GCR Gray Component Replacement is a variant of the color build-up in printing. GCR and UCR (Under Color Removal) are opposite processes. Figuratively speaking,this means: While UCR creates color image, and then replaces the deep dark values by black, GCR creates a black and white image, and then colorizes it, as this was done in the past, for example, with colored engravings. A lower ink consumption results in GCR as well as in UCR in faster drying, less ink consumption and also in a better reproduction of images.