CIELab Color Space and Perceptual Brightness Issues: The Red Brightness Discrepancy
2025-01-17
This article explores the limitations of the CIELab color space and its modern variants (CIECAM02 and Oklab) in predicting perceived brightness. While designed for perceptual uniformity, they don't perfectly predict human color perception, especially with highly saturated colors like red. This deviation, known as the Helmholtz-Kohlrausch effect, makes reds appear darker in CIELab than they actually are. The author proposes a new method based on 'Predicted Equivalent Achromatic Lightness' (L_EAL) to address this, highlighting its superior accuracy in applications like image desaturation.