Abstract: Apparatus and method are disclosed for modifying the brightness levels of three color digital images to make them compatible with an output display device which has a fewer number of available brightness levels for each color than the color digital images. Color histograms are produced for each color digital image. Each histogram is used for producing a transform function which operates on one of the color digital images to perform the following modification: a predetermined number of the digital pixels having the darkest brightness levels are assigned to the darkest brightness level of the output display device and a predetermined number of the digital pixels having the brightest brightness levels are assigned to the brightest level of the output device. The remaining pixels of the color digital image are assigned to their corresponding remaining output levels of the display device.