1. A color management method using an input device appearance transform and an output device appearance transform together with a customizable gamut mapping algorithm so as to transform image data from an input colorant space to an output colorant space during a color management session, said method comprising the steps of: customizing the gamut mapping algorithm based at least in part on the color management session in question; and applying the customized gamut mapping algorithm to either the input device appearance transform or the output device appearance transform, or both, so as to result in a composited transform that incorporates a customized gamut mapping.