Preference among light sources with different Duv but similar colour rendition: A pilot study

Recent studies have suggested that light sources with chromaticities slightly below the blackbody locus are preferred by human observers. The preferred light settings identified in these studies, however, had high values of colour fidelity and colour gamut. It has been speculated that the preference was caused by good colour rendition, rather than chromaticity. This article reports a pilot study in which the spectral power distributions of the light settings were carefully designed using a genetic algorithm. Twenty-three observers evaluated pairs of light settings at 3000 K and 6500 K with different chromaticities, in terms of D-uv, but similar colour rendition as characterized using the IES TM-30-15 R-f, R-g, and Color Vector Graphic. It was found that the light settings with D-uv of -0.02 and -0.03 were most preferred among the 3000 K settings; while the settings with D-uv of 0 and -0.01 were most preferred among the 6500 K settings. Further studies regarding how chromaticity alone affects preference under different viewing conditions and adaptation conditions will be valuable to better understand human preference for light stimuli.