1. A method for transforming colors between source and destination color imaging systems, the method comprising: using forward transformation profiles that characterize the source and destination color imaging systems to generate respective sets of device-independent color values for the source and destination color imaging systems; calculating color conversions for different combinations of source and destination color imaging systems by iteratively reducing differences between the respective sets of device-independent color values; constructing color maps describing relationships between the different combinations of source and destination color imaging systems using the color conversions and user preferences; storing the color maps; and when a user requests a transformation for a selected combination of the source and destination color imaging systems and selected user preferences: determining whether one of the color maps corresponds to the selected combination and the selected user preferences, if so, retrieving the corresponding color map, and if not, constructing a new color map for the selected combination and selected user preferences.