To produce a color image, many reproduction systems take advantage of the fact that there
are small sets of colors that, when mixed in the correct proportions, can produce any of a
very wide range of other colors. For example, combinations of red, green, and blue inks
13 Color Separation
358 OEM Manual Harlequin MultiRIP v10.0r0 May 2013
(commonly known as RGB), or cyan, magenta, and yellow inks (CMY), can between them
produce thousands of different hues.
Color printing more commonly uses CMY colors, with the addition of a black ink to account
for imperfections in the printing process. This manual uses the term CMYK for the system of
color representation using these four inks (Cyan, Magenta, Yellow, and blacK). These inks are
the commonly used process colors. There are several other terms in common use, some terms
using B for Black or referring to the order of printing each ink by reordering the letters:
YMCK, YMCB, and KCMY are typical.
Black ink is used for several practical, economic, and quality reasons:
• Black appears very often: for example, in text.
• Black ink is cheaper than colored inks.
• Mixing CMY inks produces an impure black, probably tinged with brown, and can
result in objectionable colored fringes on small objects such as characters in body text.
Additionally, one application of black ink replaces three applications of colored inks so
drying time can be reduced.
• Black can be used to extend the range of colors and tints available from mixing CMY
inks.
There are ways to improve reproduction quality or economy beyond the levels possible with
CMYK process inks. There are two general approaches: to vary the number of process inks
(HiFi or N‐color printing), or to add spot colors. Each approach has its own advantages
đang được dịch, vui lòng đợi..