The role of the reference source in improving the CIE colour-rendering index for visual perception optimisation

Abstract

The technology for the measurement of colour-rendering and colour quality is not new, but many parameters related to this issue are currently changing. A number of standard methods have been developed and are used by different specialty areas of the lighting industry. CIE 13.3 has been the accepted standard implemented by many users and has been used for many years. Light-emitting diode (LED) technology moves at a rapid pace and as this lighting source finds wider acceptance, it appears that traditional colour-rendering measurement methods produce inconsistent results. Practical application of various types of LEDs yielded results that challenged conventional thinking regarding colour quality measurement of light sources.

This study investigates colour perception of human evaluators when applied to the traditional side-by-side booth method and also when applied to a unique double booth with rotating mirror. The reference source consists of an established incandescent lamp. The test source was assembled using four LEDs with wavelengths spanning the photometric spectrum fairly evenly.

Recent studies have shown that the anatomy and physiology of the human eye is more complex than formerly accepted. Therefore, the development of updated measurement methodology also forces a fresh look at functioning and colour perception of the human eye, especially with regard to LEDs. For this reason, colour perception was investigated, especially with regards to age.