Prediction of the Helmholtz-Kohlrausch effect (VCC method) using the Swedish NCS system

Abstract

The existence of the two methods of representation of the Helmholtz-Kohlrausch (H-K) effect was clarified in the previous studies by one of the authors. They are the Variable Chromatic Color (VCC) and the Variable Achromatic Color (VAC) methods. The effect by the VCC method is significantly larger than that by the VAC method, and the former is more effective in visual photometry than the latter. The authors already derived a prediction equation of the H-K effect by the VCC method using the CIELUV formula. In this work, a VCC prediction equation was directly derived from the colorimetric values of the Swedish Natural Color System (NCS). The new VCC equation is almost the same as the VCC equation previously reported. This again clearly suggests the existence of the two representation methods, and the theoretical method used for deriving the previous VCC equation is proved to be correct. © 1996 John Wiley & Sons, Inc.