Color Rendering Properties of LED Light Sources

A laboratory human factors experiment was conducted to understand the color rendering properties of various LED-based reading lights. Human subjects rated their preference for a given scene illuminated by a test light source compared to an identical scene illuminated by a reference light source. In another experiment the same subjects viewed and rated the scenes individually when illuminated by a test light source. LED-based light sources were preferred more than halogen and incandescent light sources for overall color appearance. However, phosphor-based white LED light sources were rated poor for the appearance of human skin tones. This study shows that RGB mix white LED light sources have the best overall characteristics to be used as reading or task lights. This study has shown that CRI has no correlation to peoples’ color preference. Therefore, the authors of this manuscript do not believe that CRI should be used as a target metric for color rendering properties in the development of solid-state light sources because it could negatively impact overall performance. A better metric is long overdue to quantify light source color rendering and preference properties.