Threshold data in CIE 1976 UCS colourspace. The experiment was carefully controlled for illumination and employed dark, daylight D65, and cool-white fluorescent TL84 lighting. The stimuli were carefully reconstructed from multispectral measurements of skin textures. Just-noticeable differences (JNDs) were measured using a 4-alternative forced-choice task with multiple repetitions.
Reuslts show that human colour vision adapts to higher-order statistics of the colour distribution in natural textures, and is tuned for optimal performance under natural/naturalistic daylight. A link to the data will be made available shortly.
Reference : Chauhan, T., Xiao, K., & Wuerger, S. (2019). Chromatic and luminance sensitivity for skin and skinlike textures. Journal of Vision, 19(1), 13–13. [doi]