Color printers use the subtractive color model and use cyan, magenta, and yellow inks. To compensate for the impure nature of most printing inks, a fourth color, black is also used since the black obtained by combining cyan, magenta, and yellow inks is often a murky dark green rather than a deep, rich black. For this and other reasons, commercial color printing presses use a 4-color process to reproduce color images in magazines.
A color created by mixing equal amounts of two primary colors is called a second¬ary. In the additive color system, the primary colors are: