Process color is a common shortened form of the term “four-color printing process.” Process color (and similar terms) refers both to a method of reproducing colored images on printing presses and to the specific ink colors used. Other ways of referring to this printing process include “four color,” “CMYK,” and “full color.”
The four-color printing process is based on mixing pigments of the four following colors in order to make other colors: cyan, magenta, and yellow, plus black. Using black ink provides shadow detail and reduces the amount of the primary colors needed to print dark hues.
Full-color printing relies on color mixing and human color perception. It is the dominant method of printing that is capable of reproducing a full range of color, required for reproducing color photographs in newspapers, books and magazines.