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 magenta a single wavelength. Humans, being trichromats, can only see as far as 380 nanometers into the spectrum, i.e., as far as violet. The hue magenta is the complement of green: magenta pigments absorb green light, thus magenta and green are opposite colors. Before "printer's magenta" was invented in the 1890s for CMYK printing, and "electric magenta" was invented in the 1980s for computer displays, these two artificially engineered colors were preceded by the color displayed at right, which is the color originally called "magenta" made from coal tar dyes in the year 1859. Besides being called original magenta, magenta dye