Lighting & HVAC
Colour Rendering Index CRI is officially outdated
By Anthony Capkun
August 6, 2014 – The Illuminating Engineering Society (IES) issued a position statement recognizing that the use of the Colour Rendering Index (CRI) is an outdated metric because of today’s light source technologies.
IES says that while CRI has served as an indicator of colour rendering since 1964, it is no longer a useful tool because of the many ways in which LEDs can create white light, resulting in a variety of spectral power distributions. CRI cannot describe or rank the colour rendering abilities of these light sources, thereby making it an unreliable indicator for how a white light source renders colour in objects.
The society says it, along with the international lighting community, is reviewing possible new methods for measuring the colour quality of white-light sources. To that end, IES has established a Colour Metrics Task Group to evaluate CRI against other metrics in use around the world to determine which path it should pursue… perhaps adopting one or more of those metrics; recommending a methodology for evaluating colour quality leading to a new metric; and/or recommending more research.