Xerox DocuColor 2060 - Manual (Page 37)

A B O U T C O L O R P R I N T I N G
D O C U C O L O R 2 0 6 0 / 2 0 4 5 O P E R A T O R M A N U A L
A
B
OU
T
C
OLO
R
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IN
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G
1–9
Adding and Replacing Gray to Improve Color
There are limitations to achieving the exact colors when converting
from RGB (for video display) to CMY (for print). For example, CMY
pigments aren’t capable of producing consistent black or gray tones.
In cases in which the three ink or toner colors overlap heavily,
software applications automatically vary the percentages of cyan,
magenta, and yellow to enhance image quality and improve
printability. This technique is known as undercolor removal, or UCR, in
which black ink is used to replace cyan, magenta, and yellow ink in
neutral areas only (that is, areas with equal amounts of cyan,
magenta, and yellow). This uses less ink and provides greater depth in
shadows. UCR is generally used for newsprint and uncoated stock
Another form of undercolor removal is called Gray Component
Replacement (GCR). To compensate for the neutral or grey tones
created during the conversion of RGB to CMYK, black ink replaces
portions of cyan, magenta, and yellow ink in colored areas, as well as
in neutral areas. GCR separations tend to reproduce dark, saturated
colors somewhat better than UCR separations do, and they maintain
gray balance better in print.
UCR UCR
UCR
No GCR
Light GCR
Medium GCR
Maximum GCR