Specifications

In theory, pure cyan, magenta, and yellow pigments should combine to absorb all color and produce
black. But because all printing inks contain impurities, these three inks actually produce a muddy
brown and must be combined with black ink to produce a true black. Combining these inks to
reproduce color is called four-color process printing.
Figure 5: In theory, mixing cyan, magenta and yellow yields perfect black; in practise the key color black has
to be added.
The Grayscale model
The Grayscale model uses shades of gray to represent objects. In this case, every pixel of a grayscale
image has a brightness value ranging from 0% (black) to 100% (white). The maximum number of
grays that most output devices can produce is 256.
11.3 Color gamuts and color spaces
The visible spectrum contains millions of colors, but color devices, such as scanners, monitors
and color printers can only (re)produce a subset of this spectrum. This “subset” is called a color
gamut. The gamut of a device defines the color space it can (re)produce. For example, a monitor
can display a wider range of colors than an offset press can print using CMYK colors, while some
of the CMYK colors cannot be accurately displayed on the monitor. Each device has a different
color gamut.
A - RGB color gamut
B - CMYK color gamut
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