Hue and warm-cool feeling as the visual resemblance criteria for iso-CCT judgment

Abstract

The hue perception and ‘warm-cool’ feelings were investigated, in response to various lighting settings, following the adaptation to either 3500K or 5000K to compare which one—between conventional iso-Correlated Color Temperature (CCT) and a new one based on CIE u'v′ color space—is more compatible with the visual perception. Twenty participants evaluated hue and warm-cool feelings for 48 test lighting settings, by observing an empty gray booth. The results showed that yellow-blue and ‘warm-cool’ feelings are closely located around the Planckian locus, while red-green roughly follows the line orthogonal to the Planckian locus in CIE u'v′ color space, at both 3500 K and 5000 K settings. This suggests that u'v′ color space correlates better with human perception.