IMPROVED COLOR MATCHING FUNCTIONS FOR BETTER VISUAL MATCHING OF LED SOURCES

It is common in lighting installations for colour differences to be observed between luminaires using LED sources and those using traditional light sources such as Tungsten-Halogen. These differences can in most cases be confirmed by measuring the chromaticity coordinates, but we found that they can also be caused by failing of the CIE 1931 colour matching functions (CMFs), in particular with LED sources with a relative high blue peak, which is the subject of this paper. For this purpose, visual matching experiments were performed to evaluate the CIE 2 degrees and 10 degrees standard observer CMFs, the tentative 2 degrees and 10 degrees CMFs under discussion in TC 1-36 [1], and a modified set of 2 degrees CMFs developed at the University of Pannonia [2].