Fixed range scales applied to the evaluation of color: Comparative analysis between the Munsell System and the Natural Color System

In this article, we discuss the effect of anchoring on the estimation of chromatic variables, which occurs when fixed range scales are used in psychophysical measuring. In order to do this, we compare the Munsell System and the Natural Color System (NCS), and an alternative system that employs a scale of grays as a yardstick against which to measure value and saturation. During experimentation, observers evaluated 60 matte surface color samples, following the methodology proposed by each system, but without using their respective color atlases. The data obtained reveal results that are compatible with the measurements based on the Munsell System and the NCS. By applying the gray-scale method, the value measurements improved, whereas the saturation measurements were overestimated in samples with low reflectance. In all the cases, hue shifts were observed and thought to be attributable to the variation in luminance revealed by the samples. Judging by the similarity of the results obtained, it can be assumed that when fixed range scales are used, measurements will be anchored to their extremes, equaling every measurement made with them. (C) 2003 Wiley Periodicals.