Comparative study of visual comfort and neutral white perception on displays under varying ambient lighting conditions.

As modern mobile displays strive for accurate color reproduction across diverse ambient lighting conditions, they should equally account for visual comfort (VC). However, whether these two perceptual objectives are chromatically consistent remains unresolved. This study investigated the chromaticity discrepancy between visual comfort and neutral white (NW) perception on mobile displays through two psychophysical experiments conducted under six ambient lighting conditions, including a dark environment and five correlated color temperature (CCT) levels ranging from 3000 K to 8000 K at 500 lx. Seventeen observers performed neutral white matching by chromaticity adjustment and evaluated visual comfort during a reading task with various background colors. The perceptual boundaries of neutral white and visual comfort were characterized by fitting ellipses in the CIE 1976 u'v' diagram. Statistical analysis confirmed that visual comfort was primarily governed by display background chromaticity (CCT and Duv), with ambient CCT exerting no significant main effect. Neutral white centroids tracked chromatic adaptation, shifting from 3899 K to 8049 K with ambient CCT, whereas VC centroids remained stably anchored near 5400 K. Both ellipse types shared major axes parallel to the Planckian locus, indicating greater sensitivity to Duv than to CCT deviations. Exploiting this geometric relationship, a Comfort-Adapted White (CAW) framework was developed, yielding chromaticities (4879-6174 K) that significantly outperformed neutral-white stimuli in predicted VC scores. These findings provide empirically grounded chromaticity targets for adaptive white-point algorithms balancing chromatic fidelity and visual comfort in next-generation intelligent displays.