The von Kries coefficient law of chromatic adaptation—that there is linear proportionality between stimulus and response for each of three types of visual receptor—results in systematic discrepancies between prediction and experiment. A hypothesis that the responses of the receptors are nonlinear was fairly successful when applied to three sets of experimental data obtained independently by quite different methods. Analysis of additional data confirms the earlier conclusions that (1) discrepancies of predictions of corresponding colors by the linear hypothesis are significantly large and systematic; (2) the discrepancies are less systematic and are significantly reduced by the nonlinear hypothesis; (3) the most successful forms of the mathematical relations expressing the nonlinearities are systematically dependent on the chromaticities of the adaptations. These forms are substantially the same as those for the three sets of experimental data previously studied.
DAVID L. MACADAM, "Chromatic Adaptation. II. Nonlinear Hypothesis," J. Opt. Soc. Am. 53, 1441-1445 (1963)