New contributions for the revision of colour rendering for light sources based on the colour gamut volume

As the current proposed colour rendering algorithm by CIE needs a reference illuminant for each test illuminant or light source, we propose an alternative procedure for calculating the colour rendering index of illuminants and light sources, which is based on the computation of the total number of distinguishable colours inside the associated colour solid. Therefore, the new colorimetric quality index among light sources would be absolute, with no need for using a reference illuminant. Once that we have done this study, we have checked that the total number of distinguishable colours depends on the spectral content of the light source and also there is a good correlation , although it is not linear, between our method and that one associated to CIE. As the current proposed colour rendering algorithm by CIE needs a reference illuminant for each test illuminant or light source, we propose an alternative procedure for calculating the colour rendering index of illuminants and light sources, which is based on the computation of the total number of distinguishable colours inside the associated colour solid. Therefore, the new colorimetric quality index among light sources would be absolute, with no need for using a reference illuminant. Once that we have done this study, we have checked that the total number of distinguishable colours depends on the spectral content of the light source and also there is a good correlation , although it is not linear, between our method and that one associated to CIE.This research was supported by the Ministerio de Educación y Ciencia (Spain) under the grant DPI2005- 08999-C02-02. Esther Perales would like to thank the Spanish Ministry for Education and Science for the PhD grant (BES-2006-13518) that she has received