CMYK (for cyan, magenta, yellow and key (black) [1] and often referred to as colors or four colors) is a subtractive color model used in color printing, also used to describe the process of printing itself. Although it varies by print house, press, press and printing, the ink is generally applied in the order of the abbreviation [2].

The CMYK model by partially or entirely masking certain colors on the typically white background (that is, in absorbing wavelengths of light). Such a model is called subtractive because inks "subtract" brightness from white.