Comparison of Color Systems with Respect to Uniform Visual Spacing

The present study is a comparison of ten systems of color specification, for a restricted chromatic area around the neutral at a single luminance level, with respect to their relative adherence to uniform visual spacing. A sample of 20 visually equi-spaced (Munsell renotation) chromaticities at the same luminance were used. Chromatic coordinates for these colors were expressed in each of the ten systems and plotted in their respective chromaticity diagrams. Then all data were reduced to the same scale, after which radial saturation distances and hue angles were compared to those in the Munsell renotation criterion. Rank orders of departure from the criterion were determined for hue and saturation separately. Results show that all the 10 systems include visually significant departures from a uniform color space. These results may be generalized beyond the present sample because, if other more saturated colors were added to the present sample, there would be even greater departures from uniform spacing. The use of any particular system in any particular instance depends on circumstances, the time and personnel available, the number of points to be transformed, and the accuracy with which it is desired to illustrate visual relationships. Where the accurate expression of visual relationships is of prime importance, Munsell renotation is recommended because it was designed specifically to show equal visual intervals.