Evaluation of the Uniform Color Spaces Applied in the Specifications of Color Rendering Properties

Abstract

CIE-JIS method of color rendering specifications has a drawback, in that it cannot compare light sources with very different colors. The possibility is disscussed to remove the drawback by changing the uniform color space applied in the method.
Apparent three attributes of test colors (eight high level and eight medium saturation) under various kinds of light sources were estimated directly by two observers. Their perceived chroma diagrams are compared with psychometric chroma diagrams calculated in accordance with the CIELUV and CIELAB spaces.
The CIELAB space is much better than the CIELUV or CIELUW in simulating the apparent spacing of the test colors under various light sources. Effectiveness of several formulae for chromatic adaptation Correction was also tested. It is shown that only the nonlinear formula proposed by Nayatani et al. slightly improves the similarity of the CIELAB space to the percieved color space.
The authors are going to propose the adoption of the CIELAB space even in the color rendering specification at the CIE TC-3. 2 meeting.