A study of preferred colour rendering of light sources: Shop lighting

This paper provides recommendations for optimum LED light spectra in shop environments. The main aspects of the research were to elaborate the optimal LED spectral power distribution for the lighting of different colour textiles, fruits and vegetables, meat and bakery products. The spectrum was tailored towards different colour quality metrics such as the colour rendering index and the colour quality scale. Small scale investigations with eye-tracker studies were carried out by Osram Opto Semiconductors at the University of Regensburg and full scale experiments were conducted at the University of Pannonia during the project in order to determine which metric correlates best to the preference of the observers. Results of the psychophysical have been evaluated with the help of analytic hierarchy process and a modified Thurstone method. As a result of the investigation, optimal spectral power distributions for shop environment are described.