Under color removal Under color removal In printing, under color removal (UCR) is a process of eliminating overlapping yellow, magenta, and cyan that would have added to a dark neutral (black) and replacing them with black ink only, called a "Full Black", during the color separation process. Under color removal is used in four-color (or more colors) printing. Black ink used to add details and darkness in shadowed areas is called a "Skeletal Black". With current ink technology, the total CMYK ink in the shadows refuses to stick after it reaches the dark shadows (usually above a 250% total CMYK coverage), and begins
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