1. A method of applying a tone scale function that is compressive, expansive or a combination of both to a digital image, the method comprising: a) decomposing the tone scale function into two or more composite functions that can be applied sequentially to the digital image; b) applying the first composite function to the digital image with a tone scale applicator to produce a tone scaled digital image; and c) applying the second composite function to the tone scaled digital image to produced an enhanced digital image.