Subtractive colorimetry achieves metameric matching by removing portions of the spectrum from white light. The subtractive counterparts to the additive color primaries are those which when removed from white leave the red, green, and blue accordingly cyan, magenta, and yellow. Combinations of these subtractive colors in various add mixtures provide metameric matches to many colors. Subtractive color principles are employed in all hard-copy color images and in light-valve systems such as color transparencies, LCD panel display, motion-picture films, etc.