QMS 1060, User Manual

Page: 166 / 311

HP-GL Color
Encoding
QMS 1060 Print System Reference 5-36
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.
Example
Any color can be reproduced by using some combination of CMYK. If
you have defined the following CMYK values for the color brown in
your application, the NTSC equation that follows shows you how the
percentage of grayscale for the color is derived.
CMYK Value
C (96)
M (128)
Y (224)
K (0)
[(96*0.3) + (128*0.59) + (224*0.11) + 0]
÷
255 =
[(28.80) + (75.52) + (24.64) + 0]
÷
255 = 50%
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