The Weber fraction and asymmetries in luminance thresholds

Abstract

Presented in this article is a method for the determination of the Weber fraction by analyzing data obtained from color-matching experiments. The method is based on a rigorous analysis of the probability density function derived from discrimination judgments made in the xyY space. Analysis shows the thresholds for luminance increments and decrements are shown to be different and asymmetric and the Weber fraction to depend on the target's level of luminance and chromaticity.