Extending CIECAM02 and CAM16 for the Helmholtz–Kohlrausch effect

Abstract Increasing the purity of a visual stimulus increases its brightness, even if the stimulus luminance is held constant. This perceptual phenomenon is known as the Helmholtz–Kohlrausch (H–K) Effect. This paper reviews published experimental data and models of the effect. Using past experimental data, we derive a modification of the CIECAM02 and CAM16 color appearance models to account for the H–K effect and compare the proposed model to other models. Finally, we discuss the need for further experimental data on the H–K effect to refine the proposed model.