Are we able to distinguish color attributes?

The perception and understanding of the three color attributes have been an alyzed from two experiments using pairs of Munsell sample, where only one o f the three color attributes were changed/unchanged (Experiment I/II) at a time. In each experiment, 36 pairs with color differences of 3 different si zes (average values of 15.8 and 21.7 CIELAB units for Experiments I and II, respectively) were assessed under standardized conditions by 40 normal obs ervers, 20 of them with previous knowledge and experience in colorimetry. A t a 95% confidence level, the results from the two experiment were not sign ificantly different, indicating that color attributes were not easily disti nguished: for example, for experienced observers, the percentage of correct answers for identifying the color attribute responsible for a color differ ence was only 72.4%, the random probability being 33.3%. There were no sign ificant differences between the results found by men and women. The worst d istinguished attribute was Chroma, that is, the least frequent confusion wa s between Hue and Value or vice versa. Value differences were more easily d etected for achromatic than for chromatic pairs, both for experienced and i nexperienced observers. With respect to the size of the color differences, we observed that large hue differences were more easily identifiable than s maller ones, and a constant Hue was more identifiable when the entire color difference was small. (C) John Wiley & Sons, Inc.