Colour rendering of indoor lighting with CIE illuminants and white LEDs for normal and colour deficient observers

The goal of this work was to evaluate the colour rendering of indoor lighting with CIE illuminants and white LEDs by estimating the chromatic diversity produced for normal and colour deficient observers. Reflectance spectra of a collection of scenes made of objects typically found indoors were obtained with hyperspectral imaging. Chromatic diversity was computed for 55 CIE illuminants and five LED light sources by estimating the number of different colours perceived in the scenes analysed. A considerable variation in chromatic diversity was found across illuminants, with the best producing about 50% more colours than the worst. For normal observers, the best illuminant was CIE FL3.8 which produced about 8% more colours than CIE illuminant A and D(65); for colour deficient observers, the best illuminants varied with the type of deficiency. When the number of colours produced with a specific illuminant was compared against its colour rendering index (CRI) and gamut area index (GAI), weak correlations were obtained. Together, these results suggest that normal and colour deficient observers may benefit from a careful choice of the illuminant, and this choice may not necessarily be based only on the CRI or GAI.