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
Shades of blue system are the three colors of light chosen such as to provide the maximum gamut of colors that are capable of being represented on a computer or television set. This color is also called color wheel blue. It is at precisely 240 degrees on the HSV color wheel, also known as the . It is a spectral color which lies at, or near, the short-wave (violet) end of the traditional "blue" and possibly was classified as "indigo" by Newton. Its complementary color is yellow. The color defined as "blue" in the CMYK color system used in printing, also known as