The Effect of Chromatic Adaptation on Color Rendering

Abstract

Present-day calculations of color-rendering index are based on color differences determined using the test light source and a standard illuminant. Chromatic adaptation is corrected by the von Kries transformation and the color differences are calculated in the CIE 1964 uniform color space. The present article discusses the possibility of introducing either the CIE 1976 CIELUV or CIELAB color space for calculating the color differences, and investigates how different forms of chromatic-adaptation corrections influence the color differences. It is concluded that a change from the present system to a CIELUV color-space calculation would not affect the color-rendering indices considerably; changing, however, to other color spaces or to a single reference illuminant with a better chromatic-adaptation formula (Bartleson-type chromatic-adaptation correction) would change the color-rendering order of some light sources. In the present article some critical samples and light sources are pointed out, where a comparison between the different types of calculations is possible.