US Patent 7567705 Protecting colors from clipping

Methods and apparatus, including computer program products, for protecting colors from being clipped during color adjustment. A first set of colors is identified in a source color space, and a first color mapping is specified to associate colors in the source color space with mapped colors. The first set of colors and the first color mapping are used to construct a third color mapping that can be represented as a concatenation of an injective second color mapping with the first color mapping. The third color mapping is constructed such that each color in the first set of colors is associated with a mapped color inside a destination color space.