Perceived Neutrality of White Stimuli on an LCD Using the Paired Comparison Method

This study investigates perceived neutrality in white light across a range of correlated color temperature (CCT) and Duv values. Two psychophysical experiments were conducted in a dark room using an LCD screen that displayed “white” patches of equal luminance (70 cd/m 2 ) against a black background. In both experiments, 30 observers with normal color vision performed paired comparisons to select the patch that appeared “less tinted” Experiment 1 examined how Duv affected perceived neutrality using 25 white stimuli varying in CCT (3000K, 4000K, 5000K, 6500K, and 9500K) and Duv (0.010, 0.005, 0, −0.005 and −0.010). The results show that the Duv value for the neutral white shifts with CCT: negative below 4000K and increasingly positive above, reaching 0.003 at CCTs higher than 6500K. Experiment 2 assessed the effect of CCT on perceived neutrality across a different CCT range (5000K, 5700K, 6500K, 7700K and 9500K) while maintaining the same set of 5 Duv levels used in Experiment 1. Results indicate the chromaticity associated with the maximum neutrality lies between 7000K and 8000K. The findings of both experiments suggest that the most neutral white corresponds to CIE Illuminant D75, which is specified at 7504K with a Duv of 0.0031. Based on these results, a predictive model of perceived neutrality was developed, defined as a neutral white locus extending from 3000K to 10 000K.