Colorimetric and Stochastic Assessment of the Visual Limit of Color Perception for Visual Colorimetric Analysis

Methods for evaluating the visual limit of color perception are proposed to create common rules for constructing color test scales in visual colorimetric assay using a probabilistic approach and instrumental measurements of the total color difference Delta E. Using a wealth of experimental data, we confirmed the previous idea that the minimum value of Delta E discernible by an average eye in 90% of cases may differ from the conventional criterion Delta E = 10. It has been shown that Delta E is not constant throughout the range corresponding to the visible spectral region and depends on the color tint of the scale. Using the dependence of the probability of color difference on the size of the scale step, a minimum step for each color tint is found. This makes possible the a priori selection of a step for constructing a calibration scale depending on its tint.