Contrast sensation: a linear function of stimulus contrast

The method of magnitude estimation was used to determine the relationship between stimulus contrast and contrast sensation for stimulus contrasts from 0.63% to 60% at spatial frequencies of 1, 2, 6.5, and 12 cycles per degree. The relationship between contrast sensation and stimulus contrast was found to be linear over the entire range of stimulus contrasts and spatial frequencies studied. A theoretical function for contrast sensation is proposed and the concept of a contrast sensation surface is introduced. Constant contrast sensation contours derived from this surface are shown to fit data from contrast matching experiments performed in other laboratories.