USER EVALUATION OF EIGHT LED LIGHT SOURCES WITH DIFFERENT SPECIAL COLOUR RENDERING INDICES R9

摘要

In this study we evaluated the influence of the special colour rendering index R_9 on subjective red colour perception and Caucasian skin appearance among untrained test subjects. The light sources tested are commercially available LED based light sources with similar correlated colour temperature and general colour rendering index, but with varying R_9. It was found that the test subjects in general are more positive towards light sources with higher R_9. The shift from a majority of negative responses to a majority of positive responses is found to occur at R_9 values of ～20.