Changes to PCL 5 Color Commands

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Changes to PCL 5 Color Commands

The focus of the printer’s color support is on WYSIWYG color usage
and a simplified usage model. A number of PCL 5 color commands
introduced in the HP Color LaserJet and supported in the Color
LaserJet 5 printer have been made obsolete as a direct result of using
Standard RGB color to achieve WYSIWYG color. Furthermore,
several commands have been modified to match the predicted use of
the HP Color LaserJet 4500 printer.

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Printer-Specific Differences 2-115

PCL 5 Commands No Longer Supported or Greatly
Simplified

Driver Function Configuration — This command had five

options for the HP Color LaserJet and Color LaserJet 5
printers: Lightness, Saturation, Scaling Algorithm, Select Color
Treatment, and Download Color Map. Select Color Treatment
is the only option supported on the HP Color LaserJet 4500
printer. The range of values has been reduced to two choices:
Vivid (2) (no color adjustment) and Screen Match (6).

Raster Destination and Raster Width — four decimal places

of precision were added to avoid rounding errors when
converting to pixels.

Picture Frame Scaling Command — four decimal places of

precision were added to avoid rounding errors.

Configure Image Data — This command had two major

forms, the short form which selected default values for each of
the color spaces specified, and the long form which allowed a
complete specification of the parameters that characterize the
color spaces. The long form of the command is not supported
on this printer since the Luminance-Chrominance, CIE L*a*b*,
and Colorimetric RGB (cRGB) color spaces are not supported.
The supported color spaces are Standard RGB (sRGB),
Device RGB, and Device CMY. The sRGB color space is
selected using the same value as cRGB to enable files printed
with the Color LaserJet and Color LaserJet 5 drivers to take
advantage of the Color LaserJet 4500's use of sRGB for
WYSIWYG color. Furthermore, the specification of white and
black points for the Device RGB and CMY color spaces, and
the HP-GL/2 Color Range command, is not supported.

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2-116 Printer-Specific Differences

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Render Algorithms — There are no new algorithms for this

command that had twenty different algorithms, of which almost
half of them were monochrome equivalents of color
algorithms. The following table lists the algorithms that are
supported:

The monochrome algorithms are no longer supported since
there are no applications which allow the user to specify that a
color image should sometimes be printed in color and other
times in black and white. The remainder of the algorithms are
not supported as they are not needed for quality WYSIWYG
color printing.

Download Dither Matrix — Not supported

Color Lookup Tables — Not supported since it does not

support WYSIWYG color.

Gamma Correction — Not supported since it does not

support WYSIWYG color.

Viewing Illuminant — Not supported since it does not support

WYSIWYG color.

Monochrome Print Mode — This command is only supported

at the beginning of a job, since user applications only support
the choice of monochrome printing of color documents for an
entire document.

Algorithm

Command

Contone Best (High LPI)

?

*t0J

Device Best (Best)

?

*t3J

Smooth Contone (High LPI)

?

*t15J

Basic Contone (Low LPI)

?

*t18J

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Printer-Specific Differences 2-117