ANOMALIES IN ADDITIVE COLOR MATCHES

W. A. Thornton [W. A. Thornton, Toward a more accurate and extensible colorimetry, Parts I-III, Color Res. Appl. 17, 79-122, 162-186, 240-26 1 (1992).] reported significant discrepancies in Maxwell colour matche s when wing different sets of primary lights. His experiments were per formed by a small, mainly older group of observers. The aim of this in vestigation was to test these findings over wider age ranges. We match ed a broadband white Eight of constant luminance with two sets of thre e monochromatic primaries. These sets were similar to Thornton's AP se t (497, 579, and 653 nm) and Thornton's PC set (452, 533, and 607 nm). Thirty-two observers performed the tests with 10 degrees fields. The chromaticities of the matches made with the AP set had a large varianc e and were centered around the chromaticity of the reference white. Th e chromaticities of the PC-primary matches were clustered closely toge ther and were centered at a point significantly different from the chr omaticity of the reference white. The magnitudes, but not the directio ns, of the dispersions of the matching chromaticities were consistent with age related changes in the spectral transmission of the lens. (C) 1995 John Wiley and Sons, Inc.