The Helmholtz-Kohlrausch effect on display-based light colors and simulated substrate colors

The Helmholtz-Kohlrausch (H-K) effect is investigated in relation to light colors of every hue, including those typical of print substrate colors that might be simulated on a graphic arts display. A method of adjustment is used in conjunction with a soft-proof setup, in which an achromatic stimulus is adjusted until it has the same lightness appearance as a set of test colors. Higher chroma colors are found to appear lighter than their metric $L^{*}$ would indicate. The H-K effect is found to be quite strong in bluish colors, but negligible in yellowish colors, consistent with several previous studies. However, qualitative analysis reveals a peak H-K effect in red-magenta hues. We propose a modification to Fairchild and Pirrotta's existing H-K lightness appearance function¹ which addresses the peak in red hues, and which may prove beneficial in hue-dependent applications.