Influence of color temperature on comfort and preference for LED indoor lighting

Correlated color temperature (CCT) is one of the most important lighting factors to influence the subjective perceptions, while there currently are few researches involving a wide range of CCT to study the comfort and preference within specific indoor scenarios. Therefore a psychophysical experiment with the method of forced choice was carried out in a light-emitting diode (LED) light booth with a panel of twelve observers to evaluate these estimations with different combinations of CCT and illuminance. The results show that Kruithof's rule is just a qualitative conclusion rather than an accurate expression about pleasing combination of CCT and illuminance, and that illuminance is not a significant factor to influence the estimations if it is limited within a moderate range. The detailed analysis indicates that CCT has significant impact on the subjective comfort and preference, and a set of models were proposed to predict these subjective perceptions for the scenarios of relaxing and working.