Gray Component Replacement
A technique used in the color separation process that replaces the neutral gray portion in cyan, magenta, and yellow with black. Instead of the cyan, magenta and yellow to producing these grays, they are produced with the black ink.
GCR will deepens the shadow areas of an image that lacks depth and reduces the amount of ink required which speeds up drying time. Colors are easier to maintain throughout the run and may produce a more pleasing printed product.