Warm–Cool Judgments in Complementary Color Mixing

This study aims to investigate the structure of warm–cool judgments in complementary color continua and to analyze the absolute and relative characteristics of the warm–cool judgments of color based on RYB mixing ratios. To this end, 33 stimuli were generated along three complementary color continua (R–G, O–B, Y–P) by systematically mixing RYB primary colors with their complementary colors at 10% intervals. Based on the color continua and the neutral points identified in An & Park (2026), both absolute warm–cool judgments (single-stimulus presentation) and relative warm–cool judgments (paired comparison) across between-hue and within-hue conditions were examined. The experiment was conducted as an online survey with 43 adults aged 20–50 who self-reported normal color vision. The results showed that, in relative warm–cool judgments (between-hue), the warm–cool judgment structure centered on the O–B axis, as reported in previous studies, was also observed in the complementary color continua examined in this study, with orange functioning as the warm reference and blue as the cool reference. In absolute warm–cool judgments, chromatic neutral stimuli perceived as brown due to complementary mixing, accompanied by reduced lightness and chroma, tended to be evaluated as warm within the experimental conditions of this study. Furthermore, in relative warm–cool judgments (within-hue), stimuli closer to the neutral point and perceived as brown tended to be judged warmer than their more saturated counterparts. These findings suggest that, within the RYB-based complementary color continua examined in this study, specific brownish chromatic neutral stimuli generated through complementary color mixing may show a relatively warm tendency in warm–cool judgments. In conclusion, within the R–G, O–B, and Y–P complementary color continua examined in this study, warm–cool judgments based on RYB mixing ratios were found to be consistent with the tendency structure reported in previous studies, providing a basis for understanding the warm–cool characteristics of chromatic neutrals formed through RYB-based complementary color mixing.