Threshold color differences compared to supra-threshold color differences

✍ Scribed by Rolf G. Kuehni

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 94 KB
• Volume: 25
• Category: Article
• ISSN: 0361-2317
• DOI: 10.1002/(sici)1520-6378(200006)25:3<226::aid-col11>3.0.co;2-v

✦ Synopsis

Threshold color difference ellipses, as represented by the MacAdam ellipses have been compared to unit contours implicit in the CIE94 color difference formula, found to represent small supra-threshold color differences well, both in the CIE chromaticity diagram as well as the a*, b* diagram. The results indicate that the two types of contours are significantly different. While threshold differences are well described by incremental changes in cone sensitivity supra-threshold differences are well-described by increments in the opponent color parameters a* and b*. A comparison of the hue angles in the a*, b* diagram of the MacAdam ellipses and the CIE94 contours for the same 25 colors indicates no correlation (correlation coefficient Ϫ0.1). The conclusion is that threshold and supra-threshold color difference perception operates at different levels in the color vision system.