There are two ways of printing colors: process and spot.

Spot color printing is when a select set of specific colors is chosen which match those used in the image to be printed. Typically, spot colors are used for graphic art with only a few solid colors, such as logos and brochures. Because most printers charge more for each ink color used, spot printing with one, two, or three colors is often prefered. Spot printed images often contain only solid colors with no halftoning.

Process printing (also refered to simply as four-color printing) is usually synonymous with CMYK. Process is so named because any image can be processed into cyan, magenta, yellow, and black plates easily.

Process printing, though it usually uses more inks, does not always produce the best results. For instance, a black and white photo will gain nothing from the use of cyan, magenta, and yellow. A better result can be had with gray and black spot inks for less money.

It is also possible to print using more than four colors. Likewise, it's possible to print both spot and process at once. Some cereal boxes, for example, are printed with 5 or 6 inks: CMYK, plus the exact colors used in the logo or in the background. This permits a CMYK photo of the product and a crisp, solid colored logo without any halftoning.