Computer-Produced Grey Scales

Abstract

Pictorial output from computers is usually binary—that is, microscopically black or white at a point owing to the physical processes involved. A number of techniques have been developed in the past to derive subjective grey values using binary-output devices. Several new extensions of these techniques are reported here. The basic procedure is to quantize space into cells which are filled with different sizes and shapes of black areas on a white background (or vice versa). We include several examples which result from judicious selection of patterns or from rules which divide cells into particular classes of black and white regions. Some of the results raise intriguing questions about the physiology and psychology of vision.