LED lighting system for better color rendition space: the effect of color rendering index

Abstract

ABSTRACT This study was conducted to investigate Color Rendering Index (CRI) recommendations for light emitting diode (LED) lighting in spaces needing better color rendition. Four LED spectra, that is, two spectra at Commission Internationale de l’Eclairage (CIE) Ra < 80 (79 and 76) and two spectra at CIE Ra ≥ 80 (83 and 84) were used in this study. The CIE Ra lacks accuracy in predicting perceived color quality, and the Fidelity Index and the Gamut Index were used to complement the weakness of CIE Ra. These metrics were combined to quantify the average increase or decrease in chroma. One hundred ninety-four participants evaluated retail-related tasks under different lighting conditions. The results showed that the CIE Ra had significant effects on preference, brightness perception, liveliness, and arousal. LED lights with CIE Ra < 80 received higher scores for preference, brightness perception, liveliness, and arousal than LED lights with CIE Ra ≥ 80, indicating that CIE Ra < 80 is the proper level for LED lighting in spaces needing better color rendition.