Warm-Cool Emotions of LED Lightings around 5,000K

Abstract

In this study, warm-cool feelings of near-white lightings were investigated after the subjects’ eyes being adapted to 5,000K. The psychophysical experiment was carried out in a dark room using 5 channels LED lighting booth. In the experiment, total of 48 test lightings around 5,000K were generated using the booth. Total of 20 subjects evaluated warm-cool feelings of each test lighting. The results showed that lower CCT tended to have ‘Warm’ feeling, while higher CCT tended to arouse ‘Cool’ feeling. When CIECAM02 H is in the range of 0-100 and 380-400, ‘Warm’ feeling was strongly evoked and when H is in the range of 250-300, ‘Cool’ feeling was strongly aroused. Also, when test lightings have same hue, the one having higher chroma aroused stronger feeling on either ‘Warm’ or ‘Cool’. Emotion model test results showed Koo’s model, which is based on lighting colors, showed better performance than the model developed based on color patches.