Gray scale and achromatic color difference

Gray scale is a preferred method for information display, yet existing techniques for constructing a gray scale rely on mathematical formulas that are ambiguous and inconsistent with known phenomena of suprathreshold achromatic perception. To improve this situation, problems are discussed, literature on suprathreshold achromatic perception is reviewed, existing gray-scale formulas are compared with human-performance data, and a new approach is examined. The new approach takes into account the luminances of the surround, the targets, and the distractors that are to be rendered in a gray scale. It is theory based, is consistent with known phenomena of suprathreshold achromatic perception, and fits human-performance data at least as well as any other formula.