Chromatic flicker fusion frequency as a function of chromaticity difference.

Abstract

The critical color fusion frequency (ccff) was measured for each of fifteen pairs of six colors at equal luminance. Measurements were made at five levels of luminance ranging from 9 to 67 trolands. Two subjects were used. The six colors were of high chromatic purity. Their dominant wavelengths covered the range of 445 mμ to 670 mμ in nearly equal steps. The relative chromatic separation between the members of each pair was estimated from Judd’s RUCS and from Wright’s data on the size of equally noticeable color steps in the CIE chromaticity diagram.The results show that log reciprocals of cff and ccff are nearly parallel and linear functions of luminance in log trolands. The product-moment correlation between persistence (1/ccff) and log chromatic separation on the RUCS was 0.84 and 0.91 when log chromatic separation was computed from Wright’s data.