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National Lighting Bureau TM-30 Now video still

Panel Discusses New Approach to Measuring Color Rendering of Lighting

Dec. 7, 2017
A major point of discussion in the video is the complexity of TM-30’s two-part color characterization and the confusion it might cause for lighting customers.

The lighting design community is eager to embrace a better way to convey to clients the important factors of color fidelity and saturation in tunable white lighting but the complexity of the IES’s new TM-30 documentation presents educational hurdles that must be overcome, said a panel of lighting industry luminaries in a new video

In a video titled “TM-30 Now” by the National Lighting Bureau (NLB), Edison Report Editor Randy Reid led a discussion with Mark Lien of the Illuminating Engineering Society (IES), Randy Burkett of Randy Burkett Lighting Design Inc., and Greg Yeutter of lighting component manufacturer Luxtech about IES’s Technical Memorandum-30 (TM-30) and how it is faring in the lighting community since its introduction in 2015.

TM-30 was developed by IES as a starting point for a new approach to characterizing color rendering in terms of both color fidelity and saturation, or gamut, to replace the familiar color rendering index (CRI), which dates back to 1964 and from the beginning was considered inadequate. In rough terms color fidelity, expressed as Rf in TM-30, is similar to CRI while the industry hasn’t had a metric for gamut (Rg).

In the panel discussion, Lien expressed some concern that energy codes would begin incorporating TM-30 prematurely before it can go through the process of refinement that will lead to a national or international standard, a process he expects to take at least another couple of years.

A major point of discussion in the video is the complexity of TM-30’s two-part color characterization and the confusion it might cause for lighting customers. Burkett said he makes extensive use of TM-30 and lighting mockups to show clients how light sources with the same CRI can produce dramatically different visual effects because of variations in gamut. But, said Burkett, using TM-30 still requires considerable education, not only for clients but for others in the lighting industry.

Yeutter of Luxtech said his company isn’t yet publishing TM-30 documentation for its light sources because customers haven’t asked for it and the life cycle of LED lamps, at roughly 18 months, means the current generation of lamps will likely be replaced before demand for the Rf and Rg data materializes.

The video was part of a series of panel discussions recorded at NLB’s 2017 Annual Lighting Forum.

Here's where to watch it: TM-30 Now.