Under color addition
(Redirected from Under Colour Addition)
In under color addition (UCA) the same results as under color removal can be obtained, but from a different starting position.
In four-color printing, the under color removal (also short UCR) is a technique to convert from the CMY color space into the CMYK color space. Grey areas composed of all three colors—cyan, magenta and yellow—are converted into only the fourth black channel.
In under color addition small portions of the three colors are added to the uncolored areas.