 3 16 Using Palettes EN Foreground Color All PCL marking entities utilize foreground color which is selected from the current palette using the Foreground Color command Ec v S Foreground color interacts with raster color depending on the print model commands in effect Foreground Color Command The Foreground Color command sets the foreground color to the specified index of the current palette Ec vitS Index number into current palette Default 0 Range Oto 2 current palette size _ 4 Specified values that are out of range of the current palette are mapped into a new index as follows Index Specified foreground index modulo palette size For example specifying a foreground color index of 10 when the current palette size is 8 maps to 10 modulo 8 which is equal to 2 If the current palette was created under HP GL 2 the index is mapped according to the HP GL 2 mapping function Foreground color affects the following PCL page marking primitives Text characters they change to the foreground
9. Refer to the preceding definitions and the discussion of Figure 5 2 and Figure 5 3 for an explanation of the effects of pattern transparency 5 8 The PCL Print Model EN Logical Operations EN The basic print model defines how a pattern source image and destination image are applied to each other using the print model s transparent and opaque modes to produce a resulting image The Logical Operations Ec 2 O command specifies which logical operation is to be performed on the source texture and destination to produce a new destination Transparency modes should be specified before the logical operation is performed or printable data is sent The print model process consists of the following steps 1 Specify source and or pattern transparency modes if desired 2 Specify the logical operation or use the default 3 Define the desired operands source destination pattern Definitions Source The source image may be one of the following HP GL 2 primitives Rules Characters Raster images single plane mask or multiplane color Destination The destination image contains whatever is currently defined on the page It includes any images placed through previous operations Pattern or Texture The pattern is defined by the Select Current Pattern command Ec v T The terms pattern and texture are used interchangeably in this section Transparency Modes The white pixels of the source and or pattern may be mad
10. Error diffusion Continuous tone smooth 150 Ipi Monochrome device best dither Monochrome continuous tone smooth 150 Ipi Monochrome error diffusion Monochrome continuous tone smooth 150 Ipi Cluster ordered dither Continuous tone smooth 150 Ipi Monochrome cluster ordered dither Monochrome continuous tone smooth 150 Ipi User defined dither Continuous tone smooth 150 Ipi Monochrome user defined dither Monochrome continuous tone smooth 150 Ipi Ordered dither Continuous tone smooth 150 Ipi Monochrome ordered dither Monochrome continuous tone smooth 150 Ipi Noise ordered dither Continuous tone smooth 150 Ipi Monochrome continuous tone smooth 150 Ipi Monochrome noise ordered dither User Defined Dithers The Download Dither Matrix command Ec m W can create a dither matrix for one or all three primary colors in effect providing halftone screens User defined dither matrices can be used for optimizing the printer s output capabilities when using device dependent color spaces They are ignored for device independent color spaces since the printer cannot be calibrated as is necessary for device independent color User defined halftones can be downloaded for each component of the color space D 6 Modifying Output Color Color LaserJet 5 5M DeskJet EN Note EN A user defined matrix is defined in additive colors RGB values The dither matrix pixels are defined in terms of device dependent resolution Wh
11. lb o ff jo H o h o 0 o h Jo b 762 0 1 0 0 1 b b lo backjo lo lbo bo ROPs in the CMY Color Space The CMY ROP truth tables in Table 5 2 shows examples of how the ROPs number determines the value of the Destination for all combinations of Texture Source and Destination In the CMY color space a 0 is the absence of ink white and a 1 is the presence of ink black the opposite of the RGB color space value for black and white Therefore the ROPs results Destination values for the CMY color space are the opposite negation of the RGB values However a CMY ROP is easier to use when determining if the page is marked since a 1 denotes marking EN The PCL Print Model 5 15 Table 5 2 CMY ROP Truth Tables 252 ROP ey 90 n 00000011 10100101 n b7bgbsb b3b2b4bp T s D Tsi D D S DROP D o lo lo O 1 lo 0 b 17 0 1 o lo H 0 lo bg b6 4 o M 0 M 0 bs b5 0 H HM 0 MH hM o 0 M 1 b 1 o Jo Jo 1 lo Jo lo 1 lo lo b 1 H o 1 HH Ph 1 1 ibp 2 1 1 j fi 1 d jo 16 1 1 o b 1 d ft d eek by bo Using a ROP The first step in using a ROP is to determine which color space you re in RGB or CMY Then deter
12. Ec c2P This example prints the following 300 400 Figure 5 14 Shaded Fill Example EN The PCL Print Model 5 55 5 56 The PCL Print Model EN EN 6 Raster Graphics Introduction A raster image is a made up of a series of discrete picture elements pixels Pictures such as those in newspapers television and documents from Hewlett Packard printers are examples of raster images In comparison pictures drawn with lines and geometric objects such as circles rectangles and polygons are termed vector graphic images While some pictures could be produced using either vector or raster graphics raster graphics is best suited for printing photographic images A raster image is invariably rectangular and divided into a gridwork of pixels Each pixel represents a small area of the image In monochrome images each pixel represents a black or white dot In color images each pixel is a colored dot Therefore the most important characteristics of an image are its Image width Image height Image resolution the number of dots or pixels per inch An image is also divided into rows where a row is a grouping of all the pixels in a horizontal strip of the image the width of the image and one pixel high As noted before a pixel represents a small area of the image The size of the area depends on the resolution of the image The pixel area for a 600 dot per inch dpi image is a square 1 600th of a inch on a side Courser reso
13. color printing overview 1 1 A 1 color range CR command 7 19 color selection and palettes 1 6 color spaces 1 3 color specifications 1 3 color vector graphics HP GL 2 7 1 Colorimetric RGB color space B 20 command finish mode 4 6 logical operation 5 13 pixel placement 5 27 commands PCL Ec c G Pattern Area Fill ID 5 29 End Raster Graphics 6 35 pattern control 5 44 pattern ID 5 29 pattern transparency mode 5 8 raster graphics presentation 6 10 raster graphics resolution 6 8 raster graphics start 6 17 Raster Height command 6 13 Raster Width command 6 15 raster y offset 6 19 Select Current Pattern command 5 32 Set Pattern Reference Point 5 43 Set Raster Compression Method 6 20 Source Transparency Mode 5 7 Index 1 Index 2 transfer raster data 6 32 user defined pattern 5 38 compression adaptive 6 29 adaptive operation hints 6 31 byte counts 6 34 delta row 6 20 6 24 6 27 raster data 6 15 6 23 run length 6 21 TIFF 6 21 TIFF raster data 6 20 compression method adaptive 6 28 delta row 6 24 run length encoding 6 21 setting 6 20 TIFF 6 21 unencoded 6 21 Configure Image Data CID command 2 5 B 6 examples B 25 long form B 17 short form B 15 continuation user defined pattern descriptor 5 39 control bytes adaptive compression 6 29 CR color range command 7 19 cross hatch patterns selection 5 29 current pattern 5 2 Current Pattern command 5 32 cursor positioning adaptive compression 6 31 raster graphic
14. current Y cursor position Specifying the raster width and raster height improves memory usage Therefore it is highly recommended This command fills the raster area to the full raster height with zeroed rows Unspecified rows map to either white or transparent depending on the source transparency mode this is true only if index 0 is white When a Transfer Raster Data command is received that causes any raster row to extend beyond the row boundary set by the Raster Height command the row outside the boundary is clipped This includes the case where the cursor is moved beyond the height boundary with a Raster Y Offset command and the printing of raster data is attempted If you have specified either a raster height or a raster width of 0 and a Start Raster Graphics or Transfer Raster Data command is received then the entire raster graphic is clipped If both a raster height and a raster width are specified non zero and a Start Raster Graphics or Transfer Raster Data command is received then the raster area is guaranteed to be filled For color printers a zero fill is not necessarily white If the raster height is not set no padding or clipping of rows takes place Raster Graphics 6 13 This command is ignored after the Start Raster Graphics or Transfer Raster Data commands until the next End Raster Graphics command Note Only raster data appearing within the intersection of the logical page the printable area and if
15. 0 Range 0 or 770 command is ignored for other values sign is ignored A value of 0 resets or initializes the color lookup tables for each primary to the unity curve 1 1 A value of 770 means the data for a color lookup table will be following The command is ignored and the data is absorbed for any number of bytes not equal to 0 or 770 Modifying Output Color Color LaserJet 5 5M DeskJet D 13 255 Unity Color Lookup Table Data Values 0 1 2 100 255 255 Gamma Color lookup Table Data Values 0 255 1 254 2 253 255 0 Inversion Color Lookup Table Data Values Figure D 1 Color Lookup Tables This command enables the color lookup tables until an FCE Configure Image Data CID or another Color Lookup Tables command with a O value field is received Note RGB gamma correction Ec t l and color lookup tables for device dependent color spaces are mutually exclusive and overwrite each other D 14 Modifying Output Color Color LaserJet 5 5M DeskJet EN As shown below the 256 point by point transformation curve for each primary color is defined sequentially for a total of 768 bytes with the additional 2 bytes for specifying the color space and reserved data field Byte 15 msb 7 Isb 0 Byte Color Space Reserved Data Field 1 Color Component 1 Index 1 Color Component 1 Index 2 3 4 Color Component 1 Index 3 Color Comp
16. 11110000 00000000 Fc b4W 0 0 240 0 5 00000000 00000000 11111000 00000000 Fc b4W 0 0 248 0 6 00000000 00000000 11111100 00000000 Fc b4W 0 0 252 0 7 00000000 00000000 11111110 00000000 EFc b4W 0 0 254 0 8 00000000 00000000 11111111 00000000 Fc b4W 0 0 255 0 9 00000000 00000000 11111111 10000000 Fc b4W 0 0 255 128 10 11111111 11111111 11111111 11000000 Fc b4W 255 255 255 192 11 11111111 11111111 11111111 11100000 Ec b4W 255 255 255 224 12 11111111 11111111 11111111 11110000 Ec b4W 255 255 255 240 13 11111111 11111111 11111111 11111000 Ec b4W 255 255 255 248 14 11111111 11111111 11111111 11111100 Ec b4W 255 255 255 252 15 11111111 11111111 11111111 11111110 Ec b4W 255 255 255 254 16 11111111 11111111 11111111 11111111 Ec b4W 255 255 255 255 EN Raster Graphics 6 39 Example of Raster Graphic Image Data Raster Image Data Command Data Bod byte 1 byte 2 byte 3 byte 4 Decimal Equivalent 17 11111111 11111111 11111111 111111111 Ec b4W 255 255 255 255 18 11111111 11111111 11111111 11111110 Ec b4W 255 255 255 254 19 11111111 11111111 11111111 11111100 Ec b4W 255 255 255 252 20 11111111 11111111 11111111 11111000 Ec b4W 255 255 255 248 21 11111111 11111111 11111111 11110000 Ec b4W 255 255 255 240 22 11111111 11111111 11111111 11100000 Ec b4W 255 255 255 224 23 11111111 11111111 11111111 11000000
17. 2 8 Bits Primary 3 8 lt ESC gt t600R Change graphics resolution 600 lt ESC gt r600S Set Source Raster Width 600 pixel units lt ESC gt r300T Set Source Raster Height 300 pixel units lt ESC gt r0A Activate graphics mode lt ESC gt b0OM Compression method unencoded lt ESC gt b W Transfer raster data row 1 600 bytes lt ESC gt b3M Compression method delta row lt ESC gt b W Transfer raster data 299 600 bytes lt ESC gt rC End raster graphics lt gt Reset In the textual equivalent of the PCL 5 commands shown below the following character representations are used Vestands for the ASCII escape character e ris a carriage return X00 to x07 are the single byte binary values from 00 to 07 6 42 Raster Graphics EN EN Looking at the PCL commands you ll notice that the first row is sent unencoded and then the remaining rows replicated by switching to delta row encoding and sending 299 zero rows This method depends on two features of the PCL 5 command set 1 The 1st row became the seed row at the end of the first row transfer command 2 When in Delta Row compression mode zero length transfers cause the seed row to be replicated The first row is actually a good candidate for run length or TIFF pack bits encoding but is not encoded for clarity eE r e v6W x00 x01 x08 x08 x08 x08 r e t600R e r600S e r300T e r0A e bOM r e b600W x
18. 6 34 D data block adaptive compression 6 28 data compression raster data 6 15 data range scaling B 16 data user defined pattern 5 39 default palettes 3 15 C 16 delta row compression adaptive compression 6 29 6 31 raster graphics 6 20 6 24 descriptor user defined pattern header 5 38 destination image 5 2 destination raster height command 6 37 destination raster width command 6 37 device CMY color space B 18 device RGB color space B 17 device dependent color A 10 device independent color A 10 direct color selection A 5 dither patterns 4 2 D 3 user defined dithers D 6 dithers download dither matrix command D 7 multiple dither matrices D 10 download dither matrix command D 7 download pattern command 5 38 driver configuration command 4 4 D 21 duplicate row adaptive compression 6 29 E empty row adaptive compression 6 29 encoding by pixel A 7 by plane A 6 end raster graphics command 6 35 enter HP GL 2 mode 7 2 escape sequences PCL Ec b M Set Compression Method 6 20 Ec b Y Raster Y Offset 6 19 Ec c Q Pattern Control 5 44 Ec c W User Defined Pattern 5 38 Ec e R Pixel Placement Command 5 27 Ec 2 O Logical Operation 5 13 Ec p R Set Pattern Reference Point 5 43 Ec r F Raster Graphics Presentation 6 10 Ec r T Raster Height 6 13 Ec r T Raster Width 6 15 Ec t R Raster Graphics Resolution 6 8 Ec v N Source Transparency Mode 5 7 Ec v 0O Pattern Transparency mode 5 8 Ec v T Select Current
19. Binary value Decimal value 1 0000 0000 1 to to to 127 0111 1111 127 No Operation Value NOP value Binary value Decimal value 128 128 1000 0000 128 Repeated Pattern Values of Repetitions Binary value Decimal value 1 1 1111 1111 255 to to to 127 127 1000 0001 129 These negative values are represented by taking the twos complement of the value of the number 6 22 Raster Graphics EN Note Note Another method to calculate the number needed in the control byte for some number of repetitions is to subtract the number of desired repetitions from 256 For example the control value for 3 repetitions 4 occurrences of a byte is 256 minus 3 253 A zero or positive value in the control byte means that the subsequent byte or bytes are non replicated bytes of data The value of the control byte plus one indicates the number of data bytes that follow For example a control byte of 0 means the following 1 byte is literal raster data A control byte of 6 indicates that the following 7 bytes are literal raster data bytes TIFF encoding also allows you to include a non operative NOP control byte represented by the value 128 This byte is ignored and the subsequent byte is treated as the new control byte It is more efficient to code two consecutive identical bytes as a repeated byte If these bytes are preceded and followed by literal bytes however it is more efficient to code the entire group as literal bytes
20. C 6 palettes 3 1 A 1 A 3 C 1 CID color 3 13 C 13 control 3 9 C 9 Control ID 3 8 C 8 default 3 15 C 16 device CMY 3 14 C 15 device RGB 3 13 C 13 device independent 3 14 C 15 HP GL 2 3 15 C 16 management by ID 3 5 C 5 palette stack 3 5 C 5 palette store 3 5 C 5 programming 3 19 C 20 saving 3 3 C 3 select palette command 3 6 C 6 simple color 3 11 C 11 palettes and color selection 1 6 pattern current 5 2 reference point 5 36 shading 5 30 user defined 5 33 pattern control command 5 44 patterns 5 44 Pattern ID Area Fill ID command 5 29 pattern transparency 5 50 pattern transparency mode 5 3 Pattern Transparency Mode command 5 8 patterns 5 2 download pattern command 5 38 filling with 5 28 reference point 5 36 Select current pattern command 5 32 Set pattern reference point command 5 43 tiling 5 34 user defined patterns 5 33 PC pen color command 7 14 PCL 5 color concepts 1 3 PCL 5 color graphics context 1 6 PCL 5 color mode 1 6 PCL 5 Comparison Guide vi PCL 5 raster images 1 7 PCL imaging mode 2 2 2 5 B 2 B 6 PCL print model 5 1 PCL PJL Technical Quick Reference Guide vi pen color PC command 7 14 pixel encoding A 6 A 7 user defined pattern descriptor 5 39 pixel placement 5 24 5 27 command 5 27 HP GL 2 command 7 22 PCL command 5 27 pixel placement PP command 7 20 7 22 pixel placement command 5 27 Index 3 Index 4 pixels and pixel encoding 1 7 plane encoding A 6 position rectangular
21. D i j the point corresponding to x y is intensified otherwise it is not The intensity of each primary color is determined according to this scheme The relationship between and D depends on the specified color space Monochrome Rendering Monochrome rendering generates a gray value from the three primary colors The gray value is computed according to the NTSC standard which for the Device RGB color space is Gray 0 3 x Red 0 59 x Green 0 11 x Blue User Defined Dithering For a user defined dither the input primaries are compared against differently dimensioned dithers e g MxN which may vary for each primary color Note Render algorithms 1 2 9 and 10 are not accessible when in a device independent color space because it is impossible to characterize a printer for all possible dither algorithms If one of these render algorithms is selected when in a device independent color space the device best dither algorithm will be used instead HP Color LaserJet 5 and 5M printers do not support user defined dithering EN Modifying Output Color Color LaserJet 5 5M DeskJet D 5 Non Continuous Tone Algorithms HP Color LaserJet 5 and 5M printers remap non continuous tone render algorithms into continuous tone algorithms The following remapping takes place Snap to primaries Snap to primaries Snap black to white color to black Snap black to white color to black Device best dither Continuous tone smooth 150 Ipi
22. EN Continuation Byte 1 This field byte 1 must be set to 0 This byte is for future printer support and does not currently provide any continuation operation Pixel Encoding Byte 2 The bits index field may be either 1 or 8 If the value is 1 the color of each pattern dot is specified by a single bit supporting a two color palette which need not be black and white If the value is 8 the color of each pattern dot is specified by one byte of data allowing 256 colors If the value of any byte is greater than the current palette size the modulo function is applied when rendering 7 5 4 3 0 000 Unused Bits Index Reserved Byte 3 This field byte 3 is not currently used and must be set to 0 Height in Pixels Bytes 4 and 5 This field bytes 4 and 5 identifies the number of raster rows height of the pattern specified at device resolution If the height is 0 the data is ignored and no pattern is defined Pattern height must be less than 32767 pixels Width in Pixels Bytes 6 and 7 This field bytes 6 and 7 identifies the number of pixels width of the pattern specified at device resolution If the width is 0 the data is ignored and no pattern is defined Pattern width must be less than 32767 pixels Pattern Image This field contains the raster data for the pattern Data rows must be word aligned Pattern image data is formatted differently for each format type see the data descript
23. Examples Run length and TIFF Compression The following examples show how a raster row can be coded using run length and TIFF compression methods Note that the compression examples use characters to represent the binary data stream Byte Number Bits ASCII 1 2 3 4 5 6 7 01010101 01010101 01010101 01010101 01000001 01010100 01010100 U U U U A T T EN Unencoded EC r1A Ec bOm7WUUUUATT Ec rC Raster Graphics 6 23 Run length Encoding EC r1A Ec b1meW 3 U 0 A 1 T Ec rC TIFF Encoding EC r1A Ec b2m6W 3 U 0 A 1 T or Ec b2m6W 3 U 2 ATT Ec rC In the TIFF encoding example above parenthetical expressions are used to identify control bytes For example the byte 3 is shown to represent the control byte for a repetition minus value of 3 The actual value for this position is the decimal value 253 Additional encoded control bytes in this sequence include 0 for decimal 0 1 for decimal 255 and 2 for decimal 2 The raster data pattern bytes are represented by the ASCII character Delta Row Compression Method 3 Delta row compression identifies a section of bytes in a row that is different from the preceding row and then transmits only that data that is different the delta data If a row is completely different from its preceding row then the entire row must be sent as the delta which is not very efficient if only one bit is different then only one byte is identified and
24. Pattern Command 5 32 F Faster Y Offset command 6 19 fill rectangular area command 5 48 finish mode command 4 6 foreground color 5 2 foreground color command 3 17 C 18 format field user defined pattern descriptor 5 38 G gamma correction A 2 D 17 gamma correction command D 17 graphic patterns 5 29 graphics raster 6 1 special effects 5 1 EN EN transparency mode 5 2 user defined patterns 5 33 grid centered pixel 5 27 grid intersection pixel 5 27 H halftone render algorithms 4 2 A 2 D 3 height pixels user defined pattern descriptor 5 39 Horizontal Rectangle Size command 5 46 HP GL 2 graphics 7 1 HP GL 2 imaging mode 2 2 2 13 B 3 B 28 HP GL 2 pixel placement command 7 22 l ICC profiles 1 4 illumination models A 13 image raster 6 1 indexed color selection A 5 L logical operation command 5 13 logical operations 5 3 5 9 and transparency interactions 5 12 long form CID command B 17 luminance chrominance color space B 22 M manual organization iv matching color A 11 MC merge control command 7 6 memory raster graphics usage 6 8 merge control MC command 7 6 monochrome print mode command 4 3 D 20 monochrome printing 4 3 D 20 N NP number of pens command 7 17 number of pens NP command 7 17 operations logical 5 9 orientation raster graphics 6 10 overview 1 1 A 1 P page marking primitives A 14 palette control ID 3 8 C 8 palette select 3 6
25. TDSanan 117 DSTnoan 144 TDSxna 118 SDTSnaox 145 SDTSnoaxn 119 DSan 146 DTSDToaxx 120 TDSax 147 STDaxn 121 DSTDSoaxxn 148 TSDTSoaxx 122 DTSDnoax 149 DTSaxn 123 SDTxnan 150 DTSxx 124 STDSnoax 151 TSDTSonoxx 125 DTSxnan 152 SDTSonoxn 126 STxDSxo 153 DSxn 127 DTSaan 154 DTSnax 128 DTSaa 155 SDTSoaxn 129 STxDSxon 156 STDnax 130 DTSxna 157 DSTDoaxn 131 STDSnoaxn 158 DSTDSaoxx 132 SDTxna 159 TDSxan 133 TDSTnoaxn 160 DTa 134 DSTDSoaxx 161 TDSTnaoxn EN Color Vector Graphics HP GL 2 7 11 Table 7 1 Logical Operations ROP3 continued Boolean Boolean Input Value Function Input Value Function 162 DTSnoa 189 SDxTDxan 163 DTSDxoxn 190 DTSxo 164 TDSTonoxn 191 DTSano 165 TDxn 192 TSa 166 DSTnax 193 STDSnaoxn 167 TDSToaxn 194 STDSonoxn 168 DTSoa 195 TSxn 169 DTSoxn 196 STDnoa 170 D 197 STDSxoxn 171 DTSono 198 SDTnax 172 STDSxax 199 TSDToaxn 173 DTSDaoxn 200 SDToa 174 DSTnao 201 STDoxn 175 DTno 202 DTSDxax 176 TDSnoa 203 STDSaoxn 177 TDSTxoxn 204 S 178 SSTxDSxox 205 SDTono 179 SDTanan 206 SDTnao 180 TSDnax 207 STno 181 DTSDoaxn 208 TSDnoa 182 DTSDTaoxx 209 TSDTxoxn 183 SDTxan 210 TDSnax 184 TSDTxax 211 STDSoaxn 185 DSTDaoxn 212 SSTxTDxax 186 DTSnao 213 DTSanan 187 DSno 214 TSDTSaoxx 188 STDSanax 215 DTSxan 7 12 Color Vector Graphics HP GL 2 EN Table 7 1 Logical Operations ROP3 continued
26. UEL command or until the printer power is switched off and on The value field determines the cursor position once HP GL 2 mode is entered Note HP Color LaserJet printers do not support 1 Ec962B or Ec 3B 1 A value field of 1 creates a single context or stand alone plotter mode which has the following effects The current page is closed and printed and the HP GL 2 environment is initialized IN commana HP GL 2 output begins on a new page HP GL 2 and PCL output cannot be combined on the same page No PCL commands except FcE and the PJL command 12345 are recognized by the printer The PCL picture presentation directives are ignored 7 2 Color Vector Graphics HP GL 2 EN EN e The command closes HP GL 2 prints the current page and performs an before entering PCL e The default HP GL 2 orientation is reverse landscape e Hard clip limits are equal to the printable area e The FcE command functions as usual When the single context mode is used 1 the following steps should be followed 1 Enter HP GL 2 mode using the Ec96 1B command 2 Transmit one or more HP GL 2 drawings 3 Exit HP GL 2 mode 0 This parameter option Fc 0B sets the pen position to the previous HP GL 2 position if this is the first time HP GL 2 mode is entered in the present print job assuming an has been sent the pen position is at
27. a color monitor are combinations of different colored lights traveling directly to the eye They are called additive colors since the different colors combine to form the resulting color The colors seen on a printed material such as paper are reflected from the paper surface which absorbs some of the light Colors seen under these conditions depend on the viewing conditions the amount and color of ambient light as well as the amount and color of the reflected light Color Specifications and Color Spaces A given color can be described as particular amounts of three light frequencies red green and blue light For example equal amounts of red green and blue light are perceived as white light The absence of all three primary light colors is black EN Color Printing Overview 1 3 Color can be described in ways other than amounts of red green and blue light Generally these color specification systems are known as color spaces For example The Cyan Magenta Yellow CMY color space is used to describe colors that are printed by depositing varying amounts of these three ink pigments Cyan Magenta Yellow The absence of pigment is considered to be white and the presence of all three is black The CMYK color space is similar to the CMY color space but black pigment is used in place of 10096 C M Y since imperfections in the hues of the C M Y pigments yield a dark brown rather than black A color specification then depends on
28. a value field of 2 or 3 Fc r2A or Ec r3A Ec t H Width in decipoints Default Right logical page boundary minus left graphics margin Range 0 32767 0000 values outside the range are ignored Zero or absent values default the destination width to a value that preserves isotropic scaling A specified width that would cross the right physical page boundary is clipped at the right physical page boundary but the scale factor is maintained Destination Raster Height The Destination Raster Height command defines the height in decipoints of the destination raster picture denoted by the next Start Raster command which must have a value field of 2 or 3 FC r2A or Ec r3A Ec tz V Height in decipoints Default Bottom logical page boundary minus vertical CAP Range 0 32767 0000 values outside the range are ignored Zero or absent values default the destination height to a value that preserves isotropic scaling A specified height that is longer than the physical page is clipped at the bottom of the physical page but the scale factor is maintained Raster Graphics 6 37 Raster Graphics Example To transfer an unencoded arrow shaped raster graphic image see Figure 6 7 in the shape of an arrow perform the following steps notice the well behaved raster sequence is utilized 1 Position the cursor Ec p300x400Y Move the cursor to PCL Unit position 800 400 within the PCL coordinate system 2 Sp
29. a viewing illuminant condition Ec i W binary data Number of binary bytes of data Default Range 8 8 command is ignored for invalid values signs in the value field are ignored The binary data field is formatted as follows Byte 15 msb 8 7 Isb 0 Byte 0 x chromaticity white point Isw 1 2 x chromaticity white point msw 3 4 y chromaticity white point Isw 5 6 y chromaticity white point msw 7 The above firnat adheres to the IEEE floating point format as follows 31 30 23 22 0 Sign Exponent Fractional Portion D 18 Modifying Output Color Color LaserJet 5 5M DeskJet EN EN The PCL default viewing illuminant is D65 6500K Below is a table of viewing illuminants and their chromaticity values y chromaticity 5630K Illuminant x chromaticity Daylight D65 6500K 0 3127 0 3290 Tungsten 3200K 0 4476 0 4074 Cool White Fluorescent 0 3904 0 3914 This command affects only device independent color The command acts like a state variable it is ignored for White Black Device RGB or Device CMY palettes but it becomes active when a new CID command specifies a device independent color space Modifying Output Color Color LaserJet 5 5M DeskJet D 19 Monochrome Printing The Monochrome Print Mode command converts each color value to its grayscale equivalent This improves throughput costs less to print and elimi
30. are rendered Each halftone render algorithm produces a different affect on the output varying the texture and color appearance of the printed image To choose the type of rendering to be used use the Render Algorithm command described below This command allows you to choose one of the existing rendering algorithms or to choose a user defined pattern created with the Download Dither Matrix command Render Algorithm Command The Render Algorithm command selects the algorithm to be used for rendering page marking entities on a given page Ec t J 0 Continuous tone device best dither 1 Snap to primaries Snap black to white color to black Device best dither Error diffusion Monochrome device best dither Monochrome error diffusion Cluster ordered dither Monochrome cluster ordered dither User defined dither qo o N OO 4 CQ Iv 1 Monochrome user defined dither Ordered dither Monochrome ordered dither N 1 1 1 Noise ordered dither A i Monochrome noise ordered dither i 1 Continuous tone smooth 150 EN Modifying Output Color Color LaserJet 5 5M DeskJet D 3 16 Monochrome continuous tone detail 300 Ipi 17 Monochrome continuous tone smooth 150 Ipi 18 Continuous tone basic 100 19 Monochrome continuous tone basic 100 Ipi Default 3 Range Oto 19 invalid values are ignored values 1 2 9 and 10 are ignore
31. area 5 49 PP pixel placement command 7 20 7 22 PP command HP GL 2 7 22 primitives A 14 print model A 1 command sequence 5 6 current pattern 5 2 destination image 5 1 logical operations and transparency 5 12 pattern 5 1 pattern ID area fill ID command 5 29 pattern transparency mode 5 2 5 8 rectangular area fills 5 45 rectangular areas pattern ID command 5 29 Select Current Pattern command 5 32 source image 5 1 source transparency mode 5 2 printable area raster graphics 6 7 printing patterns shading 5 29 raster graphic resolution 6 8 push pop palette command 3 3 C 3 R raster graphics 6 1 6 7 adaptive compression 6 28 clipping 6 13 command sequence 6 6 compression 6 20 6 27 compression example 6 23 6 27 compression byte counts 6 34 compression coding efficiency 6 23 compression TIFF Encoding 6 21 data block 6 28 data compressions reduction 6 15 delta row compression 6 20 6 24 End command 6 35 end raster graphics command 6 35 Height command 6 13 image 6 1 left margin 6 17 memory usage 6 8 orientation 6 10 presentation 6 17 presentation mode 6 17 printable area 6 7 printing zeroed row 6 27 raster area height 6 13 raster graphics presentation mode command 6 10 Raster Y Offset command 6 19 repeating row 6 27 resolution 6 17 run length data compression 6 20 6 21 seed row 6 26 Set Compression Method command 6 20 Start command 6 17 termination command 6 35 termination implied 6 17 TIFF data comp
32. area are clipped Byte Counts and the TIFF v4 0 Compression Mode The byte count of the value field in the Transfer Raster Data command has precedence over the literal or the command byte byte count of the TIFF v 4 0 compression mode For example the command Ec b2m3W binary data sets compression method 2 TIFF v 4 0 and sends 3 bytes of raster data for the row Suppose the binary data appears as follows 00000010 00000001 00000001 00000001 The control first byte value of 2 indicates that 3 bytes of literal unencoded raster data will follow The Transfer Raster Data command however specified only three bytes total including the control byte in the raster row The control byte and the following two data bytes are read and the remaining data byte is ignored If the last byte indicated by the value field in the Transfer Raster Data command is a control byte that byte is ignored If a Transfer Raster Data command is received without an accompanying Start Raster Graphics command any preceding start raster values are used such as left graphics margin raster height and width etc 6 34 Raster Graphics EN End Raster Graphics Command The End Raster Graphics command signifies the end of a raster graphic data transfer Ec rC Receipt of this command causes 5 operations Resets the raster compression seed row to zeros Moves the cursor to the raster row immediately following the end of the raster area if
33. bytes in the block of rows For the other compression methods the Transfer Raster Data command is sent at the beginning of each row and the value field identifies the number of bytes for that row only 6 28 Raster Graphics EN The size of a block is limited to 32 767 bytes 32 767 bytes is the number of compressed bytes and not the size of the uncompressed data To transfer greater than 32 767 bytes send multiple blocks Adaptive compression uses three control bytes at the beginning of each row within the block The first of these bytes the command byte identifies the type of compression for the row The two following bytes identify the number of bytes or rows involved The format for adaptive compression raster rows is shown below command byte gt lt of bytes rows upper byte gt lt of bytes rows lower byte first raster row byte last raster row byte gt EN The command byte designates the compression method empty row or row duplication Command byte values are shown below Value Compression Operation 0 Unencoded 1 Run Length Encoding 2 Tagged Image File Format TIFF rev 4 0 3 Delta row 4 Empty row 5 Duplicate row Raster Graphics 6 29 For command byte values 0 the two st of bytes rows gt bytes specify the number of bytes row length for the row For command byte values 4 and 5 these bytes identify the number of empty or duplicate rows to p
34. color including underlining Solid or monochrome patterned rectangular area fills rules Monochrome patterns except HP GL 2 Raster images The following are not affected User defined color patterns format 1 download patterns HP GL 2 marking primitives HP GL 2 uses selected pen but ignores foreground color EN Using Palettes 3 17 Note Foreground color interacts with color raster images In the printer all color raster is resolved into three binary raster planes of CMY Foreground color is applied to these planes modifying the color image For no interaction set foreground color to black when sending color raster images After a foreground color is selected changing any of the following will not change foreground color until a new Foreground Color command Ec v S is issued Active Palette Configure Image Data CID command Render Algorithm 3 18 Using Palettes EN Programming Color Palettes EN Except for the default black and white palette or the Simple Color palettes Fc ritU palette entries can be modified The three primary components of a color are specified and the resulting color is assigned to the palette entry indicated by Ec v l In the explanation below the term component refers to the color space primary colors For example if the current color space is sRGB component 1 indicates R component 2 indicates G and component 3 indicates B Color Component One This comm
35. color are calibrated to precise color standards Black and White References Device dependent color specifications are based upon an arbitrary range of values for each primary color component The range endpoints for each color component are called black and white references for that component Colors relative to these predefined limits are derived by specifying the amount of each component For the Device RGB color space the maximum limit is called the white reference and the minimum limit is called the black reference Regardless of the number chosen the white reference represents the maximum value of a primary color that a device can produce and the black reference represents the minimum value of that primary color For example if 100 is chosen as the white reference for red in the RGB color model it represents the reddest red the device can produce If 10 were chosen instead then 10 would represent the same red A 4 Color Printing Overview Color LaserJet 5 5M DeskJet EN EN Example Assuming the white and black references are set as follows Scenario 1 White Reference Black Reference red 63 red 0 green 63 green 0 blue 63 blue 0 Scenario 2 White Reference Black Reference red 63 red 4 green 127 green 0 blue 31 blue 0 Using these reference values 50 blue for scenario 1 is 31 and 50 blue for scenario 2 is 15 Color Selection The HP colo
36. colors specified in a document can differ in hue and quality from printer to printer even printers from the same manufacturer Furthermore the colors produced by a given printer can change over time due to internal changes as well as temperature and humidity Until recently these and other problems have led HP to approach color matching by presenting a PCL 5 color command set giving users the ability to make both major and minor color print quality adjustments However the emergence of sRGB standard Red Green Blue as an international color data standard and the growing sophistication of Hewlett Packard printers has allowed HP to provide high quality WYSIWYG color documents with a much simpler PCL color command set Therefore this manual has two main parts Chapters 1 through 7 present the latest simplified PCL 5 color command set and the appendices describe the command set described in Chapters 1 through 4 as they are supported by the Color LaserJet Color LaserJet 5 DeskJet 1200C and DeskJet 1600C printers Chapters 5 7 pertain to both sets of printers Color Printing Overview 1 1 Working with color documents A document can be thought of as a series of text characters vector graphics objects and images The parts of a document either have color specifications in them as do color images or have color specifications applied to them as do color vectors or text For color images the PCL 5 command set provides a way to spe
37. command involves sending just the common 6 byte header By changing the value of byte 0 color space the short form can specify the following five color spaces Device RGB Ec veW 0x0O Device CMY Ec v6W 0x01 e CIE L a b Ec v6W 0x03 The following data ranges are allowed in CIE L a b Hue is preserved when out of range data is clipped L 0 0 to 100 0 a 100 0 to 100 0 b 2 100 0 to 100 0 CIE L a b color space support is at HP Color LaserJet level for HP Color LaserJet 5 and 5M printers e Colorimetric RGB SMPTE RGB Fc v6W 0x02 Non linear SMPTE RGB with a 2 2 gamma and 1 0 gain is the default Colorimetric RGB color space The short form allows the following ranges R 0 0 to 1 0 G 0 0 to 1 0 B 0 0 to 1 0 HP Color LaserJet 5 and 5M printers bypass the Colorimetric RGB process In place of it a device dependent RGB process is substituted with a Screen Match color table Using Color Modes Color LaserJet 5 5M DeskJet B 15 e Luminance Chrominance YUV Ec veW 0x04 YUV which is a linear transformation from SMPTE RGB is the default Luminance Chrominance color space The short form allows the following ranges Y 2 0 0 to 1 0 0 89 to 0 89 V 0 70 to 0 70 Note Luminance Chrominance color space support is at HP Color LaserJet level for HP Color LaserJet 5 and 5M printers Data Range Scaling White and black references define the encoding r
38. command is ignored for invalid configurations The Assign Color Index command actually applies this value and then resets it to 0 Assign Color Index This command assigns the three current color components to the specified palette index number Ec v l Index Number Default 0 Range Oto 2 1 where is the number of bits per index no assignment for out of range values This command resets the color components to 0 after assignment If the specified index number is greater than the palette size no index assignment is made but the three color components are set to 0 Using Palettes Color LaserJet 5 5M DeskJet C 21 C 22 Using Palettes Color LaserJet 5 5M DeskJet EN EN Modifying Output Color Color LaserJet 5 5M eskJet Introduction The previous appendices of this manual have been concerned with giving an overview of the color printing process choosing color modes and using palettes This portion of the manual explains how color can be modified to produce a desired result from using halftone render algorithms to change the way color is rendered to compensating for the yellow cast caused by a tungsten light source in a photograph The HP color printers can modify colors using the following means Halftone render algorithms provide a way to modify images based on a dither cell concept The algorithm chosen determines how specified colors are rendered as dots on the printed page Color
39. default palette A value field of 3 creates an 8 entry Device RGB palette compatible with a PCL Imaging Mode palette but not an HP GL 2 default IN palette A value field of 3 creates an 8 entry palette in Device CMY color space EN Using Color Modes 2 3 The Simple Color palettes are structured as follows Single Plane value 1 Index Color 0 White 1 Black 3 Plane RGB value 3 Index Color 0 Black 1 Red 2 Green 3 Yellow 4 Blue 5 Magenta 6 Cyan 7 White 3 Plane CMY value 3 Index Color 0 White 1 Cyan 2 Magenta 3 Blue 4 Yellow 5 Green 6 Red 7 Black 2 4 Using Color Modes EN PCL Imaging Mode EN The PCL Imaging mode entered using the Configure Image Data CID command Ec v W creates a variable sized programmable palette It provides multiple color spaces pixel encoding modes and reprogrammable palettes Configure Image Data CID Command The CID command provides configuration information for creating palettes and transmitting raster data The CID command performs the following Designates the color space for the newly created palette Designates the size of the palette Designates the Pixel Encoding Mode the format of the raster data Designates in certain circumstances the size in bits of the three components of the color specifications However this information is
40. having an associated color value and an associated width Pen colors are defined in terms of RGB components using the PC command Widths are established using the PW and WU commands A pen is selected with the SP command The maximum value for n is device dependent but is greater than or equal to the number of distinct colors the printer is able to produce If nis larger than that maximum the maximum sized palette is allocated If n 2 error 3 is set and the command is ignored The NP command defaults the palette size Receipt of this command does not default pen colors and or widths for existing pen values For example if the palette size is initially 8 and is decreased to 4 pen colors and widths for the new palette are retained from the colors and widths of the first 4 pens of the old palette If the palette size is increased from 8 to 16 the colors and widths for the first 8 pens remain the same and the colors and widths of the remaining pens are defaulted The pens are defaulted in accordance to how the palette was created either CID or Simple Color palettes Color Vector Graphics HP GL 2 7 17 If the currently selected pen is outside the range of the new palette size the SP command modulo function is applied to obtain a pen number which will index into the new palette this clears the current residue the unused portion of a pattern and terminates any sequence of continuous vectors For more information see the descripti
41. human eye a single bit is not sufficient Therefore the general form of a pixel is The number of components in the pixel which is generally either one or three and The number of bits per component 6 2 Raster Graphics EN EN This pixel format is sufficient to represent black and white images gray scale images and color images Furthermore this format can represent images where the color specification is directly in the image or where the pixel is an index into the palette The table below shows some possible combinations of the number of components and the bits per component Image Type Number of Bits per Components Component Black and White direct 1 1 Black and White indexed 1 1 Color indexed 1 Color direct 3 8 Raster Graphics 6 3 PCL 5 Color Raster Graphics The PCL 5 color raster graphics command set provides support for specifying an image s Dimensions Resolution Pixel format also known as the pixel encoding mode Compression mode Large image size is one of the major concerns with raster images For example the size of an 8 x 10 inch monochrome image at 150 dpi is 225 Kbytes The size of a 24 bit color image with the same size and resolution is 5 4 Mbytes If the color image is 600 dpi 24 bit color its size is 86 Mbytes Therefore the PCL 5 language supports several compressions modes that exploit redundancy between adjacent pixels or adjacent rows Further
42. in a device dependent space Byte 1 Pixel Encoding Mode Byte number 1 designates the format in which raster data is to be transmitted and interpreted The range of this value field is O to 3 All other values for this field are ignored Byte Value Pixel Encoding Mode Restrictions 0 Indexed by Plane Bits index must be default 1 2 3 4 5 6 7 or8 1 Indexed by Pixel Bits index must be 1 2 4 0r8 2 Direct by Plane 1 bit per primary RGB or CMY only 3 Direct by Pixel 8 bits per primary All Color Spaces B 8 Using Color Modes Color LaserJet 5 5M DeskJet EN Note EN You need one plane or one bit pixel for each power of two colors in the palette For example a 256 color palette requires 8 planes or 8 bits pixel 29 256 Direct pixel encoding modes 2 3 cannot be compressed using raster compression modes 1 or 2 Planar pixel encoding modes 0 2 cannot be compressed using raster compression mode 5 MODE 0 INDEXED BY PLANE In mode 0 default successive planes of data are sent for each raster row A plane contains one bit for each pixel in a row A pixel is not fully defined until it has received all the planes for that row The planes in a row form index numbers that define a pixel by selecting a palette entry Assuming 3 bits per index the underlined column of bits below is the palette index for pixel 3 of row 1 i1 is Isb i3 is msb Note that the Transfer Raster Data by
43. intersection device draws pixels centered at grid intersections see Figure 7 1 1 grid centered device draws pixels centered inside the boxes created by the grid see Figure 7 1 When the printer is set to grid centered mode mode 1 portions of a polygon that are zero height or zero width are not rendered When the printer is set to grid intersection mode mode 0 portions that are zero height or width are rendered as lines Portions that are both zero height and width are rendered as dots This command affects only HP GL 2 polygons it has no effect on characters rules or raster graphics This command can be invoked multiple times during a page it has no effect except to switch the model used for imaging This command is the HP GL 2 version of the PCL Pixel Placement command Whatever mode is selected using the HP GL 2 PP command also applies to PCL operation Likewise the PCL Pixel Placement command also affects HP GL 2 pixel placement Microsoft Windows fills polygons based on the grid centered method This command determines how pixels will be placed for both HP GL 2 and PCL operation The PP command is not defaulted by an IN command 7 22 Color Vector Graphics HP GL 2 EN Note EN Color Printing Overview Color LaserJet 5 5M eskJet Introduction This appendix provides an overview of the way color is used in the HP Color LaserJet Color LaserJet 5 5M DeskJet 1200C and DeskJet 1600C printers I
44. is received This command can be used to de select the active palette and select as the new active palette a palette created by the Palette Control command Ec amp p C For example to copy the active palette to an ID of 44 and select the new palette to use or modify send Fc amp p44i6c44S 3 6 Using Palettes EN EN When a palette creation command is received such as Configure Image Data Ec v W Simple Color Fc rtU or an HP GL 2 IN the created palette overwrites the active palette and is assigned the current palette select ID A palette popped from the stack overwrites the active palette and is assigned the current palette select ID EcE resets the palette select ID value to 0 and deletes all palettes in the palette stack and palette store including the active palette which is replaced by a default PCL fixed black and white palette with a palette ID of 0 Macros affect the palette select ID value as follows Calling or Overlaying a macro saves the ID value and a copy of the active palette Upon macro exit the restored palette again becomes the active palette with the restored ID An existing palette with this ID is deleted Executing a macro does not save the ID value or the active palette changes remain in effect Using Palettes 3 7 Palette Control ID The Palette Control ID command specifies the ID number to be used by the Palette Control Command Ec amp p l Palette ID number Default 0 Ra
45. monitor on which the page was designed will show an exact match However true color matching is only satisfactory when using the monitor as a viewing reference Viewed away from the screen the printed page may appear flat and unsaturated because printers and monitors have different dynamic ranges For example black on the screen appears gray when compared to printed black which is unacceptable if the intent is pure black Likewise the white produced on a monitor screen appears yellow or blue when compared to a white sheet of paper True color matching would require that gray be printed in the black areas and colored dots be printed in the white areas Color Printing Overview Color LaserJet 5 5M DeskJet A 11 Color Appearance Matching Color appearance matching goes beyond true color matching by including adjustments for the dynamic ranges of the devices so the user s intent is maintained For example the white areas of a page shown on a monitor display screen would be printed as white on a printed page because the user specified white even though the screen cannot duplicate a white that truly matches white paper Although the printed color does not exactly match screen color color appearance does match which is what users usually want To maximize user satisfaction the PCL language uses appearance matching when rendering device independent color Color Lookup Tables Color lookup tables which provide additional control of the p
46. palette by specifying an ID number The previously active palette is unchanged Ec amp p S Palette ID number Default 0 Range 0 to 32767 command is ignored for out of range values This command activates the designated palette in the palette store The command is ignored if the specified ID matches the active palette s ID or if no palette with that ID exists The designated ID is saved as the palette select ID in the current modified print environment C 6 Using Palettes Color LaserJet 5 5M DeskJet EN EN This command can be used to de select the active palette and select as the new active palette a palette created by the Palette Control command Ec amp p C For example to copy the active palette to an ID of 44 and select the new palette to use or modify send Fc amp p44i6c44S When a palette creation command is received such as Configure Image Data Ec v W Simple Color Fc rtU or an HP GL 2 IN the created palette overwrites the active palette and is assigned the current palette select ID which is unchanged A palette popped from the stack overwrites the active palette and is assigned the current palette select ID which is unchanged EcE resets the palette select ID value to 0 and deletes all palettes in the palette stack and palette store including the active palette which is replaced by a default PCL fixed black and white palette with a palette select ID value of 0 Macros affect the palette select ID
47. palette deleted 1 Delete all palettes in the stack active palette is not affected 2 Delete palette specified by Palette Control ID 6 Copy active palette to ID specified by Palette Control ID Default 0 Range 0 1 2 6 command is ignored for unsupported values A value of 0 deletes all palettes except those on the palette stack The active palette is replaced by the default black and white palette ID 0 The palette control ID is not used A value of 1 clears the palette stack The active palette is unaffected and the palette control ID is not used A value of 2 deletes the palette with the specified palette control ID if it exists otherwise the command is ignored For example to delete palette 53 send c amp p53i2C If the active palette s ID is specified the active palette is replaced by the default black and white palette This option does not change the palette control ID value When the active palette is replaced by the default black and white palette the graphics state associated with the previous palette is also replaced A value of 6 creates a copy of the active palette The copy receives the ID specified by the last Palette Control ID command For example to copy the active palette to a palette with an ID of 14 send Fc amp p14i6C The copied palette overwrites any palette that already has an ID equal to the palette control ID The copied palette does not become the active palette The command is ignore
48. primary Isw 41 42 Gain for red primary msw 43 44 Gain for red primary Isw 45 46 Gamma for green primary msw 47 48 Gamma for green primary Isw 49 50 Gain for green primary msw 51 52 Gain for green primary Isw 53 54 Gamma for blue primary msw 55 56 Gamma for blue primary Isw 57 58 Gain for blue primary msw 59 60 Gain for blue primary Isw 61 62 Minimum red value msw 63 64 Minimum red value Isw 65 66 Maximum red value msw 67 68 Maximum red value Isw 69 70 Minimum green value msw 71 72 Minimum green value Isw 73 74 Maximum green value msw 75 Using Color Modes Color LaserJet 5 5M DeskJet B 21 Note Byte 15 msb 8 7 Isb 0 Byte 76 Maximum green value Isw 77 78 Minimum blue value msw 79 80 Minimum blue value Isw 81 82 Maximum blue value msw 83 84 Maximum blue value Isw 85 HP Color LaserJet 5 and 5M printers bypass the Colorimetric RGB process In place of it a device dependent RGB process is substituted with a Screen Match color table Luminance Chrominance Long Form The long form for Luminance Chrominance allows color spaces other than the default YUV such as Kodak Photo YCC the proposed JPEG and TIFF 6 0 YCrCb standard YES and YIQ These Luminance Chrominance color spaces are derived from the Colorimetric RGB space using a 3x3 transformation matrix The tristimulus luminance y value of the white point is assumed to be 10096 and
49. printer In raster mode indexed color selection uses the palette but direct selection does not Default palettes are created by all the PCL color modes Black and White Simple Color PCL Imaging and HP GL 2 Imaging The active palette may be modified when in the PCL Imaging or HP GL 2 imaging modes but not when in the Simple Color or Black and White modes When switching between PCL 5 and HP GL 2 contexts the active palette is automatically transferred Multiple palettes can exist in the system via the Palette ID and Palette Stack mechanism However only one palette at a time can be active A palette created in the PCL context remains active and unchanged when switching to the HP GL 2 context and a palette created in the HP GL 2 context remains active and unchanged when switching to the PCL context Performing a reset or entering PJL overwrites the active palette with the default black and white palette Whenever a new palette is created the currently or previously active palette is destroyed A new palette is created by power on and also by the following commands PCL Reset EcE Simple Color Ec r U Configure Image Data Ec vstW e HP GL 2 Initialize IN The active palette can be saved by pushing it onto the palette stack with the Push Pop Palette command Popping a palette from the stack destroys the active palette the popped palette becomes the active palette C 2 Using Palettes Color LaserJet 5
50. row A raster row must be compressed using only one method The cursor position is updated with each row of the raster block The cursor position is also incremented when a block count of less than 3 is sent A Raster Y Offset command moves the entire block of raster data and initializes the seed row to zeros The seed row is set to zero even if the y offset is zero Block size takes precedence over row length If the row length of any line exceeds the block size the row length is truncated to the block size Forduplicate and empty rows a row length value of zero does not update the cursor however the seed row is initialized to zero f an unsupported command byte for a raster row is encountered the remaining bytes for the block are skipped the seed row is cleared and the cursor is not incremented For method 1 run length encoded if the row length is odd the cursor is incremented the row data is skipped thrown away and the seed row is left unchanged For method 1 a row length value of zero increments the cursor and zero fills the seed row For method 2 TIFF if row length terminates the data before the control byte value is satisfied literal byte count greater than row length the data following the control byte if any is printed as text The cursor is incremented For Method 2 if row length is equal to one the one byte is consumed from the I O and the cursor is incremented The data is igno
51. set the raster width and height is printed Data outside the intersection is clipped Upon receiving an End Raster Graphics Fc rC command the cursor position is set to the left graphics margin of the next raster row after the raster height boundary Portrait Mode 0 amp 3 Landscape Mode 0 Print Direction 0 180 Landscape Mode 3 Raster height Logical Page Raster height Raster height height of width of Logical Page Logical Page Landscape Portrait Mode 0 Mode 0 Print Direction Print Direction 90 270 90 270 Figure 6 5 Maximum Raster Height 6 14 Raster Graphics EN Source Raster Width Command Note Note Note EN The Raster Width command specifies the width in pixels of the raster area Width is in the direction that the raster rows are laid down hence width is subject to the current raster presentation mode and print direction see Figure 6 6 Ec r S Width in pixels of the specified resolution Default depends on raster presentation mode when presentation mode is 0 then width width of logical page minus left graphics margin when presentation mode is 3 then width dimension of logical page along paper length minus left graphics margin Range Oto logical page width minus left graphics margin Greater values default to the logical page width left graphics margin Specifying the raster width and raster height improves memory usage Therefore it is highly recommended
52. the CR command is not supported by the HP Color LaserJet 4500 or 8500 printers In general when using HP GL 2 on the HP Color LaserJet family and DeskJet 1200C and 1600C color printers keep in mind that Palette information stays the same when switching between PCL 5 and HP GL 2 The HP GL 2 Initialize IN command sets the palette to the default eight pen palette and also resets the ROP code see the MC command section later in this chapter and the pixel placement command As with color plotters to specify a particular color you use the SP Select Pen command If you are not familiar with using HP GL 2 see the PCL 5 Printer Language Technical Reference Manual Color Vector Graphics HP GL 2 7 1 Enter HP GL 2 Mode This command causes the printer to interpret subsequent commands as HP GL 2 commands instead of PCL printer language commands Ec B 1 0 Default Range Stand alone plotter mode single context Position pen at previous HP GL 2 pen position Position pen at current PCL cursor position Use current PCL coordinate system and previous HP GL 2 pen position Use PCL dot coordinate system and the current PCL CAP 0 1 to 3 unsupported negative values default to 1 all other unsupported values are ignored As soon as the printer receives this command it switches to HP GL 2 mode interpreting commands as HP GL 2 commands until it receives an Enter PCL Mode or
53. the color space as well as the values used to describe a given color Black in the RGB color space is described using the three numbers 0 0 0 but in the CMY color space it is described as 100 100 100 where the values are percentages of each color Color Management and the Standard Red Green Blue Color Space For color to be reproduced in a predictable manner across different devices and materials it has to be described in a way that is independent of the specific mechanisms and materials used to produce it For instance color displays and color printers use very different mechanisms for producing color Traditionally operating systems have supported color by declaring support for a particular color space RGB in most cases However since the interpretation of RGB values varies between devices color was not reliably reproduced across different devices The needs of the very high end publishing sector could not be met by the traditional means of color support so the various computer operating systems added support for using International Color Consortium ICC profiles to characterize device dependent colors in a device independent way They used the profiles of the input device that created an image and the output device that displayed or printed the image to create a transform that moved the image from the color space of the input device to that of the output device This resulted in very accurate color and access to the enti
54. the following values Byte 0 Format 0 00 hex Byte 1 Continuation 0 00 hex Byte 2 Pixel Encoding 1 01 hex Byte 3 Reserved 0 00 hex Byte 4 5 Height in Pixels 0 16 00 10 hex Byte 6 7 Width in Pixels 0 32 00 20 hex Byte 8 Begins the first bytes of binary data The PCL code below downloads the user defined pattern and assigns it an ID number of 3 1 Specify the pattern ID number Ec c3G Assigns an ID number of 3 to the pattern data which follows 2 Send the User defined Pattern command Ec c72W Specifies that 72 bytes are to follow 8 bytes for the header plus 64 bytes of pattern data The PCL Print Model 5 41 Send the pattern header and binary data 00 1F OF 07 03 01 00 00 00 00 00 00 00 00 00 FF ER BE FF EE FF EE FF lF OF 07 03 01 01 FF FF FF EF FF EF FF EF EE FE EG F8 FO EO CO 80 00 00 10 00 20 FF FE EG F8 FO EO CO 80 00 00 00 00 00 00 00 00 Note There must be an even number of bytes in user defined pattern data hence the trailing zeros padding in the last eight data rows above In the previous example the raster data code is presented in hexadecimal however the numbers in the escape sequences are decimal 5 42 The PCL Print Model EN Set Pattern Reference Point Command Note EN The Set Pattern Reference Point command causes the printer
55. the lower left corner of the PCL Picture Frame 0 0 1 This parameter option 1 specifies that the pen position and the label carriage return point become the same as the current PCL cursor position 2 2 transfers the current PCL dot coordinate system to HP GL 2 including the PCL origin and axes but uses the previous HP GL 2 pen position as the new pen position Once the PCL coordinate system is established with this command itis independent of the P1 and P2 positions 3 This parameter option Fc963B specifies that the pen position and the label carriage return point become the same as the current PCL cursor position The current PCL dot coordinate system and axes are also transferred to HP GL 2 once the PCL coordinate system is established with this command it is independent of the P1 and P2 positions When HP GL 2 is entered using any dual context mode any variation of the command except Fc95 1B the HP GL 2 and PCL contexts can be merged resulting in the following HP GL 2 and PCL data can be combined on the same page HP GL 2 graphics can be integrated directly with text The size and location of the PCL picture frame can be specified HP GL 2 graphics can be scaled to fit within the picture frame Color Vector Graphics HP GL 2 7 3 The PCL palette and color configuration are transferred between contexts The current logical operation and pixel placement settings are transferred bet
56. to plane and is independent of raster width Planes shorter than the raster width are zero filled Empty planes can be sent using Fc bOV For monochrome printers zero indicates a white pixel For color printers the color indicated by zero depends on the current palette Transfer Raster Data By Row Block Command The Transfer Raster Data command is used to transfer a row of raster data to the printer This command is used for sending all raster graphics data to monochrome printers It is also used for color printers when encoding the raster data by pixel rather than by plane When encoding color raster data by plane this command is used for single plane rows or for the last plane in a multi plane row since this command advances the cursor position to the beginning of the next raster row Ec b W raster data Default N A Range 0 to 32767 Raster Graphics 6 33 Note The value field identifies the number of bytes in the raster row These bytes are interpreted as one row of raster graphics data printed at the current Y position at the left raster graphics margin Upon completion of this command the cursor position is at the beginning of the next raster row at the left raster graphics margin Raster graphics are independent of the text area and perforation skip mode these boundaries are ignored Raster graphic images raster height and raster width are limited to the printable area images that extend beyond the printable
57. user defined dither will not take effect until after explicitly selecting it via a render algorithm command with a value of 9 or 10 However if the current render algorithm or last render algorithm received was a user defined algorithm value 9 or 10 then a user defined matrix will take effect as soon as it is downloaded In this case another render algorithm command value 9 or 10 is not needed to select the downloaded user defined dither matrix This is due to the fact that the downloaded user defined dither algorithm is the currently selected render algorithm If the command is sent before downloading a user defined dither matrix the device will use the device s user defined dither default if available or if no default is available will use the default render algorithm Note The user defined dither matrix must be defined for processing with additive colors RGB Since user defined algorithms cannot be used when a device independent color space is active trying to specify a user defined algorithm in this situation causes the default algorithm to be used The default is used until the algorithm is changed to something other than user defined or until you specify a device dependent color space The table below shows the format for a dither matrix that is applied to all three color primaries The format for multiple dither matrices is supplied after this explanation uint 16 means unsigned 16 bit integer ubyte means u
58. will be redundant and therefore compressible from row to row The remaining pixel encoding modes index by plane index by pixel and direct by plane can be redundant within a row and are therefore compressed well by compression methods such as run length encoding and TIFF rev 4 0 6 20 Raster Graphics EN EN The Set Compression Mode command has the following form Ec b M 0 Unencoded 1 Rundength encoding 2 Tagged Imaged File Format TIFF rev 4 0 3 Delta row compression 5 Adaptive compression Default 0 Range 0 3 5 other values are ignored Unencoded Method 0 This is a simple transfer of binary data without any compression Run length Encoding Method 1 Run length encoding interprets raster data in pairs of bytes The first byte of each pair is the repetition count for the data in the second byte The second byte is the raster data to be printed A repetition count of 0 signifies the pattern in the data byte is not repeated it occurs only once A repetition count of 1 signifies the pattern occurs twice The repetition count can range from 0 to 255 for a repetition of 1 to 256 times Repetition count byte 0 255 pattern byte Tagged Image File Format Encoding Method 2 Tagged Image File Format encoding interprets raster data as TIFF Packbits This format combines features of methods 0 and 1 A control byte precedes the raster data pattern bytes The control byte identi
59. with it Simple Color Mode provides a palette of fully saturated colors whose colors are similar to those of a plotter s pen colors The palette is nonprogrammable and is intended for simple printing of items such as bar and pie charts For applications requiring different or more specific colors the printer offers the PCL Imaging and HP GL 2 Imaging Modes The palette colors in these two modes can be modified to provide the desired result When choosing color for a particular application the Color LaserJet printer provides device dependent and device independent color the DeskJet 1200C and 1600C support only device dependent color Device independent color provides accurate color matching based on an absolute color standard It is preferred when users want a precise color to match the output from another device or to match the color on an existing page Besides providing device independent color for precise color matching the HP printers can modify color to compensate for various characteristics The Color LaserJet printer supports the following methods of modifying color the DeskJet 1200C and 1600C printers support halftone algorithms and gamma correction but not color lookup tables or the Viewing Illuminant command Halftone render algorithms determine how colors are rendered using the printers available colors Halftone algorithms can be used to change apparent resolution change the texture of images reduce the number of colors
60. x07 x07 x07 x07 x07 x07 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 xO 0 x00 x00 x00 x00 x00 x00 x00 x01 x01 x01 x01 x01 x01 x01 x01 x01 x 01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x0 3 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x 04 x04 x04 x04 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x07 x07 x07 x07 x07 x07 x0 7 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x00 x00 x00 x 00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x0 2 x02 x02 x02 x02 x02 x02 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x 03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 e b3 M e b0W e bOW e b0 W e b0W e bOW e b0W e bOW e b0W e b0W e b OW e b0W e b0W Ve bOW e b0W e b0W e b0W e bOW e bOW e b0W e b0 W e b0W e b0
61. 00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x 00 x00 x00 x00 x00 x00 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x03 x03 x03 x03 x0 3 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x04 x 04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x0 6 x06 x06 x06 x06 x06 x06 x06 x06 x07 x07 x07 x07 x07 x07 x07 x07 Nx 07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x00 x00 x00 x00 x00 V x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 x00 V x00 x00 x00 x00 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x01 x0 1 x01 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x02 x 02 x02 x02 x02 x02 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x03 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x04 x05 x05 x05 x05 x05 x0 5 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x05 x06 x06 x 06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x06 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07 x07
62. 1 4 Start Raster Graphics command 6 17 T Tagged Image File Format TIFF Encoding raster compression 6 21 texture 5 2 TIFF adaptive compression 6 29 6 31 raster graphics compression 6 20 Transfer Raster Data command 6 28 6 32 6 33 transparency interactions and logical operation 5 12 transparency mode 5 2 rectangular area 5 49 source 5 7 U unencoded adaptive compression 6 29 user defined dithers D 6 user defined pattern assign ID 5 29 base pattern 5 33 data 5 38 5 39 define pattern command 5 38 deleting 5 44 descriptor format header 5 38 example 5 40 header fields 5 38 introduction 5 33 Pattern Control command 5 44 permanent 5 44 reference point 5 36 selecting ID 5 29 Set Pattern Reference Point command 5 43 temporary 5 44 tiling 5 34 User Defined Pattern command 5 38 EN user defined patterns 5 33 V Vertical Rectangle Size command decipoints 5 47 PCL Units 5 47 viewing illuminant A 2 viewing illuminant command D 18 W well behaved raster 1 9 white rule 5 32 width pixel user defined pattern descriptor 5 39 Y Y offset command 6 19 Y offset adaptive compression 6 31 Z zeroed rows in raster graphics 6 5 Index 5 Index 6 EN ocoao Copyright 1999 Printed on Hewlett Packard Co Recycled Paper Printed in USA
63. 11062860010010111 Relative Offset of 31 Means Next Byte is Offset Too Final Offset Byte Adds 128 Bytes 31 255 128 414 Bytes Additional 255 Byte Offset Means Next Byte is Offset Too The total offset is 414 which is the sum of the three offset values 31 255 128 Seed Row The seed row is basically the current raster data row the row being printed It is maintained by the printer for use by delta row compression The delta compression replacement bytes are applied to the seed row to create the new row This new data row is printed and becomes the new seed row For color raster images the printer operates on each plane independently and a separate seed plane is maintained for each graphic plane A Y offset however affects all planes and seed rows simultaneously 6 26 Raster Graphics EN Note EN The seed row is updated by every raster graphic transfer regardless of the compression method This allows the delta compression method to be mixed with other methods to achieve better compression performance Repeating a Row Ec boW When using the delta compression method it is possible to repeat or copy the previous raster row using the Raster Data Transfer command This is accomplished by setting the Raster Data Transfer command value field to zero Printing A Zeroed Row Setting the Seed Row to Zero Ec b 1 Y It is possible to print a row of all zeros using the Raster Y Offset command Sending a Raster
64. 141 SDTSxoxn 115 SDTnoan 142 SSDxTDxax 116 DSTDxox 143 TDSanan 117 DSTnoan 144 TDSxna 118 SDTSnaox 145 SDTSnoaxn 119 DSan 146 DTSDToaxx 120 TDSax 147 STDaxn 121 DSTDSoaxxn 148 TSDTSoaxx 122 DTSDnoax 149 DTSaxn 123 SDTxnan 150 DTSxx 124 STDSnoax 151 TSDTSonoxx 125 DTSxnan 152 SDTSonoxn 126 STxDSxo 153 DSxn 127 DTSaan 154 DTSnax 128 DTSaa 155 SDTSoaxn 129 STxDSxon 156 STDnax 130 DTSxna 157 DSTDoaxn 131 STDSnoaxn 158 DSTDSaoxx 132 SDTxna 159 TDSxan 133 TDSTnoaxn 160 DTa 134 DSTDSoaxx 161 TDSTnaoxn The PCL Print Model 5 21 Table 5 4 Logical Operations ROP3 continued Boolean Boolean Input Value Function Input Value Function 162 DTSnoa 189 SDxTDxan 163 DTSDxoxn 190 DTSxo 164 TDSTonoxn 191 DTSano 165 TDxn 192 TSa 166 DSTnax 193 STDSnaoxn 167 TDSToaxn 194 STDSonoxn 168 DTSoa 195 TSxn 169 DTSoxn 196 STDnoa 170 D 197 STDSxoxn 171 DTSono 198 SDTnax 172 STDSxax 199 TSDToaxn 173 DTSDaoxn 200 SDToa 174 DSTnao 201 STDoxn 175 DTno 202 DTSDxax 176 TDSnoa 203 STDSaoxn 177 TDSTxoxn 204 S 178 SSTxDSxox 205 SDTono 179 SDTanan 206 SDTnao 180 TSDnax 207 STno 181 DTSDoaxn 208 TSDnoa 182 DTSDTaoxx 209 TSDTxoxn 183 SDTxan 210 TDSnax 184 TSDTxax 211 STDSoaxn 185 DSTDaoxn 212 SSTxTDxax 186 DTSnao 213 DTSanan 187 DSno 214 TSDTSaoxx 188 STDSanax 215 DTSxan 5 22 The PCL Print Model Table 5 4 Logical Operations ROP3 co
65. 4 0 31 0 60 0 16 0 07 0 3127 0 3290 2 2 1 0 2 2 1 0 RGB direct 8 bits primary RGB direct 8 bits primary Chromaticity coordinates for RGB amp White Point Gamma and gain for RGB Data range encoding Non Linear Sony Trinitron SHORT FORM Not Applicable B 26 Using Color Modes Color LaserJet 5 5M DeskJet EN LONG FORM CID 2 3 0 8 8 8 0 62 0 34 0 30 0 58 0 15 0 09 0 2800 0 2933 2 3 1 19 2 3 1 19 2 3 1 19 0 0 255 0 0 0 255 0 0 0 255 0 RGB direct 8 bits primary Chromaticity coordinates for RGB White Point Gamma and gain for RGB Data range encoding YUV Chrominance Luminance Color Space SHORT FORM CID 4 3 0 8 8 8 YUV direct 8 bits primary YUV Chrominance Luminance with Sony Trinitron LONG FORM CID 2 3 0 8 8 8 0 30 0 59 0 11 0 30 0 59 0 89 0 70 0 59 0 11 0 0 255 0 227 0 227 0 179 0 179 0 0 62 0 34 0 30 0 58 0 15 0 09 0 2800 0 2933 2 3 1 19 2 3 1 19 2 3 1 19 YUV direct 8 bits primary 3x3 YUV matrix Data encoding Chromaticity coordinates chromaticity white point Gamma and gain for RGB EN Using Color Modes Color LaserJet 5 5M DeskJet B 27 HP GL 2 Imaging Mode The HP GL 2 Imaging Mode provides a way of using vector commands in printing documents Although the default PCL and HP GL 2 palettes are not the same when transferrin
66. 5M DeskJet EN Saving the Palette EN The current palette is destroyed when a new palette is created The Push Pop Palette command can save push the current palette and then restore pop it Push Pop Palette Command This command pushes or pops the palette from the palette stack Ec p P 0 Push save palette 1 Pop restore palette Default 0 Range 0 1 invalid values are ignored A value of 0 Ec pOP pushes a copy of the active palette onto the palette stack When a palette is pushed the active palette is not affected A value of 1 Ec p1P pops the most recently pushed palette and destroys the active palette the popped palette becomes the active palette As with any stack the last item pushed is the first item popped Pushing a palette saves the following parameters Color definitions for each palette entry Pen widths for HP GL 2 use Color space specification Black and white references Number of bits per index Pixel encoding mode Number of bits per primary Gamma correction Viewing illuminant Color lookup tables Render algorithm Downloaded dither matrix Using Palettes Color LaserJet 5 5M DeskJet C 3 Pushing a palette does not save the following parameters Foreground color Color components 1st 2nd and 3rd Finish mode Monochrome print mode The palette stack depth is limited by printer memory Attempts to push a palette with insu
67. D if it exists otherwise the command is ignored For example to delete palette 53 send Fc amp p53i2C If the active palette s ID is specified the active palette is replaced by the default black and white palette This option does not change the palette control ID value When the active palette is replaced by the default black and white palette the graphics state associated with the previous palette is also replaced A value of 6 creates a copy of the active palette The copy receives the ID specified by the last Palette Control ID command For example to copy the active palette to a palette with an ID of 14 send Fc amp p14i6C The copied palette overwrites any palette that already has an ID equal to the palette control ID The copied palette does not become the active palette The command is ignored if a palette is to be copied to its own ID Using Palettes 3 9 The Palette Control command provides a way of managing system memory by deleting palettes in either the stack or store that are no longer in use Palette Control that is exercised during macros can have significant impact on palettes that exist within the system Deleting all palettes or those on the stack or the current palette or all those except on the stack can have adverse effects when the macro is exited The adverse effect could be the deletion of the desired palette and replacement with a black and white non programmable palette 3 10 Using Palettes EN Simple C
68. Ec b4W 255 255 255 192 24 00000000 00000000 11111111 10000000 Fc b4W 0 0 255 128 25 00000000 00000000 11111111 00000000 Fc b4W 0 0 255 0 26 00000000 00000000 11111110 00000000 Fc b4W 0 0 254 0 27 00000000 00000000 11111100 00000000 Fc b4W 0 0 252 0 28 00000000 00000000 11111000 00000000 Fc b4W 0 0 248 0 29 00000000 00000000 11110000 00000000 Fc b4W 0 0 240 0 30 00000000 00000000 11100000 00000000 EFc b4W 0 0 224 0 31 00000000 00000000 11000000 00000000 Fc b4W 0 0 192 0 32 00000000 00000000 10000000 00000000 Fc b4W 0 0 128 0 The brackets and commas are not part of the raster data command they are used only to delineate the data 6 40 Raster Graphics EN 300 400 Figure 6 7 Example of Raster Graphic Image Data EN Raster Graphics 6 41 Color Raster Graphics Example This example demonstrates the Indexed by Pixel PEM of the CID command It produces a one inch wide by one half inch high image of one inch high by 0 1 inch wide colored vertical bars The pixels in the image are eight byte indices repeatedly ranging from 0 to 7 thus giving the different colored vertical bars The PCL commands are decoded as follows PCL Command ESC E Description Reset Command Arguments lt ESC gt v6W x00 x01 x08 x 08 x08 x08 Configure Image Data Color space device RGB Pixel Encoding Mode indexed by pixel Bits Index 8 Bits Primary 1 8 Pits Primary
69. Imaging The active palette may be modified when in the PCL Imaging or HP GL 2 imaging modes but not when in the Simple Color or Black and White modes When switching between PCL 5 and HP GL 2 contexts the active palette is automatically transferred Multiple palettes can exist in the system via the Palette ID and Palette Stack mechanism However only one palette at a time can be active A palette created in the PCL context remains active and unchanged when switching to the HP GL 2 context and a palette created in the HP GL 2 context remains active and unchanged when switching to the PCL context Performing a reset or entering PJL overwrites the active palette with the default black and white palette Whenever a new palette is created the currently or previously active palette is destroyed A new palette is created by power on and also by the following commands PCL Reset EcE Simple Color Ec r U Configure Image Data Ec vstW e HP GL 2 Initialize IN The active palette can be saved by pushing it onto the palette stack with the Push Pop Palette command Popping a palette from the stack destroys the active palette the popped palette becomes the active palette 3 2 Using Palettes EN Saving the Palette EN The current palette is destroyed when a new palette is created The Push Pop Palette command can save push the current palette and then restore pop it Push Pop Palette Command T
70. L to HP GL 2 active palette information does stay the same You can switch between PCL and HP GL 2 and use the same palette and you can also modify palettes using either PCL or HP GL 2 Compared to monochrome printers the HP Color LaserJet printer family DeskJet 1200C and 1600C color printers have some commands that are new and or modified for use with color printers Chapter 7 describes the new or modified HP GL 2 commands If you are not familiar with using HP GL 2 see the PCL 5 Printer Language Technical Reference Manual It provides a detailed explanation of using HP GL 2 Using Color Modes 2 13 2 14 Using Color Modes EN EN 3 Using Palettes Introduction A palette is a collection of color specifications selected using index numbers The figure below illustrates a palette Each palette entry associates an index number with three primary color components For HP GL 2 purposes only a pen width is also associated with each palette entry Color Palette HP GL 2 Primary 1 Primary 2 Primary Pen Width 0 1 2 3 4 5 6 7 8 9 n max 255 Bits per Primary e Primary 1 8 2 8 e Primary 32 8 Using Palettes 3 1 In non raster mode the current palette contains all the available colors In raster mode indexed color selection uses the palette but direct selection does not Default palettes are created by all the PCL color modes Black and White Simple Color PCL Imaging and HP GL 2
71. LA oca PCL 5 Color Technical Reference Manual PCL 5 Color Technical Heference Manual 7 gt Notice The information contained in this document is subject to change without notice Hewlett Packard Company 11311 Chinden Boulevard Boise Idaho 83714 U S A Copyright and License Copyright 1999 Hewlett Packard Company All rights are reserved This document contains proprietary information which is protected by copyright Except as allowed by copyright laws or herein reproduction adaptation or translation without prior written permission is prohibited Trademarks Adobe PostScript and the PostScript logo are trademarks of Adobe Systems Incorporated which may be registered in certain jurisdictions AppleTalk is a registered trademark of Apple Computer Inc PCL and Resolution Enhancement are registered trademarks of Hewlett Packard Company BM is a registered trademark of International Business Machines Corporation Inside This Manual Note What You Can Learn From This Manual This manual describes the PCL 5 commands used to print color on the HP Color LaserJet printer family and the other Hewlett Packard PCL 5 color printers Some of the main topics include an overview of the color printing process using palettes choosing color modes adjusting output color to meet your requirements printing color raster graphics and HP GL 2 vector graphics Examples are provided wh
72. OXEE 102 0x66 EN Color Vector Graphics HP GL 2 7 7 Note When using the MC command some pattern types will not produce the expected ROP result This only occurs when using the FT Fill Type command pattern types 1 2 3 and 4 and when the ROP includes an XOR operation This problem is due to the fact that these patterns are the result of a vector operation and do not produce raster data for use by a ROP operation All other Fill Type command patterns types 10 11 21 or 22 operate as expected The MC command supports all 255 Microsoft Windows ROPS which are listed on the following page in reverse polish notation RPN using the abbreviation listed above D for Destination S for Source etc Note See Logical Operation Command in Chapter 5 for usage and ROP selection information 7 8 Color Vector Graphics HP GL 2 EN Table 7 1 Logical Operations ROP3 Boolean Boolean Input Value Function Input Value Function 0 0 27 SDTSxaxn 1 DTSoon 28 TSDTaox 2 DTSona 29 DSTDxaxn 3 TSon 30 TDSox 4 SDTona 31 TDSoan 5 DTon 32 DTSnaa 6 TDSxnon 33 SDTxon 7 TDSaon 34 DSna 8 SDTnaa 35 STDnaon 9 TDSxon 36 STxDSxa 10 DTna 37 TDSTanaxn 11 TSDnaon 38 SDTSaox 12 STna 39 SDTSxnox 13 TDSnaon 40 DTSxa 14 TDSonon 41 TSDTSaoxxn 15 Tn 42 DTSana 16 TDSona 43 SSTxTDxaxn 17 DSon 44 STDSoax 18 SDTxnon 45 TSDnox 19 SDTaon 46 TSDTxox 20 DTS
73. Plane command Ec b V is used for all planes except the last plane of each row which uses the Transfer Raster Data by Row command Fc bstW Ec bEV 1 plane 1 1 d i it i Ec b V plane 2 i2 i2 i2 i2 i2 Ec b W plane 3 ia i3 i3 Ec b V row2 plane 1 1 Hd Hd d id Using Color Modes Color LaserJet 5 5M DeskJet B 9 Example Ec v6W 00 00 03 08 08 08 Binary data for CID represented in hex Sets color space to RGB pixel encoding mode to 0 palette size to 8 8 planes last 3 bytes ignored EC r1A Start raster Ec b1V10110000 Transfer plane 1 the first bit for each pixel in the first row Combining each bit with its corresponding bit in the other planes forms the palette index number for that pixel Ec b1V01110000 Transfer plane 2 the second bit for each pixel in the row Ec b1W10101000 Transfer plane 3 the third bit for each pixel in the row and move to the next row Note that the Ec b W command is used to send the last plane of each row MODE 1 INDEXED BY PIXEL In mode 1 each pixel in a row is fully specified before any bits are sent for the next pixel The bits for each pixel form a palette index number Assuming 4 bits per index the underlined block below is the palette index for pixel 2 of row 1 i1 is Isb Ec b W 1 i4 i3 i2 11 14 i3 12 i Ec b W W row2 14 1 12 11 14 1 12 it Ec b amp W row3 14 1 12 11 14 1 12 11 B 10 Using Color Modes Color La
74. Printing Overview Color LaserJet 5 5M DeskJet EN EN Using Color Modes Color LaserJet 5 5M eskJet This appendix describes how color commands were supported on the following printers HP Color LaserJet Color LaserJet 5 5M HP DeskJet 1200C and 1600C Since then the PCL 5 color command set has been simplified as described in Chapter 1 Appendices A through D and Chapters 5 through 7 describe the color commands as they were supported for these printers Using Color Modes Color LaserJet 5 5M DeskJet B 1 Introduction The PCL printer language has four color modes Black and White Simple Color PCL Imaging HP GL 2 Imaging PCL allows you to use any mode or combination of modes to accomplish your printing objectives most efficiently All four of the color modes create a palette The palette for each mode is discussed in the section describing that mode and also in Appendix C Using Palettes Black and White Mode Default Black and White Mode is the default color mode PCL devices power up in this mode and revert back to it whenever the printer receives an ECE reset Black and White mode is also selectable using the Simple Color command Ec r1U This mode creates an unmodifiable default 2 pen palette with white at index 0 and black at index 1 compatible with existing monochrome PCL 5 printers Simple Color Mode Simple Color Mode entered by the Simple Color command amp c r U cre
75. Ps from ROP 0 to ROP 255 where each operation is defined as a logic equation This table can be difficult to understand and use Furthermore it does not show the differences that depend on the color space A truth table is an alternative method for understanding the results of a logical operation When used with ROPs for finding the resulting destination value it is more easily understood than the logic operation ROP agp 252 11111100 T exture S ource D estination D estination 1 1 1 1 1 1 0 1 1 0 1 1 1 0 0 1 0 1 1 1 0 1 0 1 0 0 1 0 0 0 The first destination column is ignored and the second destination column is the result of the ROP White 1 1 1 and Black 0 0 0 EN The PCL Print Model 5 13 For example the logic equation for ROP 252 in the RGB color space is T OR S which is shown as TSo in Table 5 4 The truth table for the ROP is shown above and can be seen to correspond to the logic equation TSo that is D gets the value of T OR S without regard to the current value of D Furthermore the binary value of 252 is 11111100 and corresponds with the value of the D for all the combinations of T and S when the truth table starts with 1 1 1 and ends with 0 0 0 It s possible to derive the logical operation for a truth table and to create a truth table for a logical operation However the most important point is that the binary value of the ROPs number gives th
76. This command allows you to implicitly tell the printer to pad raster rows that are not specified for the full raster width with zeros Unspecified data maps to either white or transparent depending on the source transparency mode this is true only if index 0 is white For color printers a zero fill is not necessarily white When a Transfer Raster Data command is received that specifies a row of data that is longer than the raster width the data that extends beyond the raster width is clipped This command is ignored after the Start Raster Graphics or Transfer Raster Data commands until the next End Raster Graphics command Only raster data appearing within the intersection of the logical page the printable area and if set the raster width and height is printed Data outside the intersection is clipped Raster Graphics 6 15 Portrait Mode O amp 3 Print Direction 90 270 Landscape Mode O Print Direction O 180 Landscape Mode 3 Raster width width of Logical Page Raster width Raster width height of width of Logical Page Logical Page Portrait Mode O Print Direction 90 270 Figure 6 6 Maximum Raster Width 6 16 Raster Graphics EN Start Raster Graphics Command EN The Start Raster Graphics command identifies the beginning of the raster data and also specifies the left graphics margin Ec r A 0 Start graphics at default left graphics margin X position 0 1 Start graphics
77. Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOWNe bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOWNe bOWe bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e rC 6 44 Raster Graphics EN Color Vector Graphics HP GL 2 Introduction The process involved in using HP GL 2 with the HP Color LaserJet family or DeskJet 1200C and 1600C color printers is nearly identical with using HP GL 2 on other color printers or plotters However these two color printers add a few HP GL 2 commands and expand the functionality of some existing commands This chapter describes these commands and other pertinent points to keep in mind when using HP GL 2 with these color printers The HP GL 2 commands explained in this chapter include the following The Merge Control MC command which functions in a similar way to the PCL logical operation command The Pen Color PC command which modifies palette colors the Number of Pens NP command which changes the palette size the Pixel Placement PP command which determines how pixels are rendered in HP GL 2 polygons and the Color Range CR command which sets the range for specifying relative color data
78. W Ve bOW e b0W Ve bOW e b0W e b0W e b0W e b0W e b0 Raster Graphics 6 43 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOWNe bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOWNe bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOWNe bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bOW e b0 W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOWNe bOW e bO W e b0W Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW Ve bOW e bOW e bO W e b0W Ve bOW
79. White EN Using Palettes Color LaserJet 5 5M DeskJet C 13 Bits Index 3 through 8 Index Color Black Red Green Yellow Blue Magenta Cyan White Black C 14 Using Palettes Color LaserJet 5 5M DeskJet EN Device CMY and Device Independent Palettes A CID command specifying either a device independent color space or the Device CMY color space creates the same default palettes This is because device independent colors are transformed into the printer s native space Device CMY Bits Index 1 Index Color 0 White 1 Black Bits Index 2 Index Color 0 White 1 Cyan Magenta Black Bits Index 3 through 8 Index Color 0 White 1 Cyan 2 Magenta 3 Blue 4 Yellow 5 Green 6 Red 7 Black n gt 7 Black Using Palettes Color LaserJet 5 5M DeskJet C 15 HP GL 2 Palettes Regardless of the color space a default PCL palette is always different than a default HP GL 2 palette The following table shows the default palettes established in HP GL 2 Like a default CID palette a default HP GL 2 palette can be modified in either PCL or HP GL 2 contexts using the following commands PCL Color Components 1 2 and 3 Ec v A Ec v C Assign Color Index Ec v l HP GL 2 Number of Pens NP Pen Color Assignment PC Set Relative Colo
80. Y Offset command with a value field of 1 sets the seed row to zero and prints the zeroed row Note that the next delta row is applied to a zeroed seed row Other cursor position moves set the seed row to zeros Remember non graphic cursor moves have the same effect as an end graphics command If the byte count of the Transfer Raster Data command value field is less than the number of bytes that can be replaced the byte count has precedence Also if the last byte is a control byte it is ignored Therefore Ec b1W does not affect the seed row but causes the previous row to be replicated Example Delta Row Compression The following example demonstrates how to compress the following data using the delta row compression The bytes highlighted in bold type indicate those bytes needing replacement those bytes that are different from the previous row the seed row Byte No 0 1 2 3 4 Row 1 00000000 11111111 00000000 00000000 00000000 Row 2 00000000 11111111 11110000 00000000 00000000 Raster Graphics 6 27 Row 3 00001111 11111111 11110000 10101010 10101010 Ec r1A The start raster graphics command initializes the seed row to all zeros Row 1 Ec b3m2W 00000001 11111111 The 3m selects the delta row compression method and the 2W indicates 2 bytes of data to follow The first three bits of the first data byte the command byte signify a single byte replacement all three bits are 0 The next five bits indicate an off
81. a Transfer Raster command Ec b V Ec b W Raster mode is exited explicitly by an End Raster command Fc rC or implicitly by a non raster command Raster Color vs Non Raster Color Palettes are used differently depending on whether the printer is in raster mode n non raster mode the palette is always used for color selection The color of text or patterns is specified using the Foreground Color command Ec v S In raster mode the palette is only used for indexed color selection it is not used for direct color selection Indexed and direct color selection are explained later in this section EN Color Printing Overview Color LaserJet 5 5M DeskJet A 3 Device Dependent vs Device Independent Color Device dependent color spaces are relative to the device s ability to produce specific colors For example if red is specified in a device dependent color space two different printers will combine the same amounts of cyan magenta yellow and black toner to produce the color but the results will be different because of the different properties of the toner Device independent color is specified absolutely in a color coordinate system that is independent of any device For example if red is specified in a device independent color space two printers will always produce the same result even though they may need to combine different amounts of cyan magenta yellow and black toner Printers that produce device independent
82. a source raster height was specified Allows raster commands which were previously locked out to be processed Sets compression mode to 0 no compression Defaults the left graphics margin to X position 0 Note This command is a modified version of the Fc rB End Raster Graphics command The newer version Ec rC performs two additional operations it resets the compression mode to 0 and defaults the left graphics margin to 0 This command is not supported by the HP LaserJet III or the HP LaserJet printers Use the c rB End Raster Graphics command to terminate raster graphic data transfers for these printers Refer to the PCL Feature Support Matrix in Chapter 1 of the PCL 5 Comparison Guide for specific printers which support these commands EN Raster Graphics 6 35 Raster Scaling Note Raster scaling provides the ability to enlarge or reduce raster images using the Destination Raster Width and Destination Raster Height commands The Start Raster command Ec r A with a value field of 2 or 3 turns on scale mode Scaling is independent of device resolution To use raster scaling the Configure Image Data command Fc rstW must be sent prior to the Start Raster command Fc r amp A which must have a value field of 2 or 3 to enable scaling There are two types of raster scaling Resolution and Arbitrary The scaling type is selected by the argument to the Start Raster command If either 0 or 1 are used th
83. aces that are linear transformations from CIE XYZ tristimulus coordinates gamma and gain are set to 1 0 otherwise they are set appropriately Colorimetric RGB spaces can be used for any monitor having primaries specified as CIE xy chromaticity coordinates with white point such as the Sony Trinitron or Hitachi Color Monitor Byte 15 msb 8 7 Isb 0 Byte 0 Color space Pixel encoding mode 1 2 Bits per Index Bits per primary 1 3 4 Bits per primary 2 Bits per primary 3 5 6 x Chromaticity for red primary msw 7 8 x Chromaticity for red primary Isw 9 10 y Chromaticity for red primary msw 11 12 y Chromaticity for red primary Isw 13 14 x Chromaticity for green primary msw 15 16 x Chromaticity for green primary Isw 17 18 y Chromaticity for green primary msw 19 20 y Chromaticity for green primary Isw 21 B 20 Using Color Modes Color LaserJet 5 5M DeskJet EN EN Byte 15 msb 8 7 Isb 0 Byte 22 x Chromaticity for blue primary msw 23 24 x Chromaticity for blue primary Isw 25 26 y Chromaticity for blue primary msw 27 28 y Chromaticity for blue primary Isw 29 30 x Chromaticity for white point msw 31 32 x Chromaticity for white point Isw 33 34 y Chromaticity for white point msw 35 36 y Chromaticity for white point Isw 37 38 Gamma for red primary msw 39 40 Gamma for red
84. amut CIE Lab Match n Screen Match EN Modifying Output Color Color LaserJet 5 5M DeskJet D 21 function Description Argument Range index 5 Download Color 1 CMY Color Space Map 3 CIE Lab Color Space See List 14739 bytes For the original Color LaserJet printer the color treatment arguments were slightly different 0 Process Blue 1 Vivid and 2 Business Blue The following paragraphs describe the function_index values and their arguments Lightness Negative values darken unlighten the image text or graphics color but do not have any effect on black or white data Positive values lighten the image Zero turns the lightness adjustment off This function index requires three data bytes Saturation Negative values desaturate add gray to the image text or graphics color but will not have any effect on black or white data Positive values increase the amount of saturation making the image more vivid Zero turns the saturation adjustment off This function index requires three data bytes Scaling Pixel replication is a backward compatible scaling algorithm Bilinear interpolation is a high quality scaling algorithm for smooth edge interpolated scaling Modified bilinear scaling only interpolates when it is best to do so This function index requires three data bytes Select Treatment This value specifies which col
85. and change a color image to monochrome Color lookup tables can remap colors to compensate for various differences in input data such as unwanted color casts caused by unbalanced photographic light sources Gamma correction provides a way to adjust for color differences in display monitors so that the display more closely matches the printed output Since the appearance of colors changes under different viewing light sources the Viewing llluminant command allows the application to modify output color based on the light source used to view the printed page A 2 Color Printing Overview Color LaserJet 5 5M DeskJet EN Color Concepts This section describes some of the concepts and terminology used in this chapter such as palettes raster vs non raster color device independent vs device dependent color black and white references color selection pixel encoding and color modes Palettes A palette is a collection of colors that are selected by their index numbers You can create your own palette or choose from one of several fixed palettes Although only one palette is active at any time all palettes are assigned ID numbers and can be stored in the printer for later selection using the ID number They can be deleted when desired Palettes can also be saved pushed to a stack and later retrieved popped when needed Raster Mode Raster mode is entered explicitly by the Start Raster command Ec r A or implicitly by
86. and specifies the first component of the palette entry designated by the Assign Color Index command Ec v l Ec v A First Component Default 0 Range 32767 0000 to 32767 0000 up to 4 decimal places command is ignored for invalid configurations The Assign Color Index command actually applies this value and then resets it to 0 Color Component Two This command specifies the second component of the palette entry designated by the Assign Color Index command Ec v B Second Component Default 0 Range 32767 0000 to 32767 0000 up to 4 decimal places command is ignored for invalid configurations The Assign Color Index command actually applies this value and then resets it to 0 Using Palettes 3 19 Color Component Three This command specifies the third component of the palette entry designated by the Assign Color Index command Ec v C Third Component Default 0 Range 32767 0000 to 32767 0000 up to 4 decimal places command is ignored for invalid configurations The Assign Color Index command actually applies this value and then resets it to 0 Assign Color Index This command assigns the three current color components to the specified palette index number Ec v l Index Number Default 0 Range 0 to 2 1 where is the number of bits per index no assignment for out of range values This command resets the color components to 0 after assignment If the specifi
87. and the pixel encoding mode reverts to indexed planar A value field of 1 creates a 2 entry Black and White default palette A value field of 3 creates an 8 entry Device RGB palette compatible with a PCL Imaging Mode palette but not an HP GL 2 default IN palette A value field of 3 creates an 8 entry palette in Device CMY color space B 4 Using Color Modes Color LaserJet 5 5M DeskJet EN EN The Simple Color palettes are shown below Single Plane value 1 Index Color 0 White 1 Black 3 Plane RGB value 3 Index Color 0 Black 1 Red 2 Green 3 Yellow 4 Blue 5 Magenta 6 Cyan 7 White 3 Plane CMY value 3 Index Color 0 White 1 Cyan 2 Magenta 3 Blue 4 Yellow 5 Green 6 Red 7 Black Using Color Modes Color LaserJet 5 5M DeskJet B 5 PCL Imaging Mode The PCL Imaging mode entered using the Configure Image Data CID command Ec v W creates a variable sized programmable palette It provides halftoning in the printer with multiple color spaces pixel encoding modes and reprogrammable palettes Configure Image Data CID Command The CID command provides configuration information for creating palettes and transmitting raster data The CID command performs the following Designates the color space for the default palette Designates the size of the palette to be created Provi
88. ange for device dependent color spaces However device independent color spaces require input data pre scaled to the range 0 to 255 For example to use the short form for the default YUV color space the input data must have the following ranges Y 2 0 0 to 1 0 0 89 to 0 89 0 70 to 0 70 The user must linearly scale y 2 mx b the input data to the range 0 255 Y 0 0 0 to 255 1 0 U 0 0 89 to 255 0 89 V 0 0 70 to 255 0 70 B 16 Using Color Modes Color LaserJet 5 5M DeskJet EN Note EN Long Form of CID Command Configure Image Data In addition to the short form there is also a long form of the CID command for each color space In device independent color spaces the long form can specify primaries other than the defaults provided by the short form For example a Sony Trinitron RGB primary base can be selected for Colorimetric RGB instead of the default non linear SMPTE RGB primaries Device RGB Long Form The long form for the Device RGB color space value field 18 provides explicit entry of black and white references range is 32767 to 32767 Black and white references are used in the direct pixel encoding modes 2 3 to set relative limits for raster data they are also used when specifying the primary components of new palette entries Ec v A Ec vitB Ec v C Black and white references have no effect on CID default palette colors The reference values are specified as 16 bit
89. aphics resets the Raster Compression Method 3 seed row but does not reset the Raster Compression Method nor the left raster graphics margin If source and or transparency modes have been set frequent start end graphics commands in an image can result in a memory overflow condition 6 18 Raster Graphics EN Raster Y Offset Command Note EN The Raster Y Offset command moves the cursor position vertically the specified number of raster lines from the current raster position in the raster area Ec bist Y Number of raster lines of vertical movement Default N A Range 0 32767 This command is recognized only while in raster graphics mode and only within the raster area This command zero fills the offset area For color printers zero fills are filled with the color of index 0 which is not necessarily white For Delta Row compression method 3 this command zeros the seed row For Adaptive compression method 5 this command applies to the entire raster data block Movement by this command is based upon the Raster Resolution setting Fc t R and also the printer s resolution setting 75 150 or 300 dpi Raster Graphics 6 19 Set Compression Method Command The Set Compression Method command allows you to encode the data in a given raster transfer either by plane or by row These methods achieve data compression by exploiting byte to byte redundancies either within a row or between rows without regard t
90. as either device dependent or device independent Both categories encompass many color spaces each with unique characteristics Device Dependent Color Device dependent color is relative to the device s inherent characteristics For example the colors produced by plotters are relative to the color of the installed plotter pens Pen color varies considerably especially as pens wear out changing the color of the output Likewise for monitor screens the red green and blue screen phosphors determine the colors produced Fully saturated colors can vary greatly between screens For printers the color produced on a page depends on the printer s subtractive inks or toner cyan magenta yellow and black When using device dependent color devices receiving relative color specifications for the same color frequently do not produce the same color For example a monitors saturated red may be different than a plotter s In short the same color page may appear considerably different on different devices The HP color printers provide device dependent color specified using either the Device RGB or CMY color spaces Device Independent Color In contrast with device dependent color device independent color is based on an absolute color standard the tristimulus values of human vision The device whether a printer or otherwise is calibrated to match an independent color specification The color specification is translated in such a way tha
91. at current cursor position current X position 2 Raster scaling on start at left boundary 3 Raster scaling on start at CAP Default 0 Range 0 3 out of range values default to 0 A value of 0 specifies that the left graphics margin is at the default left margin of the page X position 0 A value of 1 specifies that the left graphics margin is at the current X position Values of 2 or 3 are equivalent to 0 and 1 but also enable resolution independent scaling In presentation mode 3 the location of the left graphics margin varies depending on the orientation Once a Start Raster Graphics command is received by the printer raster graphics resolution raster graphics presentation mode raster height raster width and left raster graphics margin are fixed until an end raster graphics command is received Once in Raster Graphics Mode PCL commands and text imply an End Raster Graphics Fc rC except for the following commands Transfer Raster Data by Row or by Plane Set Raster Compression Method Raster Y Offset In addition the following commands are ignored i e locked out while in Raster Graphics Mode and do not imply an End Raster Graphics command Start Raster Graphics Set Raster Width Set Raster Height Set Raster Presentation Mode Raster Graphics 6 17 Set Raster Graphics Resolution Palette Commands CID Command Color Treatment Render Algorithm Note An implied End Raster Gr
92. ates a fixed size fixed color unmodifiable palette Depending on the value field Fc r amp U can create a 2 pen Black and White palette an 8 pen RGB palette or an 8 pen CMY palette When using the Simple Color mode the pixel encoding mode is always indexed planar PCL Imaging Mode PCL Imaging Mode enabled by the Configure Image Data command Ec v W allows a maximum of 24 bits per pixel for color specification Therefore more colors produced by halftoning may be specified than are obtainable in Simple Color Mode In the PCL Imaging Mode pixel encoding mode bits per pixel bits per primary white black references and the color palette are all programmable B 2 Using Color Modes Color LaserJet 5 5M DeskJet EN EN HP GL 2 Imaging Mode In HP GL 2 the Initialize IN command starts color imaging and performs the following Sets the pixel encoding mode to index by plane Sets bits per index to 3 Creates an 8 pen palette that is reprogrammable in either PCL or HP GL 2 contexts see Appendix C Using Palettes for more information Although default HP GL 2 palettes are different than default PCL palettes an HP GL 2 palette is modifiable in either PCL or HP GL 2 using the Assign Color Index Fc vstl or Pen Color PC commands respectively Likewise a PCL palette created by the Configure Image Data command Fc vitW is modifiable in both PCL and HP GL 2 using the same commands The active palette is a
93. ation refer to page 5 12 for source pattern transparency interactions Table of Logical Operations The Logical Operations ROP3 table Table 5 4 shows the mapping between input values and their logical operations Note that the logical operations are specified as RPN reverse polish notation equations Here is a key to describe what the Boolean Function values mean S Source AND Texture OR D Destination n NOT x EXCLUSIVE OR Note Since logical operations are interpreted in RGB space white 1 and black 0 rather than in CMY space white 0 and black 1 the results may not be intuitive For example ORing a white object with a black object in RGB space yields a white object This is the same as ANDing the two objects in CMY space It must be remembered that the printer operates in something similar to a CMY space and inverts the bits and reverses the order 5 18 The PCL Print Model EN EN Table 5 4 Logical Operations ROP3 Boolean Boolean Input Value Function Input Value Function 0 0 27 SDTSxaxn 1 DTSoon 28 TSDTaox 2 DTSona 29 DSTDxaxn 3 TSon 30 TDSox 4 SDTona 31 TDSoan 5 DTon 32 DTSnaa 6 TDSxnon 33 SDTxon 7 TDSaon 34 DSna 8 SDTnaa 35 STDnaon 9 TDSxon 36 STxDSxa 10 DTna 37 TDSTanaxn 11 TSDnaon 38 SDTSaox 12 STna 39 SDTSxnox 13 TDSnaon 40 DTSxa 14 TDSonon 41 TSDTSaoxxn 15 Tn 42 DTSana 16 TDSona 43 SST
94. ber is identified by the Pattern ID command described earlier in this chapter Note For selecting or changing the current pattern the Select Current Pattern Ec v T and the Pattern ID Fc c G commands work together Sending the current pattern Select Current Pattern command alone does not change the current pattern the Pattern ID must be sent first However when selecting solid white white rule or solid black black rule only the Select Current Pattern command is required Once a current pattern is selected that pattern applies to all images placed on the page until a new pattern is selected 5 32 The PCL Print Model EN User Defined Pattern Graphics In addition to the eight shading patterns and six cross hatch patterns users can design their own fill patterns These user defined patterns are downloaded to the printer and controlled using three commands Download Pattern c c W data Set Pattern Reference Point Ec p R Pattern Control Ec p Q Using User Defined Patterns To create a new pattern a user defines a binary raster data image as a base pattern This base pattern is downloaded to the printer using the User Defined Pattern command Prior to downloading the pattern a Pattern ID command is sent to assign the user pattern an ID number This ID number is used to select the pattern for printing and for pattern management To apply the pattern to an image the printer duplicates or tiles like placing ceramic ti
95. c RGB in the Color LaserJet and Color LaserJet 5 printers The value 2 is used to represent SRGB since it is analogous to a standardized Colorimetric RGB and the intent of the two color spaces is the same 2 6 Using Color Modes EN Note EN Byte 1 Pixel Encoding Mode This byte designates the format of any subsequent raster images The range of the value is zero to three All other values for this field are ignored Value Pixel Encoding Restrictions Mode 0 Indexed by Plane Bits Index can only be 1 2 3 4 5 6 7 or 8 Bit Components 1 2 and 3 are ignored 1 Indexed by Pixel Bits Index can only be 1 2 4 or 8 Bit Components 1 2 and 3 are ignored 2 Direct by Plane Bits Components 1 2 and 3 must be 1 3 Direct by Pixel Bits Components 1 2 and 3 must be 8 The number of bits per index determines the size of the palette created by this command In the case of the Indexed by Plane mode the number of planes needed to represent the index is also determined by the number of bits per index Therefore if a 256 entry palette is needed then the bits per index is set to eight since 28 256 If the Indexed by Plane mode is chosen at most eight planes are needed to represent each row of data The recommended pixel encoding mode is Direct by Pixel since this gives the most efficient raster processing However using this mode means that delta row compression should be used since it exploits red
96. ce Transparency Mode 5 7 Pattern Transparency Mode 5 8 Logical Operations 1 exe EE Sa PER ee ed als 5 9 Logical Operations and Transparency 1 lt 5 12 Logical Operation 5 13 ROPs in the RGB Color 5 14 ROPs in the CMY Color 5 15 Using a iit Date ebat Ege eee eat tae es 5 16 Table of Logical Operations 5 18 Pixel Placement 5 IRR E ER A cq RUE EU eee 5 24 Pixel Placement 5 27 Filling with Patterns 2 ee xx bs eee oe RR RUE b RO ERES EEG UY 5 28 Pattern ID Area Fill ID 5 29 Select Current Pattern 5 32 User Defined Pattern 5 33 Using User Defined Patterns 5 33 How the Printer Tiles a 5 34 Pattern Reference 5 36 Download Pattern Command 5 38 User defined Pattern
97. cify the color format so that the image data can be interpreted correctly For vector graphics and text the PCL 5 color commands support the application of a color from a palette of colors Each color printed is synthesized from a combination of three colors Cyan Magenta and Yellow The way the three colors are combined to produce the desired color is called a half tone and the PCL 5 color command Render Algorithm specifies which half tone to use for a color Advances in Hewlett Packard printers have allowed HP to reduce the number of render algorithms to Best High and Low While the actual implementation of each of these algorithms may vary from printer to printer HP has determined that the three algorithms are sufficient to produce high quality color documents containing text and graphics The colors that appear on a page also have one of two color treatments applied to them 1 Screen Match SRGB which provides the best WYSIWYG color This is the default color treatment 2 The Vivid color treatment which provides access to the entire device gamut range of colors the printer can produce However these colors are less correlated to those shown on a monitor than colors that have had the Screen Match treatment applied The following factors form the heart of the PCL color graphics state The palette of colors to be used in a document The render algorithm to print the colors The color treatment to be applied to each colo
98. ction model is the default pixels are rendered on the intersections of the device dependent grid covering the page In the grid centered model the number of rows and columns are each reduced by one and pixels are placed in the center of the squares rather than at the intersections The following example illustrates the concepts of the two models see Figure 5 5 Assume a rectangle extends from coordinate position 1 1 to position 3 4 As shown below for the same coordinates the grid centered model produces a rectangle that is one dot row thinner and one dot row shorter than the grid intersection model Thus the grid centered model should be selected when two or more polygons on a page may share a common border Since PCL printers print only at the intersections of the grid the actual implementation of the grid centered model is shown on the right 5 24 The PCL Print Model EN Grid Intersection Centered Actual Grid Centered indows Implementation Figure 5 5 Pixel Placement Note The grid centered method is used by Microsoft Windows When rectangular area fills are used and grid intersection is used an overlapping of pixels can occur if rectangular area fills are placed adjacent to one another as shown below Depending on the raster operation presently in effect this overlap can produce undesirable results in the final printed image To avoid t
99. d rectangular areas is essentially the same except that for text and raster images the Current Pattern Ec v T command is used and for rectangular areas the Fill Rectangular Area Ec c P command is used The procedures below describe how to fill with PCL and HP GL 2 patterns Patterns for Text and Raster Images Use the following general procedure to fill text and raster images with a non solid pattern 1 Specify the Pattern ID command For HP defined patterns select an ID that specifies the desired pattern 2 Download the pattern Ec c W This step is for user defined patterns only The downloaded pattern adopts the current pattern ID 3 Apply the pattern to all subsequent text and raster images Specify the current pattern type Fc vstT Patterns for Rectangles Use the following general procedure to apply a non solid pattern to rectangular areas 1 Specify the Pattern ID Ec c amp G For HP defined patterns select an ID that matches an HP defined pattern 2 Download the pattern Fc c W This step is for user defined patterns only The downloaded pattern adopts the current pattern ID 3 Define the rectangle Position the cursor and specify the rectangle size or Ec c H Ec c V 4 Apply the pattern to the rectangle Send the Fill Rectangular Area command HP GL 2 Patterns PCL patterns can be used in HP GL 2 mode but HP GL 2 patterns cannot be used in PCL mode Us
100. d for device independent color Snap to Primaries This algorithm converts each component of a color specification to its corresponding primary color For example assuming 8 bits per primary an RGB input value greater than 128 snaps to 255 a value less than or equal to 128 snaps to 0 Snap Black to White Colors to Black Choosing this option converts black to white and all other colors to black Input primary colors equal to a black specification are converted to a white specification and other color specifications for the input primaries are converted to the black specification Device Best Dither This dither pattern produces the best results for many images Note however that the recommended dither pattern varies with the image the intended use of the image and the subjective judgements of the user Error Diffusion The input primaries of a given pixel x y are printed at the closest density available and the local error is propagated to the unprinted neighboring pixels Error diffusion applies only to raster data printed using the Configure Image Data command D 4 Modifying Output Color Color LaserJet 5 5M DeskJet EN Ordered Dither and Clustered Ordered Dither The ordered dither or cluster ordered dither causes a pixel to be intensified at a point x y depending on the desired intensity I x y and on an n x n dither matrix D where modulo j modulo For RGB color spaces if lt
101. d if a palette is to be copied to its own ID Using Palettes Color LaserJet 5 5M DeskJet C 9 The Palette Control command provides a way of managing system memory by deleting palettes in either the stack or store that are no longer in use Palette Control that is exercised during macros can have significant impact on palettes that exist within the system Deleting all palettes or those on the stack or the current palette or all those except on the stack can have adverse effects when the macro is exited The adverse effect could be the deletion of the desired palette and replacement with a black and white non programmable palette C 10 Using Palettes Color LaserJet 5 5M DeskJet EN Simple Color Palettes EN The Simple Color command Fc rstU provides a quick way to select colors from a fixed non programmable palette The Simple Color command overwrites the current palette with one of the fixed palettes below When the Simple Color command is in effect the PCL and HP GL 2 commands that modify a palette entry NP CR PC Ec vitA Ec v B Ec v C Ec v l Ec t l are locked out A popped simple color palette cannot be modified and the pixel encoding mode reverts to index by plane Only the IN or the CID Ec v W commands can create a modifiable palette As shown below a value field of 1 Fc r1U creates a black and white palette A value of 3 creates an 8 pen palette in Device RGB color space A value of 3 creates a
102. d render algorithm mode 1 Print using gray scale equivalent Default 0 Range 0 1 command is ignored for invalid values This command must be sent prior to printable data or it is ignored The command must be sent at the start of a job since few if any applications support a mixture of color and monochrome printing of color images within the same document Modifying Output Color 4 3 Driver Configuration Command This command specifies the color treatment applied to each color specification Ec ostW device id function index Arguments Specifies the number of bytes to follow device ID function index arguments Default N A Range see description below device id Value Printer 6 Color LaserJet printer family 8 Color LaserJet 4500 printer function index function Description Argument Range index 4 Select Color 3 Vivid Graphics Traaungnt 6 Screen Match The following paragraphs describe the function index values and their arguments Select Treatment This value specifies which color treatment mode to use for rendering the next job Vivid Graphics This setting adds color saturation to the resulting image and provides access to the full gamut of the printer at the cost of color matching 4 4 Modifying Output Color EN Note EN Screen Match Due to the emergence of sRGB standard Red Green Blue as an international color data standard there is no
103. define a palette of colors Each color is specified by three quantities or values which are interpreted depending on the color space For example the color white in an RGB palette is 1 1 1 while this set of values in a CMY palette defines the color black Each color in the palette is accessed using an index number starting with O as the first color in the palette The largest palette holds 256 colors which is approximately the largest set of distinct colors the human eye can distinguish under normal viewing conditions A color from a palette can be applied to either text or vector graphics using the Foreground Color command Once the command is invoked the selected color will be applied to all text and vector graphics page marking primitives and to a certain extent to raster images Palettes can be identified with a Palette ID and then stored and recalled as needed A palette stack mechanism is also supported for the convenience of applications that work well with a graphics stack PCL 5 Color Graphics Context The Palette acts as the focal point of the PCL 5 color graphics context The color space render algorithm color treatment and pixel encoding mode are stored along with the palette Therefore selecting or restoring a palette also restores these values PCL 5 Color Mode The PCL language has four modes or ways of specifying and using color Black and White monochrome mode is the default mode so that backward compatibil
104. des data for transforming color space specific values into device specific values Provides data for transforming device dependent data monitor RGB to device independent Colorimetric RGB Designates the format of raster data and how primary components are combined to yield the raster representation Ec vitW binary data Number of data bytes Default NA Range Short form 6 bytes Long form gt 6 bytes Invalid configurations of the CID command are ignored and the data discarded Any signs in the value field are ignored The data fields in this command must contain byte aligned binary data not ASCII data This command has two forms the six byte short form described below and the long form consisting of these six bytes plus additional information specific to the color space B 6 Using Color Modes Color LaserJet 5 5M DeskJet EN Common 6 Byte Header The short and long forms of the CID command use a common 6 byte header regardless of which color space is specified The header data fields whose meaning may vary according to the color spaces are present in all color space specifications The short form and long form of the CID command are explained separately in the following pages Byte 15 MSB 8 7 0 LSB Byte 0 Color space UBYTE Pixel encoding mode 1 UBYTE 2 Bits index Bits primary 1 3 UBYTE UBYTE 4 Bits primary 2 Bits primary 3 5 UBYTE UBYTE Byte 0 Colo
105. difying Output Color This chapter explains the options for modifying the output color the Render Algorithm command the Monochrome Print Mode command Driver Configuration command and Finish Mode command Chapter 5 The PCL Print Model Chapter 5 describes the print model and how it determines the printed outcome when various patterns colors and images are applied together on a page This chapter discusses the role that logical operations and transparency modes have on this process Chapter 6 Raster Graphics This chapter describes the raster graphics commands and also compressing raster graphics images using various compression methods Chapter 7 Color Vector Graphics HP GL 2 This chapter discusses printing color pages using HP GL 2 the vector graphics language included on all PCL 5 printers The chapter describes new and or modified HP GL 2 commands and how they are used to print with HP color printers Appendix A Color Printing Overview Color LaserJet 5 5M DeskJet Appendix A explains background information about printing color documents using PCL 5 Topics include palettes device dependent vs device independent color color selection pixel encoding color modes and color matching Appendix B Using Color Modes Color LaserJet 5 5M DeskJet Appendix B defines the color modes for the HP Color LaserJet Color LaserJet 5 5M and the DeskJet 1200C and 1600C printers and describes how to use them It include
106. ds the matrix data The printer selects the Continuous Tone Smooth 150 algorithm instead EN Color Lookup Tables EN Color lookup tables provide a way to re map color data for the following types of applications Highlight and shadow modification Saturation and desaturation Unique gamma correction curves Special effects for tonal correction Neutral balancing Color lookup tables map input data for each primary color into a new output range based on point by point conversions Color lookup tables can modify input data for both device dependent and device independent color spaces Like the CID command the first byte of the data field identifies the color space to which the lookup tables will be applied These tables specify on a point per point basis a transformation from an input space of 0 255 into an output space of 0 255 Figure 0 1 the next page illustrates the concept The unity lookup table see the following illustration is the default for all color spaces it performs a 1 1 mapping of input to output that is 129 is mapped to 129 The inversion lookup table performs a simple color inversion for example it inverts the red primary of a device dependent RGB color space to create cyan output from 255 red to 0 red which is 255 cyan Color Lookup Tables Command This command enables and specifies color lookup tables L W binary data Number of bytes of binary data Default
107. e Destination for all possible combinations of Texture Source and Destination The way the bits of the ROPs number map to the combinations of Texture Source and Destination depends on whether the color space is RGB or CMY The least significant bit of the RGB ROP value maps to 0 0 0 the color black in RGB and the most significant bit to 1 1 1 white in RGB On the other hand the CMY ROP reverses the mapping This reversal hinges on the fact that RGB and CMY are the inverse of each other i e RGB Black is 0 0 0 and CMY Black is 1 1 1 white All other colors show the same relationship ROPs in the RGB Color Space The RGB ROP truth tables shown in Table 5 1 illustrate how ROP 252 and ROP 90 work and most importantly how the bits in the ROP map show destination values for each combination of Texture Source and Destination A 1 in the RGB color space represents white and a 0 black which makes determining what shows on paper cumbersome for users since the paper is marked when the Destination has a 0 value 5 14 The PCL Print Model EN Table 5 1 RGB ROP Truth Tables ROP gp 252 ROP 90 ROP gp 11111100 01011010 nz bzbgbsb4bsbsb bo TS DID TS DID T S D ROPn D 1 wie ao 1 0 bz o 1 h b 1 1 bo H 1 h 0 bg 1 o d 1 i 0o o 1 0 bbs i o jo 4 1 o 0o H 1 b b 0 us 14 o ho
108. e 1 1 d d Wd d i1 Example In the example below the row transfer commands are shown in binary for clarity even though the actual data would be byte aligned binary data The example is for an eight pixel wide image Ec v6W 00 00 03 08 08 08 Binary data for CID represented in hex This command sets the color space to RGB the PEM to Indexed by Plane the palette size to 8 23 The last 3 bytes are ignored Ec r1A Start raster Ec b1V10110000 Transfer plane 1 the first bit for each pixel in the first row Ec b1V01110000 Transfer plane 2 the second bit for each pixel in the row Ec b1W10101000 Transfer plane 3 the third and final bit for each pixel in the row and move to the next row Note that the Ec b W command is used to send the last plane of each row 2 8 Using Color Modes EN PEM 1 INDEXED BY PIXEL In this mode each pixel in a row is fully specified before any bits are sent for the next pixel The bits for each pixel form a palette index number Assuming four bits per index the underlined block below is the palette index for pixel two of row one i1 is the least significant bit Ec b W row i4 i3 i2 i1 14 i3 i2 11 Ec b W row2 i4 i3 i2 11 i4 i3 i2 11 Ec b W 14 i3 i2 11 14 i3 i2 11 Example In the example below the data in the row transfer commands are shown as two digit hexadecimal numbers for clarity even though the actual data would be byte aligned binary data The example is for a
109. e palettes for different color spaces all without reconfiguring the active palette For example one palette can be created for PCL text one for HP GL 2 primitives one for simple raster and one for 24 bit raster The application can then switch between palettes according to what is being sent to the printer Selecting a new active palette changes the PCL graphics state Besides the color entries a palette also has the graphics state which contains the color space color treatment and render algorithm This ensures that the same color specification in a given palette will always produce the same printed color As described below the Select Palette Fc amp p S Palette Control Ec amp p C and Palette Control ID Fc amp p l commands implement the three basic operations of management by ID Selection of the active palette Deletion of palettes Copying of palettes Select Palette Command The Select Palette command selects a new active palette by specifying an ID number The previously active palette is unchanged Ec amp p S Palette ID number Default 0 Range 0 to 32767 command is ignored for out of range values This command activates the designated palette in the palette store The command is ignored if the specified ID matches the active palette s ID or if no palette with that ID exists The designated ID is saved as the palette select ID for the duration of the print job or until another Select Palette command
110. e the active palette with a non programmable black and white palette The HP GL 2 commands IN and DF have no effect on the palette stack but they do destroy the active palette and replace it with the default HP GL 2 palette 3 4 Using Palettes EN Palette Management by ID All palettes have a unique ID identification number The default black and white palette created on power up or FcE has an ID of 0 Palette management by ID lets applications have multiple palettes As shown below multiple palettes can exist in two areas the palette stack and the palette store The stack holds palettes that are pushed via a Push Pop Palette command the store holds palettes having palette IDs EN Palette Store Palette Stack Active Palette Top of Stack Pushed Palettes to Stack D Popped Palettes from Stack lt Note Palettes are pushed and popped from the top of the stack ID numbers are empty when on the stack Palettes on the stack may not be selected by ID since only a copy of a palette is pushed onto the stack the original palette and ID remain in the palette store A palette popped from the stack goes into the palette store becomes the new active palette and assumes the ID of the previously active palette which is overwritten Only one palette at a time may be active Using Palettes 3 5 Management by ID allows applications to tag data have multiple raster configurations and hav
111. e transparent source transparency 0 pattern transparency 0 The destination shows through these areas Transparency modes are set by the Source Transparency Fc vitN and Pattern Transparency Ec vstO commands The Print Model allows logical operations such as AND OR XOR NOT to be performed on source texture and destination images Transparency modes and Logical Operation must be specified before printable data is sent The PCL Print Model 5 9 Operators Source Transparency specified before logical operation default is transparent Pattern Transparency specified before logical operation default is transparent Logical Operators default is Texture OR Source Operands Source objects character cell raster image rule HP GL 2 vectors and polygons Texture foreground color pattern mask color pattern format 1 Destination current page definition Operation IF source transparent amp amp source white RETURN destination IF pattern transparent amp amp pattern white amp amp source white RETURN destination ELSE RETURN logical op source texture destination 5 10 The PCL Print Model EN Assuming three bits per pixel the following diagram shows the process AND OR Logical Either Foreground Pattern User Defined Color Mask Color Pattern N m Go Source Texture Destination lc d Logical Operation New Destination Fig
112. ecify Raster Presentation Mode 0 Ec r0F Print raster graphics in the orientation of the logical page 3 Specify the raster graphics resolution Ec t75R Set raster resolution to 75 dpi 4 Specify the raster graphics height Ec r32T Specify a raster height of 32 pixels 32 rows of raster data 5 Specify the raster graphics width Ec r32S Specify a 32 pixel raster width 6 Specify the left raster graphics margin Ec r1A Set the left graphics margin to the current X position 300 7 Specify the Y offset Ec bOY This specifies a Y offset of 0 this command is not necessary here but shows the proper command sequence 6 38 Raster Graphics EN 8 Specify the raster compression mode Ec bOM No compression unencoded 9 Transfer the raster data to the printer Divide the image into dot rows and transfer each dot row to the printer as a string of bytes as illustrated on the following page 10 Signify the end of the raster image transfer Ec rC This example prints the arrow as shown in Figure 6 7 Example of Raster Graphic Image Data Raster Image Data Command Data Dot Row byte 1 byte 2 byte 3 byte 4 Decimal Equivalent 1 00000000 00000000 10000000 00000000 EFc b4W 0 0 128 0 2 00000000 00000000 11000000 00000000 Fc b4W 0 0 192 0 3 00000000 00000000 11100000 00000000 EFc b4W 0 0 224 0 4 00000000 00000000
113. ed index number is greater than the palette size no index assignment is made but the three color components are set to 0 3 20 Using Palettes EN A Modifying Output Color Introduction The previous chapters of this manual have been concerned with giving an overview of the color printing process choosing color modes and using palettes This portion of the manual explains how color can be modified to produce a desired result from using halftone render algorithms to change the way color is rendered to selecting a color treatment and finish mode The HP color printers can modify colors using the following means Halftone render algorithms provide a way to modify images based on a dither cell concept The algorithm chosen determines how specified colors are rendered as dots on the printed page The Monochrome Print Mode command converts each color to its grayscale equivalent for faster draft printing The Driver Configuration command provides a way to select a color treatment The Finish Mode command allows the user to specify the finish matte or glossy to be applied to the document All of these methods of modifying output color are explained in the following sections EN Modifying Output Color 4 1 Halftone Render Algorithms The HP color printers have the capability of applying different halftone render algorithms to achieve the desired output on the printed image Render algorithms allow you to change the charact
114. eferences respectively for red the second pair sets the green references and the final pair the blue reference values If the black reference value for any primary is equal to the white reference value for the same primary the command is ignored The default for red green and blue black references is 0 the default for red green and blue white references is 255 This command is defaulted by the CR and IN commands Execution of this command causes current pen colors to be remapped to the new range so that current palette colors remain unchanged Color Vector Graphics HP GL 2 7 19 PP Pixel Placement When printing the printer places pixels at the intersection of the squares of a theoretical device dependent grid covering the printable area on a page When the sides of two HP GL 2 polygons touch each other the pixels along the border may be printed twice or not at all depending on the logical operation in effect For example if a source rectangle consisting of all 1 s is XORed with a destination consisting of all 1 s a white rectangle is printed If another source rectangle is placed on the page touching the first rectangle the two rectangles are white filled except at their common border that is 1 1 1 1 To correct this situation two models of pixel placement are used grid intersection and grid centered The grid intersection model is the default pixels are rendered on the intersections of the de
115. efined by the corresponding bits in each plane Ec b1V01110000 Transfer plane for primary color 2 Each bit turns on or off the green primary of the pixel Ec b1W10101000 Transfer plane for primary color 3 and move to the next row Each bit turns on or off the blue primary of the pixel MODE 3 DIRECT BY PIXEL In mode 3 the color raster data is downloaded pixel by pixel as in mode 1 but each pixel directly specifies each color component as in mode 2 Assuming Device RGB space with 8 bits per primary the underlined block below defines the actual color primaries for pixel 1 of row 2 Ec b W 1 7 0 07 00 07 60 Ec b HW 2 r7 r0 97 50 b7 bO Ec b W 7 0 07 00 07 60 B 12 Using Color Modes Color LaserJet 5 5M DeskJet EN EN Example Ec v6W 00 03 00 08 08 08 Binary data for CID represented in hex Sets color space to RGB pixel encoding mode to 3 Palette size is ignored Send 8 bits to address each primary value for a pixel Ec riA Start raster Ec b3W 45 06 30 Each byte sets a primary value for the first pixel and moves to the next row 45 specifies the red 06 the green and 30 the blue component value of that pixel Byte 2 Number of Bits per Index In all pixel encoding modes this byte sets the size of the palette to 2 where n is the number of bits per index n pixel encoding modes 0 and 1 indexed where raster data is interpreted as ind
116. els uint 16 5 6 byte 0 ubyte byte 1 ubyte 7 8 byte 2 ubyte byte 3 ubyte 9 n Dither matrix height in pixels uint 16 1 2 Dither matrix width in pixels uint 16 n 3 n 4 byte 0 ubyte byte 1 ubyte n 5 n 6 byte 2 ubyte byte 3 ubyte n 7 m Dither matrix height in pixels uint 16 1 2 Dither matrix width in pixels uint 16 m 3 m 4 byte 0 ubyte byte 1 ubyte m 5 m 6 byte 2 ubyte byte 3 ubyte m 7 Example This example produces a 4 x 4 dither matrix that is applied to all three color primaries the number of planes is set to 1 The following command would be sent to create this dither matrix Ec m22W010404B0B1B2B3B4 B15 where the first 6 binary bytes are shown as ASCII here for clarity and B1 B15 indicate the binary byte data Modifying Output Color Color LaserJet 5 5M DeskJet D 11 Note Note D 12 Modifying Output Color Color LaserJet 5 5M DeskJet The byte aligned binary data field shown as ASCII for clarity would be Byte 15 msb 7 Isb 0 Byte 0 0 1 1 2 0 3 4 0 5 6 BO B1 7 8 B2 B3 9 20 B14 B15 21 Do not use downloaded dither matrices as patterns since the orientation of the pattern will not rotate with changes in orientation and page rotation HP Color LaserJet 5 and 5M printers do not support the Download Dither Matrix command When this command is sent the printer parses and discar
117. ement bytes replace bytes 7 8 9 10 and 11 the five bytes beginning at byte 7 from the seed row If there is more than one replacement in a row the second offset is counted from the next untreated byte in the row the first byte following the last replacement byte Indicates 2 Bytes Command Byte Il eee d 111111 Selects Delta Row Compression Mode Number of Data Replacement Bytes That Follow Byte Number of Bytes to Replace gt Relative Offset Raster Graphics 6 25 As mentioned the offset contained in the lower five bits of the command byte allows for offset values from 0 to 31 Compression mode allows offsets larger than 31 bytes as follows An offset value of 0 30 indicates that the replacement bytes are offset from the 1st byte to the 31st byte A value of 31 indicates that the next byte following the command byte is an additional offset byte which adds to the first 32 offset value This allows offset values larger than 31 Also if this second offset byte is set to 255 all ones additional offset bytes follow until the required offset value is obtained When the formatter detects an offset byte less than 255 it is assumed to be the last offset value and the offset bytes are then totaled added The following example shows an offset larger than 31 Replace 1 Byte Replacement Byte MEET lcd rra ve b3m4W888111111111111
118. en resolution scaling is performed If either 2 or 3 is used then arbitrary scaling is performed Resolution Scaling This scaling is performed using the raster resolution in combination with the device resolution For example if the raster resolution is set to 300 dpi and the device resolution is 600 dpi then the image is scaled by a factor of two This type of scaling does not depend on the source or destination raster dimensions Arbitrary Scaling This scaling is performed without regard to the raster resolution which is unaffected by scale calculations The scaling factor is determined by the source and destination raster dimensions If the destination dimensions are not specified the graphics margin and printable area are used to calculated destination dimensions while maintaining isotropic scaling so that the entire image fits on the page If only one destination boundary is specified the other is calculated to maintain isotropic scaling The destination width and height commands accept real numbers with up to four decimal places of precision This level of precision is necessary when converting from decipoints to pixels so that round off errors will not create visible print artifacts such as lines within the image 6 36 Raster Graphics EN EN Destination Raster Width The Destination Raster Width command defines the width in decipoints of the destination raster picture denoted by the next Start Raster command which must have
119. en using the Download Dither Matrix command you have several options You can choose whether to define a separate matrix for each color plane or use the same matrix for all three color planes You set the height and width of the dither cell When using separate matrices for each plane you can use different size dither cells for each plane For example you can have a 4 x 4 pixel cell for red a 4 x 6 cell for green and a 6 x 8 cell for blue You download the data bytes for each pixel of the cell Each data byte determines a threshold every pixel with a value greater than or equal to the threshold gets turned on and every pixel with a value less than the threshold does not get turned on HP Color LaserJet 5 and 5M printers do not support user defined dithers When a Download Dither Matrix command is sent the printer parses and discards the matrix data and selects the continuous tone smooth 150 Ipi algorithm instead Download Dither Matrix Command The Download Dither Matrix command specifies a single matrix for all three primary colors or three matrices one for each primary which may have different sizes and contents Ec mitW data Number of bytes of byte aligned binary data in the data field Default 0 Range 7 to 32767 command is ignored for values of 0 6 values larger than 32767 or device limits are clamped signs are ignored Modifying Output Color Color LaserJet 5 5M DeskJet D 7 A downloaded
120. eristics of the image by changing the way pixels are rendered Each halftone render algorithm produces a different affect on the output varying the texture and color appearance of the printed image To choose the type of rendering to be used use the Render Algorithm command described below Render Algorithm Command The Render Algorithm command selects the algorithm to be used for rendering page marking entities on a given page Ec t J 0 Continuous tone detail high Ipi device best dither 3 Device best dither 15 Continuous tone smooth high 1 1 18 Continuous tone basic low Ipi Default Range 3 0 3 15 18 invalid values are ignored Device Best Dither This dither pattern produces the best results for many images Note however that the recommended dither pattern varies with the image the intended use of the image and the subjective judgements of the user 4 2 Modifying Output Color EN Monochrome Printing EN The Monochrome Print Mode command converts each color value to its grayscale equivalent This improves throughput costs less to print and eliminates waste by providing a draft mode Monochrome Print Mode Command The Monochrome Print Mode command designates whether to print using the current rendering mode or a fast gray scale equivalent Pages printed using the gray scale equivalent do not use any color and therefore print faster and more economically Ec amp b M 0 Printin mixe
121. ern 5 48 The PCL Print Model EN Note EN The current pattern is not applied to a rectangular area unless specified by this command The order in which data patterns rules text raster is received is the order in which it is processed during the rasterization of the page The fill or pattern used as the current pattern is selected using the Select Current Pattern Ec vitT command Black fill value field 0 also known as black rule and the white fill value field of 1 patterns do not have a choice of different patterns and thus do not require a pattern specification using the Pattern ID command The upper left corner of the rectangular area is located at the cursor position when printing a rectangular area After printing the rectangular area the cursor is returned to the upper left corner the cursor position does not change positions as a result of printing a rectangular area Rectangular areas are independent of the text area and perforation skip mode these boundaries are ignored rectangles are not clipped at these boundaries Addressable rectangular areas are limited to the logical page Rectangular areas that extend outside the logical page are clipped at the logical page boundaries refer to the PCL 5 Printer Language Technical Reference Manual for logical page and printable area boundary specifications The pattern transparency mode controls how the area fill pattern is applied to the page Refer to the follow
122. es coiere ERE RAO EER OEM ee UR EON Reds A 3 Raster MOGOO enr ve hi deeded Sea oe EET Sah hee eda is A 3 Raster Color vs Non Raster A 3 Device Dependent vs Device Independent A 4 Black and White A 4 Color A 5 Pixel Encoding 32 y Ty bed Xa e ed OX CR deed A 6 Encoding by Plane zx 6 Color MOd6S 5 ecc eer ene Rx Rex ees ne A 7 Device Dependent Color A 8 Device Independent Color A 8 Device Independent A 10 Device Dependent A 10 Device Independent A 10 Color Matching s vee Ada Reda he ed eed eds A 11 Processing Color A 14 Non Raster Color vs Raster A 14 Color Raster A 14 Appendix B Using Color Modes Color LaserJet 5 5M DeskJet IMMOQUCHIOMN mE B 2 Simple Color
123. estination White pixels are unaffected by pattern or foreground color they are either white or transparent For RGB color images white pixels are those for which all color primaries are 255 For CMY color images white pixels are those for which all color primaries are O White dots introduced in the dithering process are not subject to transparency modes Refer to the preceding definitions and the discussion of Figure 5 3 for an explanation of the effects of source transparency The PCL Print Model 5 7 Pattern Transparency Mode Command The Pattern Transparency Mode command sets the pattern s transparency mode to transparent or opaque Ec v 0O 0 Transparent 1 Opaque Default 0 Range 0 1 other values cause the command to be ignored A transparency mode of 0 transparent means that the white regions of the pattern image are not copied onto the destination A transparency mode of 1 opaque means that the white pixels in the pattern are applied directly onto the destination Note When printing white rules the pattern transparency is treated as if it were opaque white rules erase black rules regardless of the transparency mode For RGB color images white pixels are those for which all color primaries are 255 For CMY color images white pixels are those for which all color primaries are 0 White dots introduced in the dithering process are not subject to transparency modes
124. f the source image s white pixels as they are applied to the destination image see the note below Setting the source transparency mode to 1 opaque applies the source image s white pixels to the destination image with a setting of 0 transparent these pixels have no effect on the destination 5 2 The PCL Print Model EN Pattern Transparency Mode The transparency or opaqueness of the white pixels in the pattern see the note below When set to 0 transparent these pixels have no effect on the destination when set to 1 opaque they are applied through the black pixels of the source pattern to the destination Logical Operations the Print Model uses logical operations such as AND OR XOR and NOT when determining which bits of the source pattern and texture become part of the resulting image The Logical Operations command Fc li O can vary the logical operation used thus varying the outcome Note For RGB color images white pixels are those for which all color primaries are 255 For CMY color images white pixels are those for which all color primaries are 0 For all rendering algorithms white dots introduced in the dithering process are not subject to transparency modes Figure 5 2 illustrates the effects of the source and pattern transparency modes on the final image The transparency modes Work a little differently with rectangular area fill see Pattern Transparency for Rectangular Area Fill near
125. fer PMO PM2 e Updates the current pen position to the lower left corner of the picture frame P1 Setting an HP GL 2 plot size e Changes the picture frame scaling factor Redefining the palette e Changes colors selected by the Select Pen SP command and used in patterns defined by the Raster Fill Definition RF command and or used by the Fill Type FT command Color Vector Graphics HP GL 2 7 5 MC Merge Control Note The MC command controls the color of pixels where two or more page marking primitives intersect on the page This command supports all 256 Microsoft Windows ternary ROP3 raster operation codes A common application of the MC command is the rendering of complex polygon fill patterns Raster Operations specify how source destination and patterns are combined to produce final images MC mode opcodej Parameter Format Functional Parameter Range Default mode clamped integer 0 or 1 O off opcode clamped integer 0 to 255 252 mode 0 168 mode 1 Mode defines the merge control mode as follows 0 off default Pixels in a primitive replace corresponding destination pixels If no opcode is specified 252 is used 1 on Pixels in a primitive merge with corresponding destination pixels creating a new color based on the colors of the source data and the contents of the destination frame buffer If no opcode is specified 168 is used This command is the HP GL 2 ve
126. fficient memory cause an out of memory error Attempts to pop from an empty stack are ignored Macros can push and pop palettes A palette that was popped in an executed macro remains in effect at the end of the macro this is not true for called or overlaid macros PCL reset commands cE and exits to PUL cause the printer to empty the palette stack and overwrite the active palette with a non programmable black and white palette The HP GL 2 commands IN and DF have no effect on the palette stack but they do destroy the active palette and replace it with the default HP GL 2 palette C 4 Using Palettes Color LaserJet 5 5M DeskJet EN Palette Management by ID All palettes have a unique ID identification number The default black and white palette created on power up or FcE has an ID of 0 Palette management by ID lets applications have multiple palettes As shown below multiple palettes can exist in two areas the palette stack and the palette store The stack holds palettes that are pushed via a Push Pop Palette command the store holds palettes having palette IDs EN Active Palette Top of Stack Pushed Palettes to Stack D r M Popped Palettes from Stack lt Palette Store Palette Stack Note Palettes are pushed and popped from the top of the stack ID numbers are empty when on the stack Palettes on the stack may not be selected by ID since onl
127. fies whether the pattern byte s represent a byte that is to be repeated some number of times up to 127 or represent some number of bytes up to 127 which are to be printed as is literally Raster Graphics 6 21 The sign of the number in the control byte identifies whether the byte or bytes that follow represent a literal pattern or byte to be repeated A positive number 1 to 127 indicates that the bytes are literal A negative number 1 to 127 represented by the twos complement indicates a repeated byte The value of the number if positive literal identifies the number of pattern bytes which follow the control byte if negative repeated it identifies the number of times to repeat the following byte A pattern byte may be repeated up to 127 times or up to 127 literal bytes may follow the control byte As mentioned for a byte to be repeated the control byte must be a negative value as represented by the twos complement For example to repeat a pattern three times would require the twos complement of the number 3 The twos complement is computed as follows The binary of 3 is 00000011 Complement each bit to get 11111100 then add one to this value to produce 11111101 the twos complement The decimal value of this number 253 used in the control byte produces a repetition of 3 bytes for a total of 4 occurrences of the pattern The range of numbers for the control byte is shown below Literal Pattern Values of Bytes
128. g from PCL to HP GL 2 active palette information does stay the same You can switch between PCL and HP GL 2 and use the same palette and you can also modify palettes using either PCL or HP GL 2 Compared to monochrome printers the Color LaserJet and DeskJet 1200C color printers have some commands that are modified for use with color printers Chapter 7 describes the new or modified HP GL 2 commands If you are not familiar with using HP GL 2 see the PCL 5 Printer Language Technical Reference Manual It provides a detailed explanation of using HP GL 2 B 28 Using Color Modes Color LaserJet 5 5M DeskJet EN Using Palettes Color LaserJet 5 5M eskJet Introduction A palette is a collection of color specifications selected using index numbers The figure below illustrates a palette Each palette entry associates an index number with three primary color components For HP GL 2 purposes only a pen width is also associated with each palette entry Color Table HP GL 2 Primary 1 Primary 2 Primary Pen Width 0 1 2 3 4 5 6 7 8 9 max 255 e Pixel Encoding Mode Bits per Primary e Pixel Color Selection e Primary 1 By Index or Direct e Primary 2 e Pixel Color Transfer e Primary 3 By Row or By Plane EN Using Palettes Color LaserJet 5 5M DeskJet C 1 In non raster mode the current palette contains all the colors available to the
129. ging mode HP GL 2 Imaging mode All four modes create a palette The palettes used in the Black and White mode and Simple Color mode are not modifiable You can however modify the palettes in the PCL Imaging and HP GL 2 Imaging modes You can use more than one mode on the same page For example you could enter the Simple Color mode to print a headline and a bar chart PCL Imaging mode to print a raster photograph and Black and White mode to print some body text Each mode is described in more detail in Appendix B Using Color Modes Color Printing Overview Color LaserJet 5 5M DeskJet A 7 Device Dependent Color Spaces The following PCL commands can alter color processing for device dependent color spaces Rendering Algorithm Ec t J Gamma Correction Fc til Color Lookup Tables Ec HtW Configure Image Data Ec v W Simple Color Fc ritU Monochrome Print Mode amp 0 Color lookup tables or gamma correction which are mutually exclusive can modify the mapping of input to output Device Independent Color Spaces The following PCL commands can alter color processing for device independent color spaces Rendering Algorithm Ec t J Gamma Correction Ec t l Color Lookup Tables Ec l W Configure Image Data Ec v W Viewing Illuminant Ec i W Monochrome Print Mode amp 0 Device independent color spaces are supported under the following conditions 1 The Configure Image Data command Fc vi
130. his command is used for both the Select Pattern and Rectangular Area Fill graphics For user defined patterns this command sent prior to downloading a user defined pattern assigns an ID pattern number to the downloaded pattern For more information see User Defined Pattern Graphics later in this chapter The PCL Print Model 5 29 1 2 11 2096 36 55 81 99 Figure 5 7 Shading Patterns 5 30 The PCL Print Model EN m m m Be D v v v E e 7 m D e we v m e p E ue Es m uu 2 Le jn ie pm Z KXXXXXX 79994409999 Oo 7 ff 4 SM 55 w Y 1 3 SS 4 3 15 de rint P L C P he T S tte a ch P t a H S S ro C 8 ure 5 ig Fi EN Select Current Pattern Command The Select Current Pattern command identifies the type of pattern to be applied onto the destination Ec vit T 4 0 Solid black or foreground color 1 Solid white 2 Shading pattern 3 Cross hatch pattern 4 User defined pattern Default 0 Range 0 4 values outside of range are ignored This command selects which type of pattern is applied For values 2 3 and 4 the desired shading level cross hatch pattern or user defined pattern num
131. his command pushes or pops the palette from the palette stack Ec p P 0 Push save palette 1 Pop restore palette Default 0 Range 0 1 invalid values are ignored A value of 0 Ec pOP pushes a copy of the active palette onto the palette stack When a palette is pushed the active palette is not affected A value of 1 Ec p1P pops the most recently pushed palette and destroys the active palette the popped palette becomes the active palette As with any stack the last item pushed is the first item popped Pushing a palette saves the following parameters Color definitions for each palette entry Pen widths for HP GL 2 use Color space specification Number of bits per index Pixel encoding mode Number of bits per primary Color treatment Render algorithm Using Palettes 3 3 Pushing a palette does not save the following parameters Foreground color Color components 1st 2nd and 3rd Finish mode Monochrome print mode The palette stack depth is limited by printer memory Attempts to push a palette with insufficient memory cause an out of memory error Attempts to pop from an empty stack are ignored Macros can push and pop palettes A palette that was popped in an executed macro remains in effect at the end of the macro this is not true for called or overlaid macros The PCL reset command or an exit to PUL causes the printer to empty the palette stack and overwrit
132. his problem use the grid centered method EN The PCL Print Model 5 25 Note Since PCL printers print only at intersections grid centered pixel placement is implemented as shown on the right Grid Intersection Grid Centered Common boundary overlap Common Boundary Printer XOR s these to produce No overlap undesired results X Pixels in first polygon area Q Pixels in second polygon area Figure 5 6 Pixel Placement Variations There are two commands that modify the pixel placement function the PCL Pixel Placement command Ec the HP GL 2 Pixel Placement command PP 5 26 The PCL Print Model EN Pixel Placement Command Note EN Determines how pixels are rendered in images Ec L R 0 Gridintersection 1 Grid centered Default 0 Range 0 1 command is ignored for other values Two models are used for rendering pixels when an image is placed on paper Grid Intersection Model Grid Centered Model This command can be used multiple times per page It has no effect except to switch the model being used for imaging The PCL Pixel Placement command determines how pixels are placed for both PCL and HP GL 2 operation This command performs the same function as the HP GL 2 PP command described in Chapter 7 The PCL Print Model 5 27 Filling with Patterns The procedure for applying patterns to text raster images an
133. hree bytes are always one for this mode EC r1A Start raster Ec b1V10110000 Transfer plane 1 the first bit for each pixel in the first row Each bit controls the red primary Ec b1V01110000 Transfer plane 2 the second bit for each pixel in the row Each bit controls the green primary Ec b1W10101000 Transfer plane 3 the third and final bit for each pixel in the row and move to the next row Each bit controls the blue primary Note that the Ec b W command is used to send the last plane of each row 2 10 Using Color Modes EN EN MODE 3 DIRECT BY PIXEL This mode specifies a pixel as three eight bit components thus the name 24 bit direct color Assuming the RGB color space with the mandatory eight bits per component the underlined bytes below define the first pixel of row two Ec b W row 1 7 0 Ec b W row 2 r7 r0 Ec b W row 3 7 0 Example g g0 07 60 g7 g0 b7 b0 g g0 07 60 In the example below the data in the row transfer commands are shown as two digit hexadecimal numbers for clarity even though the actual data would be byte aligned binary data The example is for a one pixel wide image Ec v6W 00 03 00 08 08 08 Ec r1A Ec b3W 45 06 30 Binary Data for CID command represented in hexadecimal This command sets the color space to RGB the PEM to Direct by Pixel The palette size is ignored The last three bytes must be 8 Start raster The three bytes specify a si
134. ices into a palette this value specifies the number of bits required to access all palette entries n pixel encoding modes 2 and direct this value determines palette size but has no effect on the specification of raster data Byte 3 Number of Bits for Primary 1 This byte is ignored in pixel encoding modes 0 and 1 but affects the black and white references in device dependent color spaces In Device RGB the black reference for primary 1 is set to 0 and the white reference is set to 2 1 where n is the number of bits for primary 1 These references are reversed in Device CMY color space In pixel encoding mode 2 this byte is ignored except in Device RGB and Device CMY color space where it designates the number of data bits needed to specify primary 1 as well as the number of data planes to be sent for primary 1 In pixel encoding mode 3 this byte designates the number of data bits needed to specify primary 1 Using Color Modes Color LaserJet 5 5M DeskJet B 13 A value of 0 defaults the black and white reference values for primary 1 according to the color space Byte 4 Number of Bits for Primary 2 This byte is ignored in pixel encoding modes 0 and 1 but affects the black and white references in device dependent color spaces In Device RGB the black reference for primary 2 is set to 0 and the white reference is set to 2 1 where n is the number of bits for primary 2 These references a
135. ich demonstrate the use of the PCL 5 color commands All commands described in this manual are not necessarily supported by all printers See the PCL 5 Comparison Guide for feature support information for each printer This manual is written primarily for users that are already familiar with PCL 5 printer features For information on using PCL 5 see the PCL 5 Printer Language Technical Reference Manual Manual Organization This manual contains seven chapters and four appendices Chapters 2 through 4 describe command usage for the HP Color LaserJet 4500 and 8500 printers Appendices A through D describe how these functions are achieved on the HP Color LaserJet Color LaserJet 5 5M and the DeskJet 1200C and 1600C printers Chapters 5 through 7 pertain to all the color printers described in this manual A brief description of each chapter is provided below Chapter 1 Color Printing Overview This chapter explains background information about printing color documents using PCL 5 Topics include palettes color selection pixel encoding color modes and color matching Chapter 2 Using Color Modes Chapter 2 defines the color modes and describes how to use them including descriptions of sending color raster data using different pixel encoding modes and color spaces Chapter 3 Using Palettes This chapter describes the palettes associated with the color modes and explains how palettes are created saved and modified Chapter 4 Mo
136. iding one bit for each pixel in a row Each plane builds upon the preceding planes until the pixels in a row are fully defined A pixel is not fully defined until it has received all the planes for that row The planes in a row form index numbers that define a pixel by selecting a palette entry For example an 8 entry palette requires 3 planes 2 8 The underlined bits below compose the index of the color of the third pixel in the first row Ec b V row 1 plane 1 red bi bi b1 bi b1 bi Ec b V plane 2 grn b2 b2 b2 b2 b2 b2 Ec b W plane 3 blue Ec b V row2 plane 1 red 61 b1 b1 bi b1 b1 A 6 Color Printing Overview Color LaserJet 5 5M DeskJet EN EN Encoding by Pixel When encoding by pixel each pixel is fully specified before any bits are sent for the next pixel For example if four bits are needed to define a pixel then every group of four bits in the data stream defines a pixel The underlined c4 c1 group below defines the second pixel in the first row Ec b W row 1 b4 b3 b2 b1 c4 c3 c2 c1 Ec b W row2 b4 b3 b2 61 The table below shows the four PCL options for selecting colors and encoding color raster data Planar Encoding Pixel Encoding Indexed Indexed planar Indexed pixel Selection Direct Direct planar Direct pixel Selection Color Modes There are four PCL 5 color modes Black and White mode Simple Color mode PCL Ima
137. ing HP GL 2 patterns are downloaded using the RF Raster Fill command and applied using the FT Fill Type or SV Screened Vectors commands 5 28 The PCL Print Model EN Pattern ID Area Fill ID Command Note EN The Pattern ID command formerly called Area Fill ID identifies the specific shading cross hatch or user defined pattern This command is also used for rectangular area fill described later in this chapter Ec c G Selecting Shaded patterns Selecting Cross Hatch patterns 1thru2 1 2 shade 1 Pattern 1 3thru 10 3 10 shade 2 Pattern 2 11 thru 20 11 20 shade 3 Pattern 3 21 thru 35 21 35 shade 4 Pattern 4 36 thru 55 36 55 shade 5 Pattern 5 56 thru 80 56 80 shade 6 Pattern 6 81 thru 99 81 99 shade 100 100 shade Selecting User Defined patterns ID number of user defined pattern 1 Not supported on all PCL 5 printers Refer to the PCL Feature Support Matrix in Chapter 1 of the PCL 5 Comparison Guide for specifics Default 0 no pattern Range 0 32767 values outside the range are ignored For rectangular areas the pattern material is determined by both the pattern ID and the value of the Fill Rectangular Area command For other images the pattern material is determined by the pattern ID and the value of the Select Pattern command Figure 5 7 and Figure 5 8 illustrate the HP defined shading patterns and cross hatched patterns respectively T
138. ing section for a description of how the pattern transparency mode affects the rectangular fill area A white fill erases any data placed within the rectangular area regardless of the transparency mode settings However after a white fill erases data within an area data subsequently placed within that area will be visible The PCL Print Model 5 49 Pattern Transparency for Rectangular Area Fill Note Pattern transparency affects how a pattern is applied to the rectangular fill area The pattern and pattern type are selected by the Pattern ID command Fc cstG and the Fill Rectangular Area Ec c P command described earlier in this chapter Source transparency has no effect on the rectangular fill area since the rectangular area is viewed as all 1 s a solid black source image When applying a pattern area fill to the rectangular area the pattern transparency mode affects the final result the same as it does when filling other images or text The pattern transparency mode determines the effect white pixels of the pattern have on the destination for value fields O black fill 2 shaded fill 3 cross hatch fill or 5 current pattern fill of the Fill Rectangular Area command The 0 bits of the fill pattern are either applied opaque or ignored transparent based on the transparency mode setting see Figure 5 12 When a value field of 1 white fill is used pattern transparency mode is always treated as if it were
139. ion under Format Byte 0 on the previous page The PCL Print Model 5 39 User defined Pattern Example This example shows how the user defined pattern command is used to create new patterns For this example a pattern of triangles is used The first step is to design the base pattern triangle in this case using 64 bytes of data The base pattern binary data is shown below 11111111111111111111111111111111 01111111111111111111111111111110 00111111111111111111111111111100 00011111111111111111111111111000 00001111111111111111111111110000 00000111111111111111111111100000 00000011111111111111111111000000 00000001111111111111111110000000 00000000111111111111111100000000 00000000011111111111111000000000 00000000001111111111110000000000 00000000000111111111100000000000 00000000000011111111000000000000 00000000000001111110000000000000 00000000000000111100000000000000 00000000000000011000000000000000 This translates into the following 64 bytes of hexadecimal values ER SOR FF FF FE 3F FF FF FC 1F FF FF F8 OF FF FF FO 07 FF FF 03 FF CO 01 FF FF 80 00 FEF FF 00 00 7F FE 00 00 3F FC 00 00 F8 00 00 OF FO 00 00 07 EO 00 00 03 CO 00 00 01 80 00 5 40 The PCL Print Model EN When using the 300 dpi User Defined Pattern header see Table 5 5 set the eight bytes of header information to
140. ions of each PCL command and has examples demonstrating how the commands are used to manipulate the printer A large portion of the manual is devoted to HP GL 2 the vector based graphics language in PCL 5 printers PCL 5 Comparison Guide This document provides printer specific information on paper handling internal fonts PCL command support and control panel information It identifies feature differences between the various PCL 5 printers and how the printers implement the commands described in the PCL 5 Printer Language Technical Reference Manual Printer Job Language Technical Reference Manual This manual describes PJL the HP printer job language used on many of the Hewlett Packard printers PJL is used for switching printer languages requesting status information changing display messages inquiring about feature settings and other job level functions PCL PJL Technical Quick Reference Guide This booklet is designed to provide quick access to the syntax of each PCL and PJL command The commands are grouped by their function so that those familiar with PCL and or PJL can find the syntax of a specific command without opening the manual Contents PCL 5 Color Technical Reference Manual Inside This Manual iii Manual iv Related Documents uer vi Chapter 1 Color Pri
141. ircle is patterned 5 4 The PCL Print Model EN Source Transparency Mode 0 Transparent Pattern Transparency Mode 0 Transparent Nea a Pattern Source Destination Result Image Source Transparency Mode 0 Transparent Pattern Transparency Mode 1 Opaque WK N Pattern Source Destination Result Image Source Transparency Mode 1 Opaque Pattern Transparency Mode O Transparent WS e Pattern Source Destination Result Image Source Transparency Mode eee Pattern Transparency Mode Opaque NW Pattern Source Destination Image Note The symbol represents the logical operation add In this example the foreground color is black and the default ROP is used Figure 5 3 Effect of Transparency Modes on Images EN The PCL Print Model 5 5 Command Sequence The table below shows the Print Model command sequence for selecting a current pattern and using it to fill a destination image The commands for specifying transparency modes logical operations and patterns are discussed beginning on the following page Foreground color is described in Chapter 3 Operation Comments Download Page Data Prior raster and character data downloaded to the page is considered destination image Select Transparency Modes Ec v N source and or Ec v O pattern Specify the Logical Operation If a logical operation other than the default TSo 252 is desired specify the operation
142. is therefore not specified Byte 15 msb 8 7 Isb 0 Byte 0 Color space Pixel encoding mode 1 2 Bits per index Bits per primary 1 3 4 Bits per primary 2 Bits per primary 3 5 6 Encoding for primary 1 R msw 7 8 Encoding for primary 1 R Isw 9 10 Encoding for primary 1 G msw 11 12 Encoding for primary 1 G Isw 13 14 Encoding for primary 1 B msw 15 16 Encoding for primary 1 B Isw 17 18 Encoding for primary 2 R msw 19 20 Encoding for primary 2 R Isw 21 B 22 Using Color Modes Color LaserJet 5 5M DeskJet EN EN Byte 15 msb 8 7 Isb 0 Byte 22 Encoding for primary 42 G msw 23 24 Encoding for primary 2 G Isw 25 26 Encoding for primary 2 B msw 27 28 Encoding for primary 2 B Isw 29 30 Encoding for primary 3 R msw 31 32 Encoding for primary 3 R Isw 33 34 Encoding for primary 3G msw 35 36 Encoding for primary 3 G Isw 37 38 Encoding for primary 3 B msw 39 40 Encoding for primary 3 B Isw 41 42 Minimum primary 1 value msw 43 44 Minimum primary 1 value Isw 45 46 Maximum primary 1 value msw 47 48 Maximum primary 1 value Isw 49 50 Minimum primary 2 value msw 51 52 Minimum primary 2 value Isw 53 54 Maximum primary 2 value msw 55 56 Maximum primary 2 value Isw 57 58 Minimum primary 3 value msw 59 60 Minimum primary 3 value I
143. ity with previous printers is maintained When the printer is turned on it has a 2 entry palette containing the color white at index 0 and black at index 1 When the printer is reset with an cE it reverts to this mode Simple Color mode is entered with the Simple Color command which creates one of three fixed color palettes e monochrome two entry palette with white at index 0 and black at index 1 1 6 Color Printing Overview EN EN e An RGB eight entry palette with the following colors starting at index 0 black red green yellow blue magenta cyan and white e A CMY eight entry palette with the following colors starting at index 0 white cyan magenta blue yellow green red and black PCL Imaging mode is entered with the Configure Image Data command that creates a programmable palette of a programmed size This palette can be programmed using the color component and set index commands HP GL 2 Imaging mode is entered when HP GL 2 mode is entered and the initialize command IN creates a programmable palette that is shared between PCL and HP GL 2 Any and all of the modes can be used on a page For example you could enter the Simple Color mode to print a headline and bar chart PCL imaging mode to print a photographic image and Black and White mode for the text on the page Each mode is described in more detail in Chapter 2 Using Color Modes PCL 5 Raster Images Monochrome PCL 5 raster images are
144. ixels for 49 through 100 and all four pixels between 0 and 48 see the illustration below which represents a halftone cell for one of the primary colors note that the color data is in RGB values Modifying Output Color Color LaserJet 5 5M DeskJet D 9 Sample 2 x 2 Halftone Cell representing one of the primary colors y N SP 205 255 153 204 101 152 RGB Data CMY Data 255 0 48 The halftone cell data defines the thresholds for the various pixel combinations Each dither matrix must be completely specified Otherwise the width and height values may be misinterpreted if multiple matrices are sent If the width height and data specifications result in an odd number data bytes the next matrix specification will begin on an odd byte boundary No padding is provided for even byte aligning Multiple Dither Matrices As noted in the previous table you set the number of planes field to 3 to send separate matrices for each primary Each dither matrix must have its own width and height data fields As shown below the matrix specification for each primary follows the previous primary color s matrix specification D 10 Modifying Output Color Color LaserJet 5 5M DeskJet EN EN Byte 15 msb 7 Isb 0 Byte 0 Format 0 Number of planes 1 2 Dither matrix height in pixels uint 16 3 4 Dither matrix width in pix
145. l 5 47 Fill Rectangular Area The Fill Rectangular Area command determines the type of pattern used to fill the rectangle Ec c P 0 Solid black or foreground color 1 Solid white fill 2 Shaded fill 3 Cross hatch fill 4 User defined pattern fill 5 Current pattern fill Default 0 Range 0 5 out of range values are ignored Note If a foreground color is selected solid shaded and cross hatch patterns are printed in the foreground color User defined patterns are not affected by the foreground color but can contain color if they are defined as such Solid white fills are not affected by foreground color Black fill fills the rectangular area with black fill or with the current foreground color White fill erases any fill in the rectangular area it fills the rectangular area with white fill Pertaining to white fills the pattern transparency mode is always opaque that is the white pixels always have an effect on the destination Shaded fill fills the rectangular area with one of eight shading patterns as specified by the Pattern ID command Cross Hatch fill fills the rectangular area with one of the six cross hatched patterns as specified by the Pattern ID command User defined fill fills the rectangular area with custom pattern data as specified by the Pattern ID command and downloaded by the User Defined Pattern command Current Pattern fills the rectangular area with the current patt
146. les the pattern across and down the page This pattern can be applied to any image including rectangular area fill 4 Width Figure 5 9 User Defined Base Pattern Example A user defined pattern may be applied to any image in the same manner as the internal cross hatch or shade patterns EN The PCL Print Model 5 33 Note For efficient memory usage and improved performance it is strongly recommended that user defined patterns should be 8x8 16x16 or 32x32 in size Specification of patterns that are either 1 pixel in height or width is strongly discouraged If user defined halftones are also used they need to be either the same size or multiples of each other to avoid render anomalies due to each pattern being rendered differently across the page if tiled or due to variations in xy position How the Printer Tiles a Pattern A user defined base pattern is a rectangular binary pattern stored in the printer To apply the pattern to an image area on the page the printer duplicates the base pattern across and down the page This process is referred to as tiling The pattern is only applied to those areas on the page for which the pattern is required 5 34 The PCL Print Model EN Left Printable Area Boundary Left Logical Page Boundary Top of Physical Page Logical Page Default Pattern Reference Point 0 0 Top gt gt Margin To Logical Page Boundary
147. level for HP Color LaserJet 5 and 5M printers B 24 Using Color Modes Color LaserJet 5 5M DeskJet EN Examples Using the CID Command The following examples illustrate using the CID command s short and long forms for each color space For clarity data is shown as ASCII rather than binary and the CID command Ec v W is shown as CID The following format is used CID data data Device RGB or Device CMY SHORT FORM CID 0 1 8 8 8 8 Device RGB 8 bits pixel indexed CID 1 1 8 8 8 8 Device CMY 8 bits pixel indexed Example The short form CID command as a C function can look like this short cid Color mode Pixel mode Bitsperlndex BitsperColor 1 BitsperColor 2 BitsperColor 3 int Color mode Pixel mode Bitsperlndex BitsperColor 1 BitsperColor 2 BitsperColor 3 printf 033 v6W c c c c c c Color_mode Pixel mode Bitsperlndex BitsperColor 1 BitsperColor_2 BitsperColor 3 LONG FORM CID 0 1 8 8 8 8 Device RGB 8 bits pixel indexed 0 0 0 White reference 100 100 100 Black reference Using Color Modes Color LaserJet 5 5M DeskJet B 25 CIE L a b SHORT FORM CID 3 3 0 8 8 8 LONG FORM CID 3 3 0 8 8 8 0 0 100 0 100 0 100 0 100 0 100 0 L a b direct 8 bits primary L a b direct 8 bits primary L data encoding a data encoding b data encoding Non Linear SMPTE RGB 2 2 Gamma 1 0 Gain SHORT FORM CID 2 3 0 8 8 8 LONG FORM CID 2 3 0 8 8 8 0 64 0 3
148. longer a need to provide color adjustments in the printer driver to account for alternate types of RGB data sRGB is the native color space of monitors the default color space of the World Wide Web the default space of many digital cameras and scanners This treatment indicates that the printer should be ready to accept sRGB data This is the preferred mode of operation to provide a good appearance match between the monitor and the printed document The table below lists the driver configuration commands for both color treatments The device id and function index arguments after the c o3W such as 643 should actually be entered as ASCII coded decimal For example instead of 643 you would actually enter the ACK control code followed by the EOT and ETX control codes Treatment Command LJ 4500 Other Color LaserJet Family printers Vivid Graphics Ec o3W843 Ec o3W643 Screen Match Ec o3W846 Ec o3W646 Modifying Output Color 4 5 Finish Mode Command The Finish Mode command allows the user to specify the finish matte or glossy to be applied to the document A normal page has a matte finish Glossy finish can be requested to be applied to the page as it s printed The finish is distinct from the type of media Therefore a matte finish can be requested for glossy media and a glossy finish can be requested for plain or matte paper Ec amp bitF 0 Matte finish 1 Glossy finish Default Range 0 0 1 co
149. lookup tables can remap palette colors to compensate for unwanted color characteristics of input data For example if a scanned photograph had a reddish cast a color lookup table could be used to make the printed image look as if it were taken under a more balanced light source Gamma correction provides a way to adjust for color differences in display monitors The Viewing llluminant command allows you to vary the xy chromaticity coordinates for the light source under which you will be viewing a printed piece For example if the printed document is to be viewed under a tungsten light the command modifies colors so that they have the correct appearance when illuminated by a tungsten light bulb The Monochrome Print Mode command converts each color to its grayscale equivalent for faster draft printing Modifying Output Color Color LaserJet 5 5M DeskJet D 1 The Driver Configuration command provides a way for a driver to calibrate the output by adjusting color lightness saturation and color map information All of these methods of modifying output color are explained in the following sections D 2 Modifying Output Color Color LaserJet 5 5M DeskJet EN Halftone Render Algorithms The HP color printers have the capability of applying different halftone render algorithms to achieve the desired output on the printed image Render algorithms allow you to change the characteristics of the image by changing the way pixels
150. lor LaserJet 5 5M DeskJet EN EN Setting Description MapID Out of Gamut Cluster DutOfGamut DD 17 Disperse OutOfGamut DD 18 Scatter OutOfGamut DD 19 ErrorDiffusion OutOfGamut DD 20 CIELab Match Cluster TrueMatch DD 21 Disperse TrueMatch DD 22 Scatter TrueMatch DD 23 ErrorDiffusion TrueMatch DD 24 Modifying Output Color Color LaserJet 5 5M DeskJet D 25 Setting Description MapID Device Independent No Cluster No Adjust DI 51 Disperse No Adjust DI 52 Scatter No Adjust DI 53 ErrorDiffusion No Adjust DI 54 Process Blue Cluster Process Blue DI 55 Disperse Process Blue DI 56 Scatter Process Blue DI 57 ErrorDiffusion Process Blue DI 58 Transparency Cluster Transparency DI 59 Disperse Transparency DI 60 Scatter Transparency DI 61 ErrorDiffusion Transparency DI 62 Vivid Cluster VividGraphics DI 63 Giaphics Disperse VividGraphics DI 64 Scatter VividGraphics DI 65 ErrorDiffusion VividGraphics DI 66 Out of Gamut Cluster OutOfGamut DI 67 Disperse OutOfGamut DI 68 Scatter OutOfGamut DI 69 ErrorDiffusion OutOfGamut DI 70 CIELab Match Cluster TrueMatch DI 71 Disperse TrueMatch DI 72 Scatter TrueMatch DI 73 ErrorDiffusion TrueMatch DI 74 D 26 Modifying Output Color Color LaserJet 5 5M DeskJet EN EN Index A adaptive compression block size 6 28 6 31 compression me
151. lor blue using the Foreground Color command and then send some text to the printer the text will be printed blue Color Raster Data Unlike page marking primitives each pixel of a color raster image contains color information A color raster pixel may be defined by either Palette Entry Indices Direct Color Specifications User defined color patterns are a form of color raster but each pixel of a user defined color pattern can be defined only by palette entry indices not by direct color specifications A 14 Color Printing Overview Color LaserJet 5 5M DeskJet EN EN Color Processing Functions Given these two color uses page marking primitives and color raster data color processing must Convert color attributes to an internal representation that can be poured through the page marking stencil onto the destination via some logical operation Convert multiple bit per pixel color raster to an internal representation that can be merged into the destination via some logical operation Color processing must have access to the following state variables which indicate the form and attributes by which the two color groups are generated Halftone rendering algorithm RGB gamma correction Device dependent color lookup tables for each of the three primaries Appendix B describes in more detail how color raster data is specified Color Printing Overview Color LaserJet 5 5M DeskJet A 15 A 16 Color
152. lor command Ec r1U This mode creates an unmodifiable default 2 pen palette with white at index 0 and black at index 1 compatible with existing monochrome PCL 5 printers Simple Color Mode Simple Color Mode entered by the Simple Color command amp c r U creates a fixed size fixed color unmodifiable palette Depending on the value field Ec ritU can create a 2 pen Black and White palette an 8 pen RGB palette or an 8 pen CMY palette When using the Simple Color mode the pixel encoding mode is always indexed planar Using Color Modes 2 1 PCL Imaging Mode PCL Imaging Mode enabled by the Configure Image Data command Ec v W allows a maximum of 24 bits per pixel for color specification Therefore more colors may be specified than are obtainable in Simple Color Mode In the PCL Imaging Mode pixel encoding mode bits per pixel bits per primary and the color palette are all programmable HP GL 2 Imaging Mode In HP GL 2 the Initialize IN command starts color imaging and performs the following Sets the pixel encoding mode to index by plane Sets bits per index to 3 Creates an 8 pen palette that is reprogrammable in either PCL or HP GL 2 contexts see Chapter 3 Using Palettes for more information Although default HP GL 2 palettes are different than default PCL palettes an HP GL 2 palette is modifiable in either PCL or HP GL 2 using the Assign Color Index Fc vstl or Pen Color PC commands res
153. lutions cover more picture area per pixel For example a 75 dpi pixel contains 0 0002 square inches a 600 dpi pixel contains 0 000003 square inches Some printing and scanning devices specify a resolution in the horizontal direction and another resolution in the vertical direction 300 by 600 dpi for example However PCL raster only supports identical resolutions in the horizontal and vertical directions and therefore PCL 5 raster graphics pixels are squares Raster Graphics 6 1 There is a direct connection between the resolution and the size of an image The image size is the number of pixels in the image multiplied by the number of bits used to represent a pixel The smaller the dpi the smaller the size of the image the larger the dpi the larger the size of the image There is a tradeoff in image size versus print quality Larger pixels give poorer print quality since diagonal lines can start looking ragged or pixelated but the image size is small Smaller pixels give good print quality but larger image size As a rule 150 dpi provides a happy medium of good print quality at a relatively small image size A printer has a printing resolution 600 dpi for example An image with an image resolution smaller than the printer s resolution will undergo a process of scaling as the image is converted to the printer s resolution also known as device resolution For example a 150 dpi image is converted to a 600 dpi image at device resolution b
154. lways transferred between HP GL 2 and PCL contexts Since only one palette at a time can be active a new palette created in either context overwrites the current palette Using Color Modes Color LaserJet 5 5M DeskJet B 3 Simple Color Mode The Simple Color command amp c r U specifies color selection from a fixed palette RGB or CMY raster data must be sent by plane Ec b V as well as by row Ec b W The last plane in each row is sent using the Fc b W command all other planes are sent using the Ec b V command In Simple Color mode the pixel encoding mode is always indexed planar Simple Color Command The Simple Color command creates a fixed size palette whose color specification cannot be modified Ec r U 3 3 planes device CMY palette 1 Single plane K Black palette 3 Splanes device RGB palette Default 1 Range 3 1 3 The absolute value of the value field specifies the number of planes per row of raster data to be sent The number of entries in the new palette is 2 with index values 0 to 2 1 For example a 3 plane palette has 8 entries with index numbers 0 to 7 This command destroys the active palette and creates a new palette which becomes the active palette When the Simple Color mode is active PCL and HP GL 2 commands that modify the palette are locked out NP PC Ec v A Ec v B Ec v C Ec v l When a Simple Color palette is popped from the stack Ec p P it cannot be modified
155. made up of a series of zeros and ones A one indicates that a black dot should be deposited a zero indicates no dot letting the white background show through A one inch wide image with a resolution of 600 dots per inch DPI has 600 consecutive zeros and or ones which represent a horizontal slice through the image starting at the left edge of the image This slice is known as a raster row For an image one inch high and one inch wide at 600 dpi there are 600 hundred rows of 600 zeros and or ones Color raster images follow the same conventions with this major exception the representation of a dot is changed from a single zero or one to a color specification a pixel Pixels and Pixel Encoding Raster images can be thought of as being composed of a series of pixels picture elements In the case of monochrome raster images a pixel is a single bit which takes on a value of zero or one In color images a pixel is essentially a color specification However there are several ways of specifying a color and how the color is specified is called the Pixel Encoding Mode PEM Color Printing Overview 1 7 The PCL 5 color command set supports several Pixel Encoding Modes The PEMs are categorized first by whether the pixel is an index into a palette or a color specification The other PEM categorization is whether the pixel data is divided into planes and transferred one plane at a time or is transferred in sequential order There are four suppo
156. mine the binary value of the ROP used For example suppose you want to use ROP 90 in the CMY color space The binary equivalent of 90 is 01011010 when written in most significant to least significant bit order Looking at the truth table for ROP 90 in Table 5 2 you can see that the only time the page is marked is when the Texture and Destination are both 0 or both 1 However the same result is given by negating each bit of the ROP number 90 to give 10100101 Using the general table for CMY ROPs the rightmost table in Table 5 2 you can plug the bit values from 90 into b7 through bg to obtain the values in the truth table for ROP 90 Similarly using ROP 90 in the RGB color space entails plugging 01011010 in the general table for RGB ROPS the rightmost table in Table 5 1 to obtain the values in the truth table for ROP rgb 90 also in Table 5 1 This process works for any value from 0 to 255 and can be used to determine what will show for any given ROP in either the RGB or CMY color spaces 5 16 The PCL Print Model EN Note Note EN Since PCL logical operations are interpreted in RGB space white 1 black 0 rather than in CMY space white 0 black 1 the results may not be intuitive For example ORing a white object with a black object in RGB space yields a white object This is the same as ANDing the two objects in CMY space It must be remembered that the printer operates in CMY space and inverts the bits To co
157. mmand is ignored for invalid values The finish mode must be set before the first page is marked and applies to all the pages in the document Each document defaults to a matte finish 4 6 Modifying Output Color EN The PCL Print Model Introduction The Print Model feature allows images and characters to be filled with color with any of the printer s predefined shading or cross hatch patterns or with a user defined pattern Images include any raster graphic such as one created with PCL raster graphics commands as described in Chapter 6 Haster Graphics a rectangular fill area as described later in this chapter as PCL Rectangular Area Fill Graphics or characters selected from any font Figure 5 1 illustrates the use of the print model The following definitions are helpful in describing Print Model operation Foreground Pattern Color Note The symbol represents the logical operation add Texture Source Image Destination Image Resulting Image Figure 5 1 Print Model Imaging EN The PCL Print Model 5 1 Pattern The design which is painted through the non white area of the source image onto the destination image The pattern is defined by the Current Pattern Ec v T command It may be a color pattern or a single plane monochrome mask such as the printer s internal predefined shading or cross hatch patterns or a user defined pattern Foreground color is not applied to a user defined color pat
158. more several shortcuts are available to avoid sending data that is really large blocks of zeros Y Offset Padding Padding Raster Width gt Figure 6 1 Raster Area 6 4 Raster Graphics EN EN An image s width and height define the extent of the image that is the number of pixels in a row and the number of rows in the image The following commands and features eliminate the need to send blocks of zero pixel values 1 The Y Offset command can be used to direct the printer to set all the pixel values in the given number of rows to zero 2 If not enough data is sent for all the pixels in a row the remaining pixels are set to zero 3 If the image is ended before all rows have been received the values of the pixels in the remaining rows will be set to zero Furthermore if too much data is sent the data extending outside the raster area is clipped and discarded Raster Graphics 6 5 Raster Graphics Command Sequence PCL raster commands include Start Raster Graphics and End Raster Graphics commands Transfer Raster Data by Plane and Row Raster Compression Raster Presentation Raster Resolution Raster Height and Raster Width which define the raster area and Raster Y Offset commands For printing well behaved raster graphics the normal sequence of execution for these commands is shown below Hewlett Packard strongly recommends that developers use this command sequence in their applica
159. n 8 pen palette in Device CMY color space All of these Simple Color palettes are fixed and non programmable Single Plane value z 1 Index Color 0 White 1 Black 3 Plane RGB value z 3 Index Color 0 Black k Red Green Yellow Blue Magenta Cyan N White Using Palettes Color LaserJet 5 5M DeskJet C 11 3 Plane CMY value 3 Index Color White Cyan Magenta Blue Yellow Green Red A O N Black C 12 Using Palettes Color LaserJet 5 5M DeskJet EN CID Color Palettes The Configure Image Data command explained in detail in Appendix B creates a palette based upon the parameters in its data field CID created palettes are programmable any entry can be reassigned a different color using PCL commands Ec v A Fc vitB Ec v C Ec v l or HP GL 2 commands CR PC NP Default palettes vary by color space Device RGB Palettes The black and white references specified by the CID command have no effect on the default palettes below However when a CID palette entry is reprogrammed with a different color the black and white references are used to specify the primary components of the new color Bits Index 1 Index Color 0 White 1 Black Bits Index 2 Index Color 0 Black 1 Red 2 Green 3
160. nates waste by providing a draft mode Monochrome Print Mode Command The Monochrome Print Mode command designates whether to print using the current rendering mode or a fast gray scale equivalent Pages printed using the gray scale equivalent do not use any color and therefore print faster and more economically Ec amp b M 0 Printin mixed render algorithm mode 1 Print using gray scale equivalent Default 0 Range 0 1 command is ignored for invalid values This command must be sent prior to printable data otherwise the current page is closed and printed It may be sent on a page by page basis D 20 Modifying Output Color Color LaserJet 5 5M DeskJet EN Driver Configuration Command This command specifies the Lightness Saturation and Scaling Algorithm to be applied to the document and allows for the selection and downloading of Color Maps Ec ostW device id function index Arguments Specifies the number of bytes to follow device ID function index arguments Default N A Range see description below device id Value Printer 6 Color LaserJet printer function index function Description Argument Range index 0 Lightness 100 to 100 1 Saturation 100 to 100 3 Scaling 0 Pixel Replication Aligarh 1 Bilinear Interpolation 2 Modified Bilinear Interpolation 4 Select Color 0 No Adjustment 1 Process Blue Vivid Graphics Transparency Out of G
161. ndependent color to match the color to a Sony Trinitron monitor while operating out of a device dependent color space This setting is supported only by HP Color LaserJet 5 and 5M printers Modifying Output Color Color LaserJet 5 5M DeskJet D 23 Note For screen matching the long form of the Configure Image Data command is used and the color maps are generated internally dependent upon the monitor calibration data the Driver Configuration command is not needed Download Color Map The printer supports the downloading of color adjustment maps dependent upon the halftone requested the type of color treatment desired including device dependent or independent and the type of media Setting Description Device Dependent No adjustment Cluster No Adjust DD Disperse No Adjust DD Scatter No Adjust DD ErrorDiffusion No Adjust DD Process Blue Cluster Process Blue DD Disperse Process Blue DD Scatter Process Blue DD ErrorDiffusion Process Blue DD Transparency Cluster Transparency DD oO Disperse Transparency DD Scatter Transparency DD ErrorDiffusion Transparency DD A Vivid Graphics Cluster VividGraphics DD A C5 Disperse VividGraphics DD 4 Scatter VividGraphics DD ErrorDiffusion VividGraphics DD o D 24 Modifying Output Color Co
162. nge 0 to 32767 command is ignored for out of range values The ID number specified by this command is saved as the palette control ID and is used by the Palette Control command Ec amp p C EcE or power up resets the palette control ID to 0 which is then the default black and white palette ID Macros affect the palette control ID value as follows Calling a macro saves the value and restores the value at exit Executing a macro does not save the value changes remain in effect at exit e Overlaying a macro copies the value before resetting to 0 and restores at exit 3 8 Using Palettes EN Palette Control Note EN The Palette Control command provides a mechanism for making and deleting palettes Ec amp p C 0 Delete all palettes except those in the stack active palette deleted 1 Delete all palettes in the stack active palette is not affected 2 Delete palette specified by Palette Control ID 6 Copy active palette to ID specified by Palette Control ID Default 0 Range 0 1 2 6 command is ignored for unsupported values A value of 0 deletes all palettes except those on the palette stack The active palette is replaced by the default black and white palette ID 0 The palette control ID is not used A value of 1 clears the palette stack The active palette is unaffected and the palette control ID is not used A value of 2 deletes the palette with the specified palette control I
163. ngle pixel The first sets 45 as the red component s value the second sets the green value to 06 and the third sets the blue value to 30 Byte 2 Number of Bits per Index This command creates a palette regardless of the PEM chosen This byte determines the size of the created palette The palette size is two raised to the power of n 2 where n is the bits per index Inthe Indexed by Plane PEM where the raster data is interpreted as palette indices this value determines the number of planes required per row Using Color Modes 2 11 Inthe Indexed by Pixel PEM where the raster data is interpreted as palette indices this value determines how to interpret the byte ordered row transfers The following list shows how each byte is translated into indices Bits Index Indices Byte 1 8 2 4 4 2 8 1 Inthe Direct by Plane and Direct by Pixel PEMs byte 2 does not apply to the raster format Bytes 3 4 and 5 No of Bits for Components 1 2 and 3 These bytes are ignored for the Indexed by Plane and Indexed Direct PEMs For the Direct by Plane PEM they must be set to one bit per component For the Direct by Pixel PEM they must be set to eight bits per component 2 12 Using Color Modes EN HP GL 2 Imaging Mode EN The HP GL 2 Imaging Mode provides a way of using vector commands in printing documents Although the default PCL and HP GL 2 palettes are not the same when transferring from PC
164. ngle number which is then used as an index into the current palette 1 8 Color Printing Overview EN EN Well Behaved Raster PCL raster images are processed most efficiently when the height and width of the image are specified before the Raster Start command begins an image data transfer Furthermore the entire image should be transferred before using the End Raster command to end the image If the image is broken into pieces certain print artifacts such as lines or squares can appear in the image These can occur when nearest neighbor operations are applied to pixels that appear to be at the edge of an image but are really inside an image that has been artificially broken up into smaller images Color Printing Overview 1 9 1 10 Color Printing Overview EN EN 2 Using Color Modes Introduction The PCL printer language has four color modes Black and White Simple Color PCL Imaging HP GL 2 Imaging PCL allows you to use any mode or combination of modes to accomplish your printing objectives most efficiently All four of the color modes create a palette The palette for each mode is discussed in the section describing that mode and also in Chapter 3 Using Palettes Black and White Mode Default Black and White Mode is the default color mode PCL devices power up in this mode and revert back to it whenever the printer receives an ECE reset Black and White mode is also selectable using the Simple Co
165. nsigned byte Byte 15 msb 8 7 Isb 0 Byte 0 Format 0 Number of planes 1 1 2 Dither matrix height in pixels uint 16 3 4 Dither matrix width in pixels uint 16 5 6 byte 0 ubyte byte 1 ubyte 7 8 byte 2 ubyte byte 3 ubyte 9 D 8 Modifying Output Color Color LaserJet 5 5M DeskJet EN Format This byte should be set to 0 Number of Planes This byte designates how many dither matrices are specified by the command The command is ignored and the data discarded for any value other than 1 or 3 Byte Value Value Description 1 One matrix applied to all primaries 3 Each primary has a separate matrix Height and Width These bytes designate the size of the dither matrix in pixels For example a value of four for height and six for width produces a dither cell that is four pixels wide by six pixels high Values must be non zero and sized so the matrix contains no more than 32767 bytes Otherwise the command is ignored and the data discarded The minimum dither matrix size is 1 x 1 Data Bytes After specifying the height and width of the cell data bytes are sent row by row row major order Each data byte contains the normalized probabilities ranging from 0 to 255 of one cell For example a 2 x 2 cell could have no pixels print for RGB values of 205 through 255 one pixel for values of 153 through 204 two pixels from 101 through 152 three p
166. nting Overview INTOGUCUION PEE 1 1 Working with color documents 1 2 PCL 5 Color 1 1 3 iS eee Oui be eek duque 1 3 Color Specifications and Color Spaces 1 3 Color Management and the Standard Red Green Blue Color Space 1 4 Palettes and Color 1 6 PCL 5 Color Graphics 1 6 PCL 5 Color Mode x cde cae eee dex bog dob a ee eee ee CR 1 6 PCL 5 Raster ImageS 0 0 ccc cee teens 1 7 Pixels and Pixel Encoding llis 1 7 Well Behaved 1 9 Chapter 2 Using Color Modes MTOCUCUOM 4 325 EET 2 1 simple Color RE edd bed ee we bed 2 3 PCL Imaging 2 5 Configure Image Data CID 2 5 HP GL 2 Imaging 2 13 Chapter 3 Using Palettes IMTOCUCION EP 3 1 Saving the Palette 2 0 teens 3 3 Push Pop Palette 3 3 Palette Management by ID 3 5 Select Palette Command 3 6 Palette Contr
167. ntinued Boolean Boolean Input Value Function Input Value Function 216 TDSTxax 236 SDTao 217 SDTSaoxn 237 SDTxno 218 DTSDanax 238 DSo 219 STxDSxan 239 SDTnoo 220 STDnao 240 T 221 SDno 241 TDSono 222 SDTxo 242 TDSnao 223 SDTano 243 TSno 224 TDSoa 244 TSDnao 225 TDSoxn 245 TDno 226 DSTDxax 246 TDSxo 227 TSDTaoxn 247 TDSano 228 SDTSxax 248 TDSao 229 TDSTaoxn 249 TDSxno 230 SDTSanax 250 DTo 231 STxTDxan 251 DTSnoo 232 SSTxDSxax 252 TSo 233 DSTDSanaxxn 253 TSDnoo 234 DTSao 254 DTSoo 235 DTSxno 255 1 The PCL Print Model 5 23 Pixel Placement HP PCL 5 printers place pixels at the intersection of the squares of a theoretical device dependent grid covering the printable area on the page Depending on the image and the logical operation in effect a problem may occur when the sides of two polygons touch each other the pixels along the common border may be printed twice or not at all For example a source rectangle consisting of all 1 s that is XORed with a destination consisting of all 1 s produces a white rectangle but if another source rectangle is placed on the page touching the first rectangle the two rectangles will be white filled except at their common border 1 1 1 2 1 To correct situations where this problem occurs the PCL printer language provides a choice of pixel placement models grid intersection and grid centered The grid interse
168. nvert from one color space to the other write the ROP in binary format invert the bits and reverse the order When source and or pattern transparency modes are set opaque not defaulted values specified by this command map directly to the ROP3 raster operation table values on the following page However when source and or pattern transparency modes are set transparent the additional operations shown on the previous page must be performed to achieve the final result Logical operations in the table are shown in RPN reverse polish notation For example the value 225 corresponds to TDSoxn the logical function of NOT texture XOR destination OR source Ec 2 is the PCL Version of the HP GL 2 MC command This command sets the ROP value which affects not only PCL operation but also the HP GL 2 ROP value EXAMPLE The Logical Operation default value is 252 TSo corresponding to a logical function of texture source The PCL Print Model 5 17 The result is computed below source and pattern opaque Table 5 3 Logical Operation ROP3 Bits 7 6 5 4 2 1 0 Texture 1 1 1 1 0 0 0 Source 1 1 0 0 1 1 0 0 Destination 1 0 1 0 1 0 1 0 ROP3 source amp pattern 1 1 1 1 1 1 0 0 decimal 252 Each column of destination source and texture values are the input to the logical function The result 252 is the value that would be sent to identify the logical oper
169. o the pixel encoding mode of the data While these methods reduce the amount of data transferred from the host to the printer they do not reduce the memory requirements within the printer While PCL 5 compression methods are based on redundancies at the byte level the pixel encoding mode must be considered when choosing a compression method The direct by pixel mode transfers the three bytes which make up a pixel one after the other Therefore compression formats that depend upon reducing redundancy within a row will not do well since the pixel to pixel redundancy is disguised by the format This is because while two adjacent pixels have a fairly high probability of being identical the probability that the components of a pixel are identical is very small For example consider a raster image whose background is all one color While there are a large number of pixels that are identical the only time the bytes within the pixel will be identical are if the color is a gray somewhere between white and black such as 0 0 0 128 128 128 255 255 255 If the pixel represents a non gray color the bytes within the pixel will not be identical Therefore the only successful compression mode that exploits redundancy between the rows is delta row compression Since the probability that a pixel is the same in the horizontal direction is usually equivalent to the probability that it is the same in the vertical direction the bytes within a pixel
170. oad Pattern command provides the means for downloading the binary pattern data that defines the user pattern Ec c W pattern data Number of pattern data bytes Default 0 Range 0 32767 HP Color LaserJet 8500 extends the range to 0 to 65535 values outside the range are ignored The value field identifies the number of pattern data bytes that follow the Download Pattern command In addition to the binary pattern data there are eight bytes of pattern descriptor header information included in this pattern data The format for a 300 dpi resolution header is shown in Table 5 5 below Table 5 5 User Defined Pattern Header 300 dpi resolution Byte 15 MSB 8 7 LSB 0 Byte 0 Format 0 Continuation 0 1 2 Pixel Encoding 1 Reserved 0 3 4 Height in Pixels 5 6 Width in Pixels 7 8 Pattern image Format Byte 0 This field indicates the downloadable pattern format Format 0 1 bit per pixel black and white or foreground color A 1 bit indicates black or foreground color for a color pattern A 0 indicates either white or transparency depending on the source and pattern transparency modes A 0 cannot be colored Format 1 1 or 8 bits per pixel This format uses the current palette Data is sent pixel by pixel and the bits index field of the pixel encoding byte determines the number of bits defining a pixel 5 38 The PCL Print Model EN
171. ociated with that pen See the CR command description for the range associated with the values If a primary color is outside of the color range defined in the CR command the value is clamped to the color range limits the CR command is not supported by the HP Color LaserJet 4500 or 8500 printers 7 14 Color Vector Graphics HP GL 2 EN The PC command defaults the colors of all pens as shown in the table below The PC pen command defaults the number of pens as shown in the table on the following page for an HP GL 2 palette When color device palettes larger than 8 pens default the first 8 pen colors are as defined for a palette of 8 all remaining pen colors are device dependent If the palette is a non default palette it defaults in accordance with the default palettes in Chapter 4 No of Pens in Palette Pen Number Color 2 NP 2 0 White 1 Black 4 NP 4 0 White 1 Black 2 Red 3 Green 8 NP 8 0 White 1 Black 2 Red 3 Green 4 Yellow 5 Blue 6 Magenta 7 For black and white printers that accept color descriptions and palettes pen 0 defaults to white all remaining pen colors default to equivalent gray levels An equivalent gray level means that lighter colors for example yellow are converted to light gray shades and darker colors for example purple are converted to dark gray shades The mapping algorithm is device de
172. ol ID esanean ia a ia a a a aea a i a aaa aa a ia a aa aeran acana ar a 3 8 Palette Control essu as au ce ee ea da n E E ee ee 3 9 Simple Color 3 11 EN Contents vii CID Color Palettes 0 0 0 0 0 0 RR RR RR ns 3 13 Device RGB and sRGB Palettes 3 13 Device CMY Palettes 3 14 HP GL 2 Palettes esse recie zum ore ee eb dea bed es de 3 15 Foreground Color 3 17 Foreground Color Command 3 17 Programming Color 3 19 Chapter 4 Modifying Output Color Introduction x cera eem ex hk ERAS E MERE ba 4 1 Halftone Render Algorithms 4 2 Render Algorithm Command 4 2 Monochrome Printing sei arsi ieran en a a e a E eh 4 3 Monochrome Print Mode 4 3 Driver Configuration 4 4 Finish Mode 4 6 Chapter 5 The PCL Print Model INTFOQUCTION zu nse ce bait bee Lene b Re dede eae ead ERE x 5 1 Command 5 5 6 Sour
173. olor Palettes EN The Simple Color command Fc rstU provides a quick way to select colors from a fixed non programmable palette The Simple Color command overwrites the current palette with one of the fixed palettes below When the Simple Color command is in effect the PCL and HP GL 2 commands that modify a palette entry NP PC Ec v A Ec v B Ec v C Ec v Ec t l are locked out A popped simple color palette cannot be modified and the pixel encoding mode reverts to index by plane Only the IN or the CID Ec v W commands can create a modifiable palette As shown below a value field of 1 Fc r1U creates a black and white palette A value of 3 creates an 8 pen palette in Device RGB color space A value of 3 creates an 8 pen palette in Device CMY color space All of these Simple Color palettes are fixed and non programmable Single Plane value z 1 Index Color 0 White 1 Black 3 Plane RGB value z 3 Index Color 0 Black k Red Green Yellow Blue Magenta Cyan NIO a A N White Using Palettes 3 11 3 Plane CMY value 3 Index Color White Cyan Magenta Blue Yellow Green Red A O N Black 3 12 Using Palettes EN CID Color Palettes EN The Configure Image Data command explained in detail in Chapter 2 creates a palette based
174. on this enables end users to enjoy the benefits of color management without the overhead of larger files Application developers and users who do not want the overhead of embedding profiles in documents or images should convert them to sRGB While it may be that profiles buy slightly higher color accuracy the benefits of using a standard color space far outweigh the drawbacks for a wide range of users The migration of devices to support the standard color space SRGB natively will further enhance the speed and quality of the user experience The international standard color space sRGB IEC 61966 2 1 is designed to complement current color management strategies by enabling a simple robust method of handling color in the operating systems device drivers and the Internet This solution provides good quality and backward compatibility with minimum transmission and system overhead Based on a calibrated colorimetric RGB color space well suited to cathode ray tube CRT displays flat panel displays television scanners digital cameras and printing systems the sRGB color space can be supported with minimum cost to software and hardware vendors The four major technical components of the sRGB color space are the standard CRT primaries HDTV P22 phosphors the simple gamma value of 2 2 a D65 white point and its well defined viewing conditions Color Printing Overview 1 5 Palettes and Color Selection The PCL 5 language allows the user to
175. onent 1 Index 4 5 256 Color Component 1 Index 255 Color Component 1 Index 256 257 258 Color Component 2 Index 1 Color Component 2 Index 2 259 260 Color Component 2 Index 3 Color Component 2 Index 4 261 512 Color Component 2 Index 255 Color Component 2 Index 256 513 514 Color Component 3 Index 1 Color Component 3 Index 2 515 516 Color Component 3 Index 3 Color Component 3 Index 4 517 768 Color Component Index 255 Color Component Index 256 769 EN Modifying Output Color Color LaserJet 5 5M DeskJet D 15 Byte 0 Color Space Value Color Space 0 Device RGB default 1 Device CMY Colorimetric RGB Spaces CIE L a b 2 3 4 Luminance Chrominance Spaces A color lookup table can be attached to one or more of the color spaces anytime after a CID command For example a Luminance Chrominance space can have four lookup tables specified namely Device Dependent space CIE L a b space Colorimetric RGB space Luminance Chrominance space A reset ECE IN or CID command sets each of the four levels of color lookup tables for each primary to the unity curve D 16 Modifying Output Color Color LaserJet 5 5M DeskJet EN Gamma Correction Note EN Color monitors which are by nature non linear appear incorrect when given a linear ramp of some color Gamma correction can significantly improve perceptual correctness by adjusting the brightness or darkness of the color da
176. ons causing colors to appear differently under one light source compared to another For example printed colors that look normal in natural sunlight shift in hue when viewed under fluorescent and tungsten lighting The PCL language allows the user to compensate for the differences in viewing illumination using the Viewing Illuminant command It allows the user to select different illuminations Color Printing Overview Color LaserJet 5 5M DeskJet A 13 Processing Color Documents To process a color page PCL provides ways of specifying and modifying color so that the printed result appears as the user desires This section provides a conceptual overview of the process Non Raster Color vs Raster Color All color portions of a page consist of either Page Marking Primitives non raster data Color Raster Data Page Marking Primitives Non raster data consists of HP GL 2 and PCL page marking primitives such as glyphs rules polygons circles and vectors Page marking primitives contain no color information about the image They merely mark the page with attributes assigned to the current working environment for example colors patterns logical operation modes etc Page marking primitives act as stencils through which color paint is poured forming a homogeneous pattern Page marking primitives print in the currently specified color which is specified using the Foreground Color command For example if you specify the co
177. ons of the Line Attribute LA and Line Type LT commands in the PCL 5 Printer Language Technical Reference Manual The number of pens is defaulted by an IN command This command is ignored if the current palette was created by the Simple Color command Fc rstU or EcE 7 18 Color Vector Graphics HP GL 2 EN CR Color Range Note EN The CR command sets the range for specifying relative color data This command is only supported by the HP Color LaserJet Color LaserJet 5 5M and DeskJet printers It is not supported by the HP Color LaserJet 4500 or 8500 printers CR b ref red w ref red b ref grn w ref grn b ref blue w ref blue Parameter Format Functional Parameter Range Default b ref red clamped real 32768 to 32768 0 green blue w red clamped real 32768 to 32768 255 green blue Relative color is in reference to a range defined by a black and white reference value for each primary red green and blue For example if the white reference is set as red 63 green 63 blue 63 and the black references are set as red 0 green 0 and blue 0 then white 63 63 63 black 0 0 0 and medium blue 0 0 31 However if the white reference is set as red 63 green 127 blue 31 and the black reference is set as red 4 green 0 and blue 0 then white 63 127 31 black 4 0 0 and medium blue 4 0 15 The first two parameters set the black and white r
178. opaque The effect of transparency modes on rectangular areas is illustrated in Figure 5 12 In both examples the source transparency mode is opaque regardless of the actual setting In the first example the pattern transparency mode is transparent the white pixels in the pattern are not applied to the destination so that the pattern is visible in only two quadrants of the destination In the second example the pattern transparency mode is opaque and the pattern is visible in the entire rectangular area 5 50 The PCL Print Model EN Source Transparency Mode or 1 Transparent or Opaque Pattern Transparency Mode O Transparent 7 Pattern Rectangular Destination Result Area Source Transparency Mode or 1 Transparent or Pattern Transparency Mode Opaque M Pattern Retangular Destination Result Area This example is a monochrome example and assumes the default ROP Figure 5 12 Effect of Transparency Modes on Rectangular Areas EN The PCL Print Model 5 51 Rectangular Fill Examples Following are two examples that demonstrate the way to print and fill rectangular shapes The first example demonstrates filling rectangles with solid fill and the second example demonstrates filling with a shading pattern Solid Fill Black White To print a 900 by 1500 Unit black rule 3 inches by 5 inches at 300 units per inch then white fill a small area inside the black rectangle perform the foll
179. or treatment mode to use for rendering the next job D 22 Modifying Output Color Color LaserJet 5 5M DeskJet EN EN No Adjustment This setting provides linearization only that is the user sees the device as a linear device Process Blue This setting provides the same results as Vivid Graphics linearization plus user preferred enhancements with the addition of mapping process blue which looks slightly purple to a blue closer to that of a standard monitor This setting is not supported by HP Color LaserJet 5 and 5M printers Vivid Graphics This setting adds color saturation to the resulting image Transparency This setting uses a map to render the best color output on transmissive media This setting is not supported by HP Color LaserJet 5 and 5M printers Out of Gamut This setting prints colors in an image that are out of gamut all colors that are in gamut snap to white all out of gamut colors are snapped to the gamut surface This setting only supports the device independent color map This setting is not supported by HP Color LaserJet 5 and 5M printers CIE L a b Match This map performs a true color match to the requested CIE L a b input there are no appearance matching adjustments This setting only supports the device independent color map This setting is not supported by HP Color LaserJet 5 and 5M printers Screen Match This setting produces a simulated Colorimetric RGB effect of device i
180. owing steps 1 Position the cursor Ec p300x400Y This moves the cursor to PCL Unit position 300 400 within the PCL coordinate system Specify the width of the rule Ec c900A This sets the rule width to 900 PCL Units 3 inches at 300 units per inch Specify the height of the rule Ec c1500B This sets the rule height to 1500 PCL Units 5 inches at 300 units per inch Print the rule Ec cOP This example prints a black filled rectangular area Position the cursor inside the rectangular area Ec p600x700Y Specify the width and height for the smaller white fill rectangular area Ec c300a600B 5 52 The PCL Print Model EN 7 Select the white fill and print Ec c1P 300 400 600 700 Figure 5 13 Solid Fill Example EN The PCL Print Model 5 53 Shaded Fill To print a 900 by 1500 Unit 25 shaded rectangle 3 inches by 5 inches at 300 units per inch perform the following steps 1 Position the cursor Ec p300x400Y This moves the cursor to PCL Unit position 300 400 within the PCL coordinate system 2 Specify the width of the rectangle Ec c900A This sets the rectangle width to 900 PCL Units 3 inches at 300 units per inch 3 Specify the height of the rectangle Ec c1500B This sets the rectangle to 1500 PCL Units 5 inches at 300 units per inch 4 Specify the Pattern ID Ec c25G This sets the Pattern ID to 25 5 54 The PCL Print Model EN 5 Print the rectangular shaded area
181. pe Portrait Default Graphics Margin logical page left bound logical page left bound logical page left bound logical page left bound logical page left bound logical page left bound 50 dots in from the logical page top bound 50 dots in from the logical page top bound Eh umm MOH 191S H Reverse Portrait X Print Direction Mode O amp Mode 3 1 left graphics margin cursor position prior to the raster data transfer Figure 6 3 EN Raster Graphics Presentation Mode for Portrait Orientation Raster Graphics 6 11 Landscape MOH Je SeH Landscape Print Direction O Mode O Print Direction O Mode 3 1 left graphics margin e Y1 cursor position prior to the raster data transfer Figure 6 4 Raster Graphics Presentation Mode for Landscape Orientation 6 12 Raster Graphics Reverse Landscape E a a g e Reverse Landscape EN Source Raster Height Command Note Note EN The Raster Height command specifies the height in raster rows of the raster area Height is the direction perpendicular to the direction that raster rows are laid down hence height is subject to the current raster presentation mode and print direction see Figure 6 5 Ec r T Height raster rows Default N A Range Oto logical page length current Y position of the 0 cursor Greater values default to logical page length
182. pectively Likewise a PCL palette created by the Configure Image Data command Fc vitW is modifiable in both PCL and HP GL 2 using the same commands The active palette is always transferred between HP GL 2 and PCL contexts Since only one palette at a time can be active a new palette created in either context overwrites the current palette 2 2 Using Color Modes EN Simple Color Mode The Simple Color command amp c r U specifies color selection from a fixed palette RGB or CMY raster data must be sent by plane Ec b V as well as by row Ec b W The last plane in each row is sent using the Fc b W command all other planes are sent using the Ec b V command In Simple Color mode the pixel encoding mode is always indexed planar Simple Color Command The Simple Color command creates a fixed size palette whose color specification cannot be modified Ec r U 3 3 planes device CMY palette 1 Single plane K Black palette 3 3planes device RGB palette Default 1 Range 3 1 3 This command destroys the active palette and creates a new palette which becomes the active palette When the Simple Color mode is active PCL and HP GL 2 commands that modify the palette are locked out NP PC Ec v A Ec vstB Ec v C Ec v l When a Simple Color palette is popped from the stack Ec p P it cannot be modified and the pixel encoding mode reverts to indexed planar A value field of 1 creates a 2 entry Black and White
183. pendent However equivalent gray levels represent solid colors and any white pixels within them are not subject to transparency mode TR Color Vector Graphics HP GL 2 7 15 Note In the shading Fill Type command FT10 the shading levels are mapped between white 096 shading and the equivalent gray level for the currently selected pen 100 shading In the HP GL 2 user defined Fill Type command FT11 each pixel in the RF pattern is rounded to white or black based on the equivalent gray level of the pen number for that pixel This rounding should use a low enough white black threshold so that yellow will round to black For a black and white device pen 0 defaults to white all remaining pen colors default to black This command is ignored if the current palette was created by the Simple Color command Fc ritU An IN command defaults pen colors as indicated in the previous table 7 16 Color Vector Graphics HP GL 2 EN NP Number of Pens EN The NP command resizes the palette after the IN or Ec v W commands NP n or NP Parameter Format Functional Parameter Range Default n clamped 2 to 32768 device dependent integer The default palette size for the HP color printers is 8 n the parameter n denotes the size of the HP GL 2 palette where n is a power of two If n is not a power of two the next larger power of two is used The palette is an array of virtual pens each
184. pped to the printable area Raster Graphics 6 7 Raster Graphics Resolution Command Raster graphics can be printed at various resolutions This command designates the resolution of subsequent raster data transfers in dots per inch Ec t R 75 75 dots per inch 100 100 dots per inch 200 200 dots per inch 150 150 dots per inch 300 300 dots per inch 600 600 dots per inch Default 75 Range 75 100 150 200 300 600 This command must be sent prior to the start graphics command The factory default resolution is 75 dots per inch Note Lower resolution graphics occupy less user memory For example the number of bits required to represent a two inch by three inch image at 75 dots per inch is 33 750 The same image at 300 dots per inch requires 540 000 bits Note that lower resolution graphics may not give acceptable print quality When configured for 300 dpi resolution the printer automatically expands raster graphics transferred at resolutions less than 300 dots per inch to 300 dots per inch during printing Figure 6 2 illustrates how a single bit is translated into the corresponding printed dots in various graphics resolutions when the printer is configured for 300 dpi 6 8 Raster Graphics EN 2 6e 300 dpi ey 150 dpi 1 dot X Reference Position Figure 6 2 Raster Graphics Expansion at 300 dpi Note Rectangular area fills and character data are not affected by changes in resolution Rec
185. r Palettes of colors can be referenced by an ID and so can PCL color graphic states At any given time there is an active palette to apply colors from along with a render algorithm and color treatment to be applied to the colors Palettes and their associated render algorithm and color treatment can be stored and retrieved using a palette ID When a palette is retrieved and made the active palette the render algorithm and color treatment stored with the palette are set as the current render algorithm and color treatment 1 2 Color Printing Overview EN The PCL language also allows users to use patterns in combination with colors These patterns and colors can be combined with text vector graphics and images to create new complex graphics objects The PCL Print Model determines the logical operations known as ROPs Raster Operations used to combine each part of the graphic object PCL 5 Color Concepts This section describes some of the concepts and terminology of color science related to the PCL 5 color commands Color Color is a combination of human physiological and psychological responses to a relatively narrow band of frequencies in the electromagnetic spectrum The frequencies visible to the human eye are called the visible spectrum It s useful to understand that color comes both from direct light and indirect light that has reflected from a surface Reflected light absorbs all but the reflected frequency The colors seen on
186. r amp Pattern Temporary ROP3 ROP3 Dest Src Texture Image A Temporary ROP3 amp Src Image B Dest amp Not Src RETURN Image_A Image B e Case 4 Source and Pattern are transparent Texture Color amp Pattern Temporary ROP3 ROP3 Dest Src Texture Image A Temporary ROP3 amp Src amp Pattern Image B Dest amp Not Src Image C Dest amp Not Pattern RETURN Image A Image B Image C The Transparency Mode is applied based on the color of each pixel However the Logical Operation is applied on a bit by bit basis without regard to color In order to obtain a result consistent with the Logical Operation the transparency modes should be set to Source Opaque and Pattern Opaque In order to obtain a result consistent with the desired transparency mode the Logical Operation should be set to 252 and the foreground color set to black 5 12 The PCL Print Model EN Logical Operation Command Specifies the logical operation ROP to be performed in RGB color space on destination source and texture to produce new destination data Texture is defined as a combination of pattern and foreground color Ec Logical operation value see Table 5 4 Default 252 TSo Range Oto 255 The Logical Operation code or Raster OPeration ROP code is simply a systematic method of encoding all of the 256 possible ways that a Texture Source and Destination can be combined Table 5 4 gives a table of RO
187. r Data by Plane command is used to send each plane in the row except the last the Transfer Raster Data by Row command Ec b W must be used to send the last plane and advance the cursor to the beginning of the next row Transfer Raster Data by Row This command Fc b W moves the current active cursor position to the next pixel row after its execution It is used for monochrome printers for the last plane in a multi plane row or for color raster transfer when the data is encoded by pixel Both commands are described in detail in the following paragraphs Chapter 2 provides additional descriptions and examples using the Transfer Raster Data commands to print color images 6 32 Raster Graphics EN Note EN Transfer Raster Data by Plane This command sends a plane of data to the printer and advances to the next plane not to the next row Ec b V raster data Default N A Range 0 to 32767 The value field identifies the number of bytes in the plane The number of planes per row is specified by the Simple Color command Ec r U or the Configure Image Data command Ec v W depending on which color mode is used The first plane sent represents the least significant bit in the pixel Since Ec b V does not advance the cursor to the beginning of the next raster row it cannot be used for the last plane or for single plane rows Only Ec b W can advance the cursor to the next row The amount of data sent varies from plane
188. r Range CR Note The IN command always establishes the 8 pen palette Two Pens Pen Number Color 0 White 1 Black Four Pens Pen Number Color 0 White 1 Black 2 Red 3 Green C 16 Using Palettes Color LaserJet 5 5M DeskJet EN EN Eight Pens Pen Number Color White Black Red Green Yellow Blue Magenta Cyan Black Using Palettes Color LaserJet 5 5M DeskJet C 17 Foreground Color All PCL marking entities utilize foreground color which is selected from the current palette using the Foreground Color command Ec v S Foreground color interacts with raster color depending on the print model commands in effect Foreground Color Command The Foreground Color command sets the foreground color to the specified index of the current palette Ec v S Index number into current palette Default 0 Range Oto current palette size _ 4 Specified values that are out of range of the current palette are mapped into a new index as follows Index Specified foreground index modulo palette size For example specifying a foreground color index of 10 when the current palette size is 8 maps to 10 modulo 8 which is equal to 2 If the current palette was created under HP GL 2 the index is mapped according to the HP GL 2 mapping function Foreground color affects the following PCL page marking primiti
189. r Space This byte specifies the color space The range of values is 0 through 4 All other values are ignored Byte Value Color Space 0 Device RGB default Device CMY Colorimetric RGB Spaces CIE L a b RR oO N Luminance Chrominance Spaces EN Using Color Modes Color LaserJet 5 5M DeskJet B 7 Note Note Colorimetric RGB color spaces are based on the 1931 standard 2 degree observer and specified by CIE xy chromaticity coordinates They use the standard D6500 viewing illuminant and a 45 degree illumination model with a O degree collector geometry for reflective data CIE L a b is the CIE 1976 Uniform Color Space based on the 1931 standard 2 degree observer and using a 45 degree illumination model with a 0 degree collector geometry for reflective data The viewing illuminant is the standard D6500 illuminant Luminance Chrominance spaces are a 3x3 linear transformation from Colorimetric RGB Like CIE L a b achromatic data is contained in one channel and chromatic data shares the other two channels HP Color LaserJet 5 and 5M printers parse and discard the CID command when Colorimetric RGB spaces are specified Rather than creating a Colorimetric RGB palette a device RGB palette is created but it is populated with the default color of the Colorimetric RGB palette In addition the ScreenMatch color table is selected to give the impression of Colorimetric RGB behavior while working
190. r printers offer two methods for selecting colors Indexed selection Direct selection In indexed selection colors are chosen using their palette index numbers For non raster mode the palette index number is specified using the Foreground Color command In raster mode the data bit combination for each pixel forms an index number The example below shows how the index numbers for an 8 color palette are specified Three bit combinations 01010101 00110011 00001111 Palette index number 01234567 Color Printing Overview Color LaserJet 5 5M DeskJet A 5 The number of colors in the palette dictates the number of bits per pixel of raster data required to specify an index number For example to specify 256 colors you need to send 8 bits of raster data per pixel 28 256 In direct selection colors are specified using the proportions of their primary components For example using a 24 bit per pixel representation the color specified by Oxff OxfO 0x00 for red green and blue would print a slightly red tinted yellow A palette is not used for direct selection Pixel Encoding Colors are encoded in a row of raster data using either plane or pixel format In planar format all the pixels in a row are partially specified by one plane bit before the next plane is sent In pixel format each pixel is fully specified before sending the next pixel Encoding by Plane Planar encoding uses successive data planes each prov
191. rarely useful since it applies only to the direct by pixel PEM where the format must be eight bits per component for 24 bit direct color and the direct by plane where there is one bit per component Ec v6W b0 b1 b2 b3 b4 b5 Where b0 bi b2 b3 b4 b5 The number of bytes following the W byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 The color space The Pixel Encoding Mode The number of bits per index which implies the size of the palette The number of bits in color component primary 1 The number of bits in color component primary 2 The number of bits in color component primary 3 Using Color Modes 2 5 The bytes are ordered as follows and are unsigned bytes Byte 15 MSB 8 7 0 LSB Byte 0 Color space Pixel encoding mode 1 2 Bits index Bits primary 1 3 4 Bits primary 2 Bits primary 3 5 Invalid configurations of the CID command are ignored and the data discarded A minus or a plus sign in the value field 6 or 6 is ignored The data fields in the command bytes zero to five must contain byte aligned binary data not ASCII data Byte 0 Color Space This byte specifies the color space The range of values is 0 through 2 All other values are ignored Byte Value Color Space 0 Device Dependent RGB default 1 Device Dependent CMY 2 Standard RGB sRGB Color space 2 SRGB was the designation for Colorimetri
192. re color gamut of both devices However it also involved the overhead of transporting the profile of the input device with the image and running the image through the transform 1 4 Color Printing Overview EN Note EN HP s ICC profiles are available through normal HP software distribution channels For those who want the additional control available through building their own ICC profiles there are several vendors of profiling tools available To provide access to the printer s pure primaries and entire available printer gamut the Vivid mode may be used when profiling the printer and subsequently when using the ICC workflow However there are a broad range of users that do not require this level of flexibility and control in an embedded color profile mechanism Instead it is possible to define a single standard default color space for exchange and interpretation of color data Additionally most existing file formats do not support color profile embedding and may never do so There is also a broad range of uses that actually discourages people from appending any extra data to their files The sRGB color space addresses these issues The sRGB color space maintains the advantage of a clear relationship with ICC color management systems while minimizing software processes and support requirements Since the image is in a known color space and the profile for that color space is included within the operating system and display applicati
193. re reversed in Device CMY color space In pixel encoding mode 2 this byte is ignored except in Device RGB and Device CMY color spaces where it designates the number of data bits needed to specify primary 2 as well as the number of data planes to be sent for primary 2 In pixel encoding mode 3 this byte designates the number of data bits needed to specify primary 2 A value of 0 defaults the black and white reference values for primary 2 according to the color space Byte 5 Number of Bits for Primary 3 This byte is ignored in pixel encoding modes 0 and 1 but affects the black and white references in device dependent color spaces In Device RGB the black reference for primary 3 is set to 0 and the white reference is set 2 1 where is the number of bits for primary 3 These references are reversed in Device CMY space In pixel encoding mode 2 this byte is ignored except in Device RGB and Device CMY color space where it designates the number of data bits needed to specify primary 3 as well as the number of data planes to be sent for primary 3 In pixel encoding mode 3 this byte designates the number of data bits needed to specify primary 3 A value of 0 defaults the black and white reference values for primary 3 according to the color space B 14 Using Color Modes Color LaserJet 5 5M DeskJet EN Note Note EN Short Form of CID Command Configure Image Data The Short Form of the CID
194. red and the seed row is zeroed For Method 3 delta row compression within an adaptive compression block the seed row is updated by every raster compression method or type of row For example a row compressed with Method 2 TIFF updates the seed row while the effect of an empty row initializes the seed row to zeros Maintaining the seed row allows Method 3 to be mixed with other methods to achieve optimal compression performance Raster Graphics 6 31 For Method 3 since delta row compression requires that the seed row be available whenever raster graphics mode is entered the seed row is initialized to zeros upon raster graphics mode entry Ec r A The seed row is also initialized upon receipt and completion of each raster block For Method 3 if the row length terminates the data before the control byte value is satisfied literal byte count greater than row length the data following the control byte if any is printed as text The cursor is incremented For Method 3 f the row length is equal to one the current row is duplicated and the cursor is incremented Transfer Raster Data Commands There are two Transfer Raster Data commands Transfer Haster Data by Plane and Transfer Raster Data by How Transfer Raster Data by Plane This command Fc b V is used when the raster data is encoded by plane as specified by the Simple Color command Ec r U or the Configure Image Data command Fc v W The Transfer Raste
195. red for other values For value fields 2 4 and 5 the Pattern ID Ec c G command is sent prior to the Pattern Control command to identify the specific pattern to which the Pattern Control command action is applied 5 44 The PCL Print Model EN Rectangular Area Fills Rules Note EN Rectangular area fills are a special case of source images the source transparency mode has no effect since the printer treats the rectangular area as a solid black all 1 s source Rectangular areas may be filled using patterns or textures The current Pattern ID Ec c G selects the pattern and the Fill Rectangular Area command tiles an area whose dimensions are specified by the Vertical and Horizontal Rectangle size commands Ec c B Ec c H The rectangular area does not exist and cannot be printed until the Fill Rectangular Area command has been issued even though the rectangular area has been specified Filling a rectangular area does not change the current active cursor position CAP The filled rectangular area is not affected by end of line wrap perforation skip mode or margins A rectangular area may extend beyond the margins but it will be clipped to the printable area of the logical page Rectangular areas are not affected by graphics resolution Ec t R Except for the absence of white pixels in the source pattern transparency operates the same way for rectangular area fills a
196. ression 6 20 Transfer Raster Data command 6 32 6 33 Width command 6 15 zeroed rows 6 5 raster graphics presentation mode command 6 10 raster graphics resolution command 6 8 raster height command 6 13 raster image 6 1 raster mode A 3 raster scaling 6 36 raster vs non raster color A 14 raster width command 6 15 Raster Y Offset command 6 19 rectangle fill transparency mode 5 50 Horizontal Size command 5 46 position 5 49 transparency mode 5 49 Vertical Rectangle Size command 5 47 rectangular area fill examples 5 52 rectangular area fills 5 45 related documents vi render algorithm command 4 2 D 3 render algorithms 4 2 A 2 D 3 resolution raster graphics printing 6 8 ROP 5 13 ROP3 logical operation 5 13 rows zeroed in raster graphics 6 5 rule black 5 32 white 5 32 rules 5 45 run length adaptive compression 6 29 raster graphics compression 6 20 S scaling raster 6 36 Seedrow 6 24 6 26 adaptive compression 6 31 raster graphic termination 6 17 Select Current Pattern command 5 32 Select Palette command 3 6 C 6 Set Compression Method command 6 20 EN Set Pattern Reference Point command 5 33 5 43 shaded fill pattern selection 5 29 patterns 5 30 short form CID command B 15 Simple Color command 2 3 B 4 simple color mode 2 1 2 3 B 2 B 4 source image 5 2 Source raster height command 6 13 source raster width command 6 15 Source transparency mode 5 2 Source Transparency Mode command 5 7 SP 6 13 sRGB color space
197. rint The maximum value for these two bytes is 65 535 however the image is clipped to the logical page Thus the value of these bytes should not exceed the maximum number of bytes rows that can be printed on the current logical page size If an out of range command byte is encountered the remainder of the block is skipped the cursor is not updated and the seed row is cleared Compression methods 0 3 are the compression methods used by the Set Compression Method command Value fields 4 and 5 are features for the adaptive compression method and are explained below Empty Row A command byte of 4 empty row causes a row of zero s to be printed The number of rows printed depends on the value contained in the two lt of bytes rows gt bytes following the command byte The empty row operation resets the seed row to zero and updates the cursor position Duplicate Row A command byte of 5 duplicate row causes the previous row to be printed again The row can be duplicated the number of times indicated by the value contained in the of bytes row gt byte Duplicate Row updates the cursor position but does not change the seed row 6 30 Raster Graphics EN Note EN Adaptive Compression Operation Hints Some HP LaserJet printers perform internal compression techniques to support full page graphics Refer to Chapter 1 of the PCL 5 Comparison Guide for specifics The compression methods cannot be mixed within one raster
198. rinted output are transformations that map input data into a new output color range based upon point by point conversions Overhead transparencies provide one example of a good use for color lookup tables Let s say a page is printed on plain paper and it matches the user s expectations When printing the same document on overhead transparency film the resulting image looks unsaturated and flat To compensate the user can send a color lookup table to increase color saturation without changing composition for example using the CIE L a b color space to increase the a and b parameters in equal amounts Color lookup tables can also be used to adjust data from a Kodak CD ROM which uses the Photo YCC device independent color space The gamma correction table is complex and cannot be described by the traditional logarithmic expression However since the data can be mapped into new data values via tables the user can provide a gamma correction table that essentially describes the complex correction factors Color lookup tables can be used to neutral balance an image For example an underwater photograph produces a severe bluish cast when printed The user can eliminate that cast from the image by providing a color lookup table that subtracts some color portion from each of the primaries A 12 Color Printing Overview Color LaserJet 5 5M DeskJet EN EN Illumination Models Illumination sources have different spectral distributi
199. ritU palette entries can be modified The three primary components of a color are specified and the resulting color is assigned to the palette entry indicated by Fc vstl In the explanation below the term component refers to the color space primary colors For example if the current color space is CIE L a b component 1 indicates CIE L component 2 indicates CIE a and component 3 indicates CIE b Color Component One This command specifies the first primary of the palette entry designated by the Assign Color Index command Ec v l Ec v A First Component Default 0 Range 32767 0000 to 32767 0000 up to 4 decimal places command is ignored for invalid configurations The Assign Color Index command actually applies this value and then resets it to 0 Color Component Two This command specifies the second primary of the palette entry designated by the Assign Color Index command Ec v B Second Component Default 0 Range 32767 0000 to 32767 0000 up to 4 decimal places command is ignored for invalid configurations The Assign Color Index command actually applies this value and then resets it to 0 C 20 Using Palettes Color LaserJet 5 5M DeskJet EN Color Component Three This command specifies the third primary of the palette entry designated by the Assign Color Index command Ec v C Third Component Default 0 Range 32767 0000 to 32767 0000 up to 4 decimal places
200. rsion of the PCL Logical Operation command This command sets a ROP value which affects not only HP GL 2 operation but also the PCL ROP value The MC command is defaulted by an IN command 7 6 Color Vector Graphics HP GL 2 EN Opcode Specifies the logical operations performed on a source destination and pattern prior to drawing the final image These raster opcodes ROPs are listed on the following pages in reverse polish notation RPN using the following abbreviations D Destination S Source T Texture a and n not Or X exclusive or For example when mode 0 the opcode default is 252 which is the logical function TSo Texture OR Source The operation code opcode specifies the logical operations that are performed on a source destination and patterned image prior to drawing the final image The opcodes are created by listing all possible combinations of a single pattern source and destination pixel and constructing the desired final pixel values The following table shows three common opcodes constructed by reading the output values bottom up Pixel Combinations Desired Destination Values Patter Pixel Source Pixel Destination Source Transparency Source Pixel Overwrite TR command Destination 0 0 0 0 0 0 0 0 1 0 1 1 0 1 0 1 1 1 0 1 1 1 1 0 1 0 0 0 0 0 1 0 1 0 1 1 1 1 0 1 1 1 1 1 1 1 1 0 Resulting Opcode 204 0xCC 238
201. rted Pixel Encoding modes 1 Indexed by Plane 2 Indexed by Pixel 3 Direct by Plane 4 Direct by Pixel also known as 24 bit direct For example the format known as direct by plane uses a 3 bit pixel where the first bit indicates the presence or absence of a red dot the second a green dot and the third a blue dot The data is still arranged in rows but all the red data is sent then the green and finally all the blue The example below represents the commands to transfer an image with the direct by plane PEM The underlined bits while transferred separately are logically from the same pixel Ec b V 1 plane 1 red bi bi bi bi bi Ot Ec b V plane 2 green b2 b2 b2 b2 b2 b2 Ec b W plane blue b3 b3 Ec b V 2 plane 1 red b1 bi bi bi bi bt The direct by pixel PEM uses only the row transfer command Each pixel is composed of three bytes one byte per component of the color specification All the bytes of a given pixel are transferred before the next one is transferred Ec b W row x bi b2 b3 bi b2 b3 bl The indexed by pixel PEM is similar to the direct pixel PEM but the pixel occupies at most one byte and is an index into the current palette The indexed by plane PEM is similar to the direct by plane PEM except the pixel s value is an index into the current palette The use of this mode is discouraged due to the extra processing required to combine the bits from each plane into a si
202. s descriptions of sending color raster data using different pixel encoding modes and color spaces Appendix C Using Palettes Color LaserJet 5 5M DeskJet Appendix C describes the use of palettes for the HP Color LaserJet 5 and 5M and DeskJet 1200C and 1600C printers It explains the palettes associated with the color modes and explains how palettes are created saved and modified Appendix D Modifying Output Color Color LaserJet 5 5M DeskJet Appendix D describes how to modify output color for the HP Color LaserJet Color LaserJet 5 5M and the DeskJet 1200C and 1600C printers This chapter explains how color can be optimized by compensating for different conditions such as variations in color due to light sources limitations of the original artwork and variations in viewing monitors The chapter details the use of halftone rendering algorithms color lookup tables gamma correction and viewing illuminant commands These commands are provided so that users can request and receive color output that matches their expectations Index An index offers quick access to PCL command information Related Documents vi The following documents provide related information about Hewlett Packard PCL 5 printers PCL 5 Printer Language Technical Reference Manual The PCL 5 Printer Language Technical Reference Manual provides a description of the printer command language that controls PCL 5 printers The manual provides explanat
203. s for other sources The non white pixels of the pattern are poured through the entire rectangular area onto the destination The white bits of the pattern are either applied or ignored based on the pattern transparency mode If foreground color is used it is applied to the non white bits of the pattern prior to pouring except for user defined color patterns The Pixel Placement command Fc R affects rules The commands used to print rectangular area fills are described beginning on the next page The PCL Print Model 5 45 Horizontal Rectangle Size PCL Units This command specifies the horizontal rectangle size in PCL Units Ec c A number of PCL Units valid to 4 decimal places The horizontal rectangle size is clipped to the bounds of the logical page Values greater than the logical page boundary are acceptable however the final output is limited to the printable area of the logical page Values outside the range of 0 32767 are ignored The default rectangle size is 0 Power up and reset return this value to the default Horizontal Rectangle Size Decipoints This command specifies the horizontal rectangle size in decipoints Ec c H number of decipoints valid to 4 decimal places The horizontal rectangle size is clipped to the bounds of the logical page Values greater than the logical page boundary are acceptable however the final output is limited to the printable area of the logical page Values out
204. sent To reassemble the raster data rows the printer takes the current row the seed row and makes the changes indicated by the delta data to create the new row The new row which becomes the new seed row is used by the next delta compression data to create another row A delta compression row consists of two parts a command byte and the replacement bytes as shown below Command byte 1 to 8 Replacement bytes 6 24 Raster Graphics EN The command byte identifies two things 1 the number of replacement delta bytes that follow and 2 where to position the replacement byte string the left offset The replacement bytes are some number up to eight bytes of consecutive bytes that are used to create the new row from the seed row 7 5 4 0 Number of bytes to replace 1 8 Relative offset from last untreated byte If more than eight replacement delta bytes are needed additional command byte replacement bytes may be added as shown below Ec 3m W Command Byte 1 to 8 Replacement Bytes Command Byte 1 to 8 Replacement Bytes In the command byte the upper three bits identify the number of replacement delta bytes which can be 1 to 8 bytes The lower five bits identify the location the replacement bytes are to be positioned This position is identified as the offset or the number of bytes from the treated byte For example if there are 5 replacement bytes and the offset is 7 then the replac
205. serJet 5 5M DeskJet EN Example Ec v6W 00 01 04 04 04 04 Ec r1A Ec b1W45 Ec b1W6A Ec b1W03 MODE 2 DIRECT BY PLANE Binary data for CID represented in hexadecimal Sets color space to RGB pixel encoding mode to 1 palette size to 16 4 bits to address palette index Last 3 bytes ignored Start raster Most significant nibble selects palette index 4 for the first pixel Second pixel is set to index 5 Move to the next row First pixel is index 6 second pixel is index 10 Move to the next row First pixel is index 0 second pixel is index 3 Move to the next row In mode 2 the color raster data for each row is downloaded by sequential planes but the pixel color is directly specified rather than forming an index into the palette The underlined block below defines the actual primaries for pixel 3 of row 1 Ec b V row 1 red plane Ec b V green plane Ec b W blue plane Ec b V row 2 red plane oOo gt c OQ r 9 b r uo Using Color Modes Color LaserJet 5 5M DeskJet B 11 Example Ec v6W 00 02 01 01 01 01 Binary data for CID represented in hex Sets color space to RGB pixel encoding mode to 2 Palette size is ignored because this is a direct selection not indexed Last 3 bytes are always 1 for this mode Ec r1A Start raster Ec b1V10110000 Transfer plane for primary color 1 Each bit turns on or off the red primary for the pixel d
206. serJet 5 and 5M printers The white point is based on the standard D6500 illuminant Byte 15 msb 8 7 Isb 0 Byte 0 Color space Pixel encoding mode 1 2 Bits per index Bits per primary 1 3 4 Bits per primary 2 Bits per primary 3 5 6 Minimum L value most significant word 7 8 Minimum L value least significant word 9 10 Maximum L value msw 11 12 Maximum L value Isw 13 14 Minimum a value msw 15 16 Minimum a value Isw 17 18 Maximum a value msw 19 20 Maximum a value Isw 21 22 Minimum b value msw 23 24 Minimum b value Isw 25 26 Maximum b value msw 27 28 Maximum b value Isw 29 Using Color Modes Color LaserJet 5 5M DeskJet B 19 FLOATING POINT FORMAT The following format is used for device independent color floating point specifications 31 30 23 22 0 Sign Exponent Fractional Portion The above single precision 32 bit floating point specification is fully compliant with the IEEE Floating Point Formats Colorimetric RGB Long Form The long form for Colorimetric RGB allows specifications other than the default non linear SMPTE RGB with a 2 2 gamma and 1 0 gain Each RGB primary and the white point is specified in the CID data field by chromaticity coordinates CIE xy The tristimulus luminance Y value of the white point is assumed to be 100 and is therefore not specified For color sp
207. set of 1 byte from the current position The replacement byte follows and contains 11111111 Row 2 Fc b2W 00000010 11110000 The first three bits of the command byte indicate that one byte will be replaced and the next five bits indicate a relative offset of 2 so the replacement will occur 2 bytes from the current position The replacement byte follows and contains 11110000 Row 3 Ec b5W 00000000 00001 111 00100010 10101010 10101010 As in the other rows the first three bits of the command byte are zero indicating a single byte replacement The five offset bytes indicate a relative offset of zero bytes The replacement byte follows and is 00001111 The third byte is another command byte and the first three bits signify the replacement of two bytes the top three bits are 001 The offset bits indicate an offset of two bytes from the current position The fourth and fifth bytes are the two replacement bytes Adaptive Compression Method 5 Adaptive compression enables the combined use of any of the four previous compression methods 0 through 3 and it includes the ability to print empty all zeros rows or to duplicate rows Adaptive compression interprets a raster image as a block of raster data rather than as individual rows The result of this interpretation is that the Transfer Raster Data Ec b W command is sent only once at the beginning of a raster data transfer and the value field identifies the number of
208. side the range of 0 32767 are ignored Decipoints are converted into printer dot values and any fraction of a dot is rounded up to the next full dot size The default rectangle size is 0 Power up and reset return this value to the default 5 46 The PCL Print Model EN Vertical Rectangle Size PCL Units This command specifies the vertical rectangle size in PCL Units Ec c B number of PCL Units valid to 4 decimal places The vertical rectangle size is clipped to the bounds of the logical page Values greater than the logical page boundary are acceptable however the final output is limited to the printable area of the logical page Values outside the range of 0 32767 are ignored The default rectangle size is 0 Power up and reset return this value to the default Vertical Rectangle Size Decipoints This command specifies the vertical rectangle size in decipoints Ec c V number of decipoints valid to 4 decimal places The vertical rectangle size is clipped to the bounds of the logical page Values greater than the logical page boundary are acceptable however the final output is limited to the printable area of the logical page Values outside the range of 0 32767 are ignored Decipoints are converted into printer dot values and any fraction of a dot is rounded up to the next full printable dot The default rectangle size is 0 Power up and reset return this value to the default The PCL Print Mode
209. signed integers sint16 The short form for the Device RGB color space defaults each primary s black reference to 0 and the white reference to 2 1 where nis the number of bits for that primary Byte 15 msb 8 7 Isb 0 Byte 0 Color space Pixel encoding mode 1 2 Bits per index Bits per primary 1 3 4 Bits per primary 2 Bits per primary 3 5 6 White reference for primary 1 sint 16 7 8 White reference for primary 2 sint 16 9 10 White reference for primary 3 sint 16 11 12 Black reference for primary 1 sint16 13 14 Black reference for primary 2 sint16 15 16 Black reference for primary 3 sint16 17 Using Color Modes Color LaserJet 5 5M DeskJet B 17 Device CMY Long Form The long form for the Device CMY color space value field is 18 provides explicit entry of black and white references range is 32767 to 32767 Black and white references are used in the direct pixel encoding modes 2 3 to set relative limits for raster data they are also used when specifying the primary components of new palette entries Ec v A Ec v B Ec v C Black and white references have no effect on the default CID palette colors The reference values are specified as 16 bit signed integers sint16 Note The short form for the Device CMY color space defaults each primary s white reference to 0 and black reference to 2 1 where n is the number of bits for that primary
210. sw 61 62 Maximum primary 3 value msw 63 64 Maximum primary 3 value Isw 65 66 x Chromaticity for red primary msw 67 68 x Chromaticity for red primary Isw 69 70 y Chromaticity for red primary msw 71 72 y Chromaticity for red primary Isw 73 74 x Chromaticity for green primary msw 75 Using Color Modes Color LaserJet 5 5M DeskJet B 23 Byte 15 msb 8 7 Isb 0 Byte 76 x Chromaticity for green primary Isw 77 78 y Chromaticity for green primary msw 79 80 y Chromaticity for green primary Isw 81 82 x Chromaticity for blue primary msw 83 84 x Chromaticity for blue primary Isw 85 86 y Chromaticity for blue primary msw 87 88 y Chromaticity for blue primary Isw 89 90 x Chromaticity for white point msw 91 92 x Chromaticity for white point Isw 93 94 y Chromaticity for white point msw 95 96 y Chromaticity for white point Isw 97 98 Gamma for red primary msw 99 100 Gamma for red primary Isw 101 102 Gain for red primary msw 103 104 Gain for red primary Isw 105 106 Gamma for green primary msw 107 108 Gamma for green primary Isw 109 110 Gain for green primary msw 111 112 Gain for green primary Isw 113 114 Gamma for blue primary msw 115 116 Gamma for blue primary Isw 117 118 Gain for blue primary msw 119 120 Gain for blue primary Isw 121 Note CIE L a b color space support is at HP Color LaserJet
211. t previews the remaining appendices which describe the specific details of Hewlett Packard color printing The features described in these appendices are a superset of those supported by the HP Color LaserJet Color LaserJet 5 5M and DeskJet printers Some features are supported on one or more printers but not necessarily on all of them See the PCL 5 Comparison Guide for specific feature support for each printer Processing a color document involves specifying a palette or palettes and then using the colors within the current palette to print For non raster printing items such as text rules and vectors are simply printed in the currently active color which is specified using the Foreground Color command or Select Pen command if in HP GL 2 For raster printing the color of each pixel is specified as either a direct color specification or as an index into the palette depending on the pixel encoding mode The PCL Print Model determines how color is applied to the page The printed result can vary in background and texture depending on the source transparency mode pattern transparency mode and selected logical operation ROP Besides the pre defined shading and patterns users can define new monochrome or multicolor patterns Color Printing Overview Color LaserJet 5 5M DeskJet A 1 When printing color pages a user can choose one of several color modes depending on the desired results Each color mode has a palette associated
212. t the resultant color is independent of the device Examples of color spaces based on absolute standards include Kodak Photo YCC CIE L a b YUV and the proposed YCrCb Each is a transform from tristimulus CIE XYZ space A 10 Color Printing Overview Color LaserJet 5 5M DeskJet EN With proper calibration any device can provide a transform from device independent color space to the device s own color space producing output from different devices that have the same color appearance For example if a monitor s parameters are known gamma gain chromaticity coordinates for each primary and the white point the monitor s RGB pixel information can be transformed into device independent color The Color LaserJet printers provide device independent color specified using either the CIE L a b Colorimetric RGB or Luminance Chrominance color spaces HP Color LaserJet 5 and 5M printers also provide device independent color specified using either the CIE L a b Colorimetric RGB or Luminance Chrominance color spaces However HP Color LaserJet 5 and 5M printers are somewhat restricted in what they provide Details of this can be found in Appendix D Color Matching When attempting to match color produced by different devices it is important to know the difference between true color matching and appearance matching Proper device calibration can achieve true color matching so that a side by side comparison of a printed page with the
213. tW configures the current palette and specifies a device independent color space 2 Render Algorithm command Ec t J is set to one of the following algorithms see Halftone Render Algorithms in Appendix D for details Continuous tone detail Fc t0J Fc t16J Continuous tone smooth Fc t15J Fc t17J Continuous tone basic Fc t18J Fc t19J Device best dither Ec t3J Fc t5J Error Diffusion Ec t4J Ec t6J A 8 Color Printing Overview Color LaserJet 5 5M DeskJet EN EN e Cluster Ordered Dither Fc t7J Fc t8J Ordered Dither Ec t11J 12 Color processing reverts to device dependent processing if the render algorithm is changed from one of the above This is because extensive device characterization is necessary to achieve device independence calibration must be based on known parameters that affect the device s color gamut Render algorithms such as Snap to Primaries Ec t1J Snap Black to White and Colors to Black Fc t2J or User Defined Halftone Ec t9uJ either limit the number of colors available or are undefined to the extent that their performance is not as precise These algorithms therefore produce device dependent results Device independent color is again generated if the render algorithm changes to one of the 5 listed above and the color space has not changed Color Printing Overview Color LaserJet 5 5M DeskJet A 9 Device Independent Color The PCL language characterizes color
214. ta sent from the monitor to any other non linear device Gamma Correction Command Gamma number Default 0 gamma correction off Range 0 0 to 32767 0 command is ignored for invalid values The practical range for gamma values is 0 0 to 4 0 Assuming 8 bits per primary 256 intensity levels per primary the corrected intensity for each color primary is calculated as follows Intensity 255 Input Y 255 Gamma correction is referred to in terms of device dependent RGB This command does not destroy the contents of device dependent color lookup tables but setting a gamma value supersedes any lookup table input in either Device CMY or Device RGB The default value 0 gives the same result as a gamma value of 1 0 which results in a unity gamma curve Modifying Output Color Color LaserJet 5 5M DeskJet D 17 Viewing llluminant Printed colors undergo a hue shift when viewed under different illuminations for example fluorescent tungsten or daylight Colors with spectral characteristics outside the range of an illumination source are not received changing the appearance of mixed colors The Viewing Illuminant command Ec i W supports communication of standard illuminations to the printer to allow the printer to compensate for different lighting conditions when appearance matching Viewing llluminant Command The Viewing Illuminant command specifies the relative white point used in the determination of
215. tangular Area fills and character data always print at the maximum resolution regardless of the resolution setting EN Raster Graphics 6 9 Raster Graphics Presentation Mode Command The Raster Graphics Presentation command specifies the orientation of the raster image on the logical page Ec r F 0 Raster image prints in orientation of logical page 3 Raster image prints along the width of the physical page Default 3 Range 0 3 6 10 Raster Graphics A value of 0 indicates that a raster row will be printed in the positive X direction of the PCL coordinate system The print direction translates the PCL coordinate system A value of 3 indicates that the raster graphics will be printed along the width of the physical page regardless of logical page orientation In portrait orientation a raster row is printed in the positive X direction of the PCL coordinate system and a subsequent raster row is printed beginning at the next dot row position in the positive Y direction In landscape orientation a raster row is printed in the positive Y direction of the PCL coordinate system and a subsequent raster row is printed beginning at the next dot row position in the negative X direction Figures 6 3 and 6 4 illustrate presentation modes 0 and 3 EN Raster Presentation Mode 0 0 0 0 C5 Orientation portrait reverse portrait landscape reverse landscape portrait reverse portrait landscape reverse landsca
216. tern When printing a page text and raster images are printed using the current pattern Once the current pattern is specified it stays in effect until another is selected or the printer is reset A reset returns the current pattern to its default value 10096 black The current pattern does not always apply to rectangular area fill which uses patterns defined by the rectangular area fill pattern commands Foreground Color Foreground color is selected from the current palette using the Foreground Color command Ec v S Foreground color affects everything except user defined color patterns and HP GL 2 primitives Raster color mixes with foreground color see Chapter 6 Color Raster Graphics Texture Texture is another name for the combination of pattern and foreground color or for a color pattern which is not combined with a foreground color Source Image the Source Image is an image in which the non white bits are replaced by the specified pattern The source image functions like a stencil through which the pattern is applied to the destination image The source image may be one of the following HP GL 2 primitives rules characters or raster images single plane mask or multi plane color Destination Image The image onto which the source image texture combination is placed The destination image includes any images placed through previous operations Source Transparency Mode The transparency or opaqueness o
217. the end of this chapter NS Prem Transparent Pattern This example uses the default ROP The output may appear differently depending on the colors used Figure 5 2 Opaque and Transparency Modes EN The PCL Print Model 5 3 Figure 5 3 demonstrates the transparency modes In the first example 1a the transparency mode for both the source image and the pattern is transparent Since the source mode is transparent only the non white region the circle of the source image is overlaid on the destination Since the pattern mode is also transparent the patterned source image is applied only to the white areas of the destination In the second example 1b the source mode is still transparent but the pattern mode is opaque so the pattern s white pixels are applied to the destination The resulting image shows the entire circle region visible and patterned In the third example 1c the source mode is opaque and the pattern mode is transparent Since the source mode is opaque the entire source image the circle and the surrounding square appears overlaid onto the destination The pattern however is allowed to pour through only onto the white pixeled area of the destination The circle is visible in the result but only two opposing quarters appear patterned In the fourth example 1d both source and pattern modes are opaque The entire source image is overlaid onto the destination and the entire c
218. thods 6 29 control bytes 6 29 cursor position 6 31 data block 6 28 delta row 6 29 6 31 duplicate row 6 29 6 30 6 31 empty row 6 29 6 30 6 31 format 6 29 operation hints 6 31 row length 6 31 run length encoded 6 29 6 31 seed row 6 31 TIFF 6 29 6 31 y offset 6 31 area fill ID command See also pattern ID command 5 29 area fill user defined patterns 5 33 assign color index command 3 20 C 21 base pattern 5 33 black and white references A 4 black rule 5 32 black and white mode 2 1 B 2 block size adaptive compression 6 28 byte counts 6 34 C chapter summary iv CIE L a b color space B 18 clipping raster area 6 13 coding efficiency raster compression 6 23 color concepts A 3 device dependent A 2 A 4 A 10 device independent A 2 A 4 A 10 foreground 3 17 C 18 lookup tables A 12 D 13 map 4 4 D 22 matching A 11 modes A 7 modifying output 4 1 D 1 processing documents A 14 raster vs non raster A 3 A 14 selection A 5 color appearance matching A 12 color component one command 3 19 C 20 color component three command 3 20 C 21 color component two command 3 19 C 20 color lookup tables A 2 color lookup tables command D 13 color management 1 4 color modes black and white mode 2 1 B 2 HP GL 2 imaging mode 2 2 2 13 B 3 B 28 PCL imaging mode 2 2 2 5 B 2 B 6 simple color mode 2 1 2 3 B 2 B 4 color print model command sequence 5 6 logical operations and transparency 5 12 rectangular area fills 5 45
219. tions Note Although the source raster height and width commands are not necessary they improve memory efficiency Well Behaved Raster Command Sequence Raster Presentation Raster Resolution Raster Height Raster Width Start Raster Graphics Y Offset Raster Compression Transfer Raster Data Transfer Raster Data Y Offset Transfer Raster Data Y Offset Raster Compression Transfer Raster Data Raster Compression Transfer Raster Data End Raster Graphics 6 6 Raster Graphics EN Note EN The emphasis in the previous command sequence is that the Raster Presentation Mode Raster Resolution Raster Height and Raster Width are all set outside the start data end sequence of commands Also the entire image is sent during the start data end sequence choosing the most effective compression method for each raster row of data Raster Presentation Raster Resolution Raster Height Raster Width and Raster Compression are all true modes Once specified the printer remains in that mode unless explicitly changed by issuing the command again or reset to default values by a soft reset self test font printout or power cycle Only raster data appearing within the intersection of the logical page the printable area the raster width and height is printed If raster width and or raster height have not been set the intersection of the logical page and the printable area determines where raster graphics appear raster data is cli
220. to tile patterns with respect to the current cursor position CAP This command also specifies whether the pattern rotates with the print direction or remains fixed Ec p R 0 Rotate patterns with print direction 1 Keep patterns fixed Default Range 0 0 1 values outside the range are ignored A value field of 0 rotates the patterns with changes in the print direction see Print Direction command For a value field of 1 patterns remain fixed for changes in print direction The default pattern reference point is the upper left corner of the logical page at the top margin position 0 0 If the Set Pattern Reference Point command is not set the pattern is tiled with respect to the default reference point All patterns are rotated for changes in orientation but the pattern reference point remains the same refer to Logical Page Orientation Command in Chapter 5 of the PCL 5 Printer Language Technical Reference Manual This command applies to user defined shading and cross hatch patterns The PCL Print Model 5 43 Pattern Control Command The Pattern Control command provides a means for manipulating user defined patterns Ec c Q Default Range Delete all patterns temporary amp permanent Delete all temporary patterns Delete pattern last ID specified Make pattern temporary last ID specified Make pattern permanent last ID specified 0 0 1 2 4 5 command is igno
221. two pixel wide image Ec v6W 00 01 04 08 08 08 Binary Data for the CID command represented in hexadecimal This command sets the color space to RGB the PEM to Indexed by Pixel the palette size to 16 2 The last three bytes are ignored EC r1A Start raster Ec b1W45 The most significant nibble selects palette entry 4 for the first pixel The second pixel is set to index 5 Move to next row Ec b1W6A The first pixel is index 6 the second pixel is index 10 Move to the next row Ec b1W03 The first pixel is index 0 the second pixel is index 3 Using Color Modes 2 9 MODE 2 DIRECT BY PLANE In this mode a pixel is composed of three one bit components The data is transferred a plane at a time one plane for each component Therefore each bit in a plane represents one component of a pixel The underlined bits below show the components for a pixel Ec b amp V row plane 1 red b bi bi bi bi bt Ec b V plane 2 green b2 b2 b2 b2 b2 b2 Ec b W plane 3 blue b3 b3 b3 b3 b3 b3 Ec b V row2 plane 1 red 1 bi bi bi bi bt Example In the example below the data in the row transfer commands are shown in binary for clarity even though the actual data would be byte aligned binary data The example is for an eight pixel wide image Ec v6W 00 02 01 01 01 01 Binary Data for the CID command represented in hexadecimal This command sets the color space to RGB the PEM to Direct by Plane The palette size is ignored The last t
222. undancy between rows Other PCL compression modes exploit redundancy within a row With Direct by Pixel the redundancy from pixel to pixel in a row is masked by the differences at the byte level within the pixel that is the differences between the red green and blue bytes within the pixel Raster data in Index by Plane or Direct by Plane modes cannot be compressed using raster compression mode 5 You need one plane or one bit pixel for each power of two colors in the palette For example a 256 color palette requires 8 planes or 8 bits pixel 28 256 Using Color Modes 2 7 PEM 0 INDEXED BY PLANE In Pixel Encoding Mode 0 successive planes of data are sent for each raster row A plane contains one bit for each pixel in a row A pixel is not fully defined until all the planes for that row have been received which is signaled by a transfer raster row command The planes in a row form index numbers into the current palette For example assuming three bits per index the underlined column of bits in the figure below is the palette index for pixel three of the first row i1 is the least significant bit i3 is the most significant bit Note that the Transfer Raster Data by Plane command Fc b V is used for all planes except the last plane of each row which is sent using the Transfer Raster Data by Row command Ec b W Ec bEV 1 plane 1 1 d Wd d Hd d Ec b V plane 2 2 i i i 2 i2 Ec b W plane 3 ia i3 8 8 i3 i3 Ec b V row2 plan
223. upon the parameters in its data field CID created palettes are programmable any entry can be reassigned a different color using PCL commands Ec v A Fc vst B Ec v C Ec v l or HP GL 2 commands PC NP Default palettes vary by color space Device RGB and sRGB Palettes Bits Index 1 Index Color 0 White 1 Black Bits Index 2 Index Color 0 Black 1 Red 2 Green 3 White Bits Index 3 through 8 Index Color 0 Black 1 Red 2 Green 3 Yellow 4 Blue 5 Magenta 6 Cyan 7 White n gt 7 Black Using Palettes 3 13 Device CMY Palettes Bits Index 1 Index Color 0 White 1 Black Bits Index 2 Index Color 0 White 1 Cyan 2 Magenta 3 Black Bits Index z 3 through 8 Index Color 0 White 1 Cyan 2 Magenta 3 Blue 4 Yellow 5 Green 6 Red 7 Black n 7 Black 3 14 Using Palettes EN HP GL 2 Palettes Note EN Regardless of the color space a default PCL palette is always different than a default HP GL 2 palette The following table shows the default palettes established in HP GL 2 Like a default CID palette a default HP GL 2 palette can be modified in either PCL or HP GL 2 contexts using the following commands PCL Color Components 1 2 and 3 Ec v A Ec v C Assign Color Index Ec v l HP GL 2 Number of Pens NP
224. ure 5 4 Logical Operations and the Print Model Note The Logical Operation command 1 provides 255 possible logical operations All of these logic operations map directly to their ROP3 raster operation counterparts see the Microsoft Document Reference Volume 2 Chapter 11 Binary and Ternary Raster Operation Codes The logical operations were defined for Microsoft Windows for an RGB color space In RGB space a 1 is white and a 0 is black EN The PCL Print Model 5 1 1 Note Logical Operations and Transparency Interactions As described above transparency modes operate in addition to logical operations The Logical Operations ROP3 in Table 5 4 are true only if source and pattern transparency for white pixels are explicitly set to opaque Fc v1N and Fc v10O If source and or pattern transparency modes are transparent defaulted the additional operations shown below must be performed to achieve the final result The four basic interactions are Case 1 Source and Pattern are opaque Texture Color amp Pattern RETURN ROP3 Dest Src Texture e Case 2 Source is opaque Pattern is transparent Texture Color amp Pattern Temporary_ROP3 ROP3 Dest Src Texture Image A Temporary_ROP3 amp Not Src Image_B Temporary_ROP3 amp Pattern Image_C Not Pattern amp Src amp Dest RETURN Image A Image B Image C e Case 3 Source is transparent Pattern is opaque Texture Colo
225. value as follows Calling or Overlaying a macro saves the ID value and a copy of the active palette Upon macro exit the restored palette again becomes the active palette with the restored ID An existing palette with this ID is deleted Executing a macro does not save the ID value or the active palette changes remain in effect Using Palettes Color LaserJet 5 5M DeskJet C 7 Palette Control ID The Palette Control ID command specifies the ID number to be used by the Palette Control Command Ec amp p l Palette ID number Default 0 Range 0 32767 command is ignored for out of range values The ID number specified by this command is saved as the palette control ID in the current modified print environment and is used by the Palette Control command Fc amp p C EcE or power up resets the palette control ID to 0 which is then the default black and white palette ID Macros affect the palette control ID value as follows Calling a macro saves the value and restores the value at exit Executing a macro does not save the value changes remain in effect at exit e Overlaying a macro copies the value before resetting to 0 and restores at exit C 8 Using Palettes Color LaserJet 5 5M DeskJet EN Palette Control Note EN The Palette Control command provides a mechanism for marking and deletion of palettes Ec amp p C 0 Delete all palettes except those in the stack active
226. ves Text characters they change to the foreground color including underlining Solid or monochrome patterned rectangular area fills rules Monochrome patterns except HP GL 2 Raster images The following are not affected User defined color patterns format 1 download patterns HP GL 2 marking primitives HP GL 2 uses selected pen but ignores foreground color C 18 Using Palettes Color LaserJet 5 5M DeskJet EN Note EN Foreground color interacts with color raster images In the printer all color raster is resolved into three binary raster planes of CMY Foreground color is applied to these planes modifying the color image For no interaction set foreground color to black when sending color raster images After a foreground color is selected changing any of the following will not change foreground color until a new Foreground Color command Ec v S is issued Active Palette Configure Image Data CID command Render Algorithm User Defined Dither Matrix Gamma Correction Color Lookup Tables Viewing llluminant As an exception Monochrome Print Mode amp 0 immediately maps foreground color to its equivalent gray Similarly deselection of Monochrome Print Mode immediately returns foreground color to its color equivalent Using Palettes Color LaserJet 5 5M DeskJet C 19 Programming Color Palettes Except for the default black and white palette or the Simple Color palettes Fc
227. vice dependent grid covering the page In the grid centered model the number of rows and columns are each reduced by one and pixels are placed in the center of the squares rather than at the intersections The following example illustrates the concepts of the two models Assume a rectangle extends from coordinate position 1 1 to position 3 4 As shown below for the same coordinates the grid centered model produces a rectangle that is one dot row thinner and one dot row shorter than the grid intersection model Thus when two or more polygons on a page share a common border grid centering value 1 can be turned on Since PCL printers print only at the intersections of the grid the actual implementation of the grid centered model is also shown in the following illustration 7 20 Color Vector Graphics HP GL 2 EN Grid Intersection Grid Centered Actual Grid Centered Implementation Figure 7 1 Pixel Placement EN Color Vector Graphics HP GL 2 7 21 Note PP Pixel Placement Command The Pixel Placement PP command controls how pixels are placed on the layout grid during polygon fills The two pixel placement modes are grid intersection or grid centered PP mode Parameter Format Functional Parameter Range Default mode clamped integer or 1 0 grid intersection mode 0 grid
228. ween contexts The current active position CAP is transferred between HP GL 2 and PCL for 1 and Ec 3B only The PCL orientation determines the HP GL 2 orientation In PCL mode the Enter HP GL 2 Mode command must be executed except when in display functions mode or within a binary data transfer HP GL 2 ignores this command Default Settings when Entering HP GL 2 When you enter HP GL 2 mode most vector graphics variables retain their previous HP GL 2 value However the following changes in the PCL environment can affect the HP GL 2 environment Resetting the printer ECE or control panel reset Executes an IN Initialize command Defaults the PCL Picture Frame size Defaults the PCL Picture Frame anchor point Defaults the HP GL 2 plot size Defaults the PCL logical page orientation Apage size page length or orientation command Defaults the PCL Picture Frame anchor point Defaults the PCL Picture Frame Defaults the HP GL 2 plot size Defaults P1 and P2 IP IR commands Resets the soft clip window to the PCL Picture Frame boundaries IW command Clears the polygon buffer PMO PM2 Updates the cursor to the lower left corner of the picture frame P1 7 4 Color Vector Graphics HP GL 2 EN EN Redefining the PCL Picture Frame size or setting the anchor point e Defaults P1 and P2 IP IR commands e Resets the soft clip window IW to the PCL Picture Frame boundaries e Clears the polygon buf
229. with the Fc 2 O command Select Specific Pattern ID Pattern ID Ec c G Download User Defined Pattern If using a user defined pattern it must be downloaded to the printer before using it Select Pattern Ec v4T selects downloaded pattern Specify the Foreground Color For color printers specify a Foreground Color Ec vitS if desired This step is unnecessary if a color pattern is used Download Source Image Data Raster image characters Return to regular print mode Default current pattern and transparency modes Fc vOT 100 black pattern selected and Ec vON Ec v0O transparency modes selected Download remaining page data Transfer data for regular printing or the above process may be repeated to produce another print model effect End of Page Data 5 6 The PCL Print Model EN Source Transparency Mode Command Note EN The Select Source Transparency Mode command sets the source image s transparency mode to transparent or opaque This command determines whether the source s white pixels are applied to the destination Ec v N 0 Transparent 1 Opaque Default 0 Range 0 1 other values cause the command to be ignored With a transparency mode of 0 transparent the white regions of the source image are not copied onto the destination With a transparency mode of 1 opaque the white pixels in the source are applied directly onto the d
230. xTDxaxn 17 DSon 44 STDSoax 18 SDTxnon 45 TSDnox 19 SDTaon 46 TSDTxox 20 DTSxnon 47 TSDnoan 21 DTSaon 48 TSna 22 TSDTSanaxx 49 SDTnaon 23 SSTxDSxaxn 50 SDTSoox 24 STxTDxa 51 Sn 25 SDTSanaxn 52 STDSaox 26 TDSTaox 53 STDSxnox The PCL Print Model 5 19 Table 5 4 Logical Operations ROP3 continued Boolean Boolean Input Value Function Input Value Function 54 SDTox 81 DSTnaon 55 SDToan 82 DTSDaox 56 TSDToax 83 STDSxaxn 57 STDnox 84 DTSonon 58 STDSxox 85 Dn 59 STDnoan 86 DTSox 60 TSx 87 DTSoan 61 STDSonox 88 TDSToax 62 STDSnaox 89 DTSnox 63 TSan 90 DTx 64 TSDnaa 91 DTSDonox 65 DTSxon 92 DTSDxox 66 SDxTDxa 93 DTSnoan 67 STDSanaxn 94 DTSDnaox 68 SDna 95 DTan 69 DTSnaon 96 TDSxa 70 DSTDaox 97 DSTDSaoxxn 71 TSDTxaxn 98 DSTDoax 72 SDTxa 99 SDTnox 73 TDSTDaoxxn 100 SDTSoax 74 DTSDoax 101 DSTnox 75 TDSnox 102 DSx 76 SDTana 103 SDTSonox 77 SSTxDSxoxn 104 DSTDSonoxxn 78 TDSTxox 105 TDSxxn 79 TDSnoan 106 DTSax 80 TDna 107 TSDTSoaxxn 5 20 The PCL Print Model EN EN Table 5 4 Logical Operations ROP3 continued Boolean Boolean Input Value Function Input Value Function 108 SDTax 135 TDSaxn 109 TDSTDoaxxn 136 DSa 110 SDTSnoax 137 SDTSnaoxn 111 TDSxnan 138 DSTnoa 112 TDSana 139 DSTDxoxn 113 SSDxTDxaxn 140 SDTnoa 114 SDTSxox
231. xnon 47 TSDnoan 21 DTSaon 48 TSna 22 TSDTSanaxx 49 SDTnaon 23 SSTxDSxaxn 50 SDTSoox 24 STxTDxa 51 Sn 25 SDTSanaxn 52 STDSaox 26 TDSTaox 53 STDSxnox EN Color Vector Graphics HP GL 2 7 9 Table 7 1 Logical Operations ROP3 continued Boolean Boolean Input Value Function Input Value Function 54 SDTox 81 DSTnaon 55 SDToan 82 DTSDaox 56 TSDToax 83 STDSxaxn 57 STDnox 84 DTSonon 58 STDSxox 85 Dn 59 STDnoan 86 DTSox 60 TSx 87 DTSoan 61 STDSonox 88 TDSToax 62 STDSnaox 89 DTSnox 63 TSan 90 DTx 64 TSDnaa 91 DTSDonox 65 DTSxon 92 DTSDxox 66 SDxTDxa 93 DTSnoan 67 STDSanaxn 94 DTSDnaox 68 SDna 95 DTan 69 DTSnaon 96 TDSxa 70 DSTDaox 97 DSTDSaoxxn 71 TSDTxaxn 98 DSTDoax 72 SDTxa 99 SDTnox 73 TDSTDaoxxn 100 SDTSoax 74 DTSDoax 101 DSTnox 75 TDSnox 102 DSx 76 SDTana 103 SDTSonox 77 SSTxDSxoxn 104 DSTDSonoxxn 78 TDSTxox 105 TDSxxn 79 TDSnoan 106 DTSax 80 TDna 107 TSDTSoaxxn 7 10 Color Vector Graphics HP GL 2 EN Table 7 1 Logical Operations ROP3 continued Boolean Boolean Input Value Function Input Value Function 108 SDTax 135 TDSaxn 109 TDSTDoaxxn 136 DSa 110 SDTSnoax 137 SDTSnaoxn 111 TDSxnan 138 DSTnoa 112 TDSana 139 DSTDxoxn 113 SSDxTDxaxn 140 SDTnoa 114 SDTSxox 141 SDTSxoxn 115 SDTnoan 142 SSDxTDxax 116 DSTDxox 143
232. y replicating each pixel four times in the horizontal direction and four times in the vertical direction Therefore a single pixel of a 150 dpi image is replicated by creating 15 new pixels A 75 dpi pixel is replicated by creating 63 new pixels The large scale replication of pixels for low resolution images is one of the main reasons for poor print quality first the image detail may be missing from the image because of the large pixel size and second a blocky pixelated effect occurs when the pixel is reproduced over and over again Various techniques have been devised to compensate for this pixelated effect For example rather than copy or replicate the pixel a bi linear or bi cubic interpolation algorithm could be used to smooth out the transitions by considering the surrounding pixels when making new pixels However this tends to blur edges or sharp transitions that are in the original image As a rule better print quality results from higher resolution images such as 150 or 300 dpi that use smaller pixels and cause less pixel replication Pixels represent specific spots within the picture In a black and white image where a pixel is either black or transparent white a single binary digit or bit can represent a pixel This has been the standard raster format for many years See Figure 6 2 for an example However in color images or grayscale images those with varying black dot sizes which yield a range of grays when viewed by the
233. y a copy of a palette is pushed onto the stack the original palette and ID remain in the palette store A palette popped from the stack goes into the palette store becomes the new active palette and assumes the ID of the previously active palette which is overwritten Only one palette at a time may be active Using Palettes Color LaserJet 5 5M DeskJet C 5 Management by ID allows applications to tag data have multiple raster configurations and have palettes for different color spaces all without reconfiguring the active palette For example one palette can be created for PCL text one for HP GL 2 primitives one for simple raster and one for 24 bit raster The application can then switch between palettes according to what is being sent to the printer Selecting a new active palette changes the PCL graphics state Besides color entries a palette also contains the graphics state at the time the bitmap representation of the palette colors was created This guarantees color reproduction integrity by insuring that the same color specification triplet always produces the same bitmap representation As described below the Select Palette Fc amp p S Palette Control Ec amp p C and Palette Control ID Fc amp p l commands implement the three basic operations of management by ID Selection of the active palette Deletion of palettes Copying of palettes Select Palette Command The Select Palette command selects a new active

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