A COLORIMETRIC EXPLANATION OF THE HELMHOLTZ-KOHLRAUSCH EFFECT

The Helmholtz-Kohlrausch effect is related with the chromatic strength s of spectral colors suggested by R. M. Evans. An estimate of the chro matic strengths of spectral colors is given by using the color-matchin g functions and their combinations. The estimate of the chromatic stre ngth corresponds to ''chromaticness per unit luminance'' at each spect ral color. The derived chromatic-strength function is very similar to the Helmholtz-Kohlrausch effect and the zero-grayness-function by Evan s for spectral colors. (C) 1998 John Wiley & Sons, Inc.