A technique for reducing the amount of magenta, cyan, and yellow in dark and neutral areas and replacing the amounts of CMY with black.
The technique works in the following way: colored ink is used up to a certain value, after which black is added in order to improve the dark areas of an image, so that total ink coverage (TIC) is not exceeded.
The image reproduction will appear normal but will use less ink, the shadows will have more detail, and trapping will be improved.
Cyan, magenta and yellow are removed as far as they are identical and replaced with the equivalent amount of black.
The depth of colors is thus improved and the total amount of printing ink reduced.