The variation in width and position of mach bands as a function of luminance.

Abstract

When the luminance of a stimulus field is graded along one dimension in such a way as to show at some point a sufficiently sharp but continuous decrease in luminance, a bright band is seen in the vicinity of this decrease. Detns. of width of the apparent bright band were made at 5 values for the log. of max. luminance of the field, over a range of approx. 3.5 log millilamberts, for each of two gradients varying in rate of decrease of luminance within the upper half of the field. When the rate of decrease of log luminance is held constant, and the log of max. luminance is increased, width of the apparent band decreases according to a negatively accelerated function. When the rate of decrease of log luminance is increased and the log max. luminance is held constant, width of the apparent band decreases. The findings are discussed in relation to theories of retinal interaction.