CMYK color model leaves magenta, and white light minus blue leaves yellow. In additive color models, such as RGB, white is the "additive" combination of all primary colored lights, while black is the absence of light. In the CMYK model, it is the opposite: white is the natural color of the paper or other background, while black results from a full combination of colored inks. To save cost on ink, and to produce deeper black tones, unsaturated and dark colors are produced by using black ink instead of the combination of cyan, magenta, and yellow. With CMYK printing, "halftoning" (also called "screening") allows
Color printing are variously used in printing, the result should be a reasonable reproduction of the original, but in practice this is not the case. Due to limitations in the inks, the darker colors are dirty and muddied. To resolve this, a black separation is also created, which improves the shadow and contrast of the image. Numerous techniques exist to derive this black separation from the original image; these include grey component replacement, under color removal, and under color addition. This printing technique is referred to as CMYK (the "K" stands for "key", a traditional word for the black printing plate). Today's