1996 Volume 80 Issue 11 Pages 836-847
In order to evaluate the Helmholtz-Kohlrausch effect, heterochromatic lightness matches on 64 Munsell colors of 4/were made by 26 obsevers, and 88 Munsell colors of 6/by 24 observers. A bipartite field subtending a visual angle of 3°×3° with a surround was used. A surround of N4 was used for the test colors of 4/and of N6 for those of 6/. All heterochromatic lightness matches were made under fluorescent light (x =0.3126, y=0.3168; 4551x), and the viewing geometry was normal (0°) illumination with approximately 45°viewing. The individual data obtained by all observers and also their means are given in tabular form and the latter are also given in graphical form. The mean data were examined on the basis of the CIELAR color space, then an experimental formula was derived which gives the correlate for lightness of a surface color in terms of L*, C*, and h°. These results are compared with similar ones reported previously by other researchers. The results obtained in the present study indicate that the lightness of surface colors may be substantially predicted by a rather nonlinear equation of C* than linear one and there is a weak trend whereby the Helmholtz-Kohlrausch effect on surface colors having constant value of C* shows another shallow minimum at h°=300 which has never been reported.
