The Study of Subjective Evaluations of Colour Rendering of White Light Sources with Variable Chromaticity

The effect of spectral composition of white light sources with variable chromaticity on objective and subjective evaluations of their colour rendering was studied. The dependences of the colour rendering indices on colour temperature were obtained for four light sources: a tungsten halogen lamp, white light emitting diodes with adjustable correlated colour temperature, fluorescent lamps of three colours, and three-colour light emitting diodes. The dependences of general colour rendering index (CRI) Ra and Smet’s memory colour rendering index (MCRI) Rm on the distance uv between a point corresponding to the studied radiation and the blackbody line in the 1960 CIE system (u, v) at constant correlated colour temperature 6500 K were also studied for an installation with three-colour light emitting diodes. The conditions, in which these indices reach their maximum values, were identified.