HP PCL/PJL reference (PCL 5 Color) - Technical Reference Manual

B-20 Using Color Modes (Color LaserJet, 5, 5M, DeskJet) EN
FLOATING POINT FORMAT
The following format is used for device-independent color floating
point specifications:
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 spaces 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.
31 30 23 22 0
Sign Exponent Fractional Portion
Byte 15 (msb) 8 7 (lsb) 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 (lsw) 9
10 y Chromaticity for red primary (msw) 11
12 y Chromaticity for red primary (lsw) 13
14 x Chromaticity for green primary (msw) 15
16 x Chromaticity for green primary (lsw) 17
18 y Chromaticity for green primary (msw) 19
20 y Chromaticity for green primary (lsw) 21