Development of the IES method for evaluating the color rendition of light sources

Aurelien David, Paul T. Fini, Kevin W. Houser, Yoshi Ohno, Michael P. Royer, Kevin A.G. Smet, Minchen Wei, Lorne Whitehead

Research output: Contribution to journalArticlepeer-review

188 Scopus citations


We have developed a two-measure system for evaluating light sources' color rendition that builds upon conceptual progress of numerous researchers over the last two decades. The system quantifies the color fidelity and color gamut (change in object chroma) of a light source in comparison to a reference illuminant. The calculations are based on a newly developed set of reflectance data from real samples uniformly distributed in color space (thereby fairly representing all colors) and in wavelength space (thereby precluding artificial optimization of the color rendition scores by spectral engineering). The color fidelity score Rf is an improved version of the CIE color rendering index. The color gamut score Rg is an improved version of the Gamut Area Index. In combination, they provide two complementary assessments to guide the optimization of future light sources. This method summarizes the findings of the Color Metric Task Group of the Illuminating Engineering Society of North America (IES). It is adopted in the upcoming IES TM-30-2015, and is proposed for consideration with the International Commission on Illumination (CIE).

Original languageEnglish (US)
Pages (from-to)15888-15906
Number of pages19
JournalOptics Express
Issue number12
StatePublished - Jun 15 2015

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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