EVALUATION OF COLOR-DISCRIMINATION ELLIPSOIDS IN 2-COLOR SPACES

We obtained the color-differential thresholds for 20 stimuli and 3 obs ervers within 2 color-representation spaces. First, in the CIE-1931 co lor space we compare the results of our experiments, which followed ch romatic-discrimination criteria, with those obtained by other authors that followed color-matching criteria. Second, the representation of o ur data in the cone-excitation space shows that all the discrimination ellipses are nearly oriented along the S-cone-variation axis. In our experiments the variations in the threshold of each color channel acco rding to its level of excitation are similar to those found by other a uthors using different experimental conditions and methods, but certai n discrepancies appear when the influence that one color channel may e xert on the other is analyzed. The characteristics of luminance discri mination are shown to be independent of the chromaticity of the stimul i.