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
Natural Color System more colors (184 light colors and 16 in the blue-green space) were added, adding to the current 1950 colors in the NCS 1950 standard colors. Colors that have a representation in the NCS 1950 samples are denoted with a leading capital "S", for example NCS S 1070-Y10R (a chromatic, slightly reddish yellow). The most important difference between NCS and most other color systems resides in their starting points. The aim of NCS is to define colors from their visual appearance, as they are experienced by human consciousness. Other color models, such as CMYK and RGB, are based on an understanding