HP QMS 1660 - Manual (Page 136)

HP-GL Color
Encoding
QMS 1660 Print System Reference 5-36
Since your QMS 1660 Print System is a monochrome (black and
white) printer, the pen colors are converted to shades of gray. The
default color mappings for the 8 pens are as follows:
» Note: The default color for both pen 1 and pen 2 is black. However,
the pen width for these two pens is different. Pen 1 is 0.7 mm and pen
2 is 0.3 mm.
The printer maps each pen to its assigned color, then converts the
color to a grayscale using the National Television System Committee
(NTSC) standard equation for encoding color. This equation converts
a given set of CMYK values to grayscale. For the 8 pen colors
assigned to pens 1 - 8, the printer uses the designated grayscale; for
any other pen color, the printer uses the following equation:
[(C*0.3) + (M*0.59) + (Y*0.11) + K]
÷
255
» Note: This equation assumes that each grayscale is a byte value that
ranges from 0 to 255 (100%). If the sum of the left-side (calculation in
brackets) of the NTSC equation is greater than 255, then the sum is
set equal to 255.
Pen Pen Color Level of Gray
1
2
3
4
5
6
7
8
Black
Black
Red
Green
Blue
Violet
Orange
Brown
100%
100%
70%
41%
89%
59%
25.8%
50%