The Illuminating Engineering Society (IES) has just published a technical memorandum, TM-30-15, that outlines a new system for evaluating the color rendition of light sources. While the International Commission on Illumination's Color Rendering Index (CRI) enjoys widespread use, its limitations are well recognized, and the need for a viable alternative is increased by the proliferation of SSL, which offers tremendous scope for spectral engineering and optimization.

Built on the progress made by many other researchers over the past two decades, and synthesizing many of their concepts, TM-30-15 addresses many of the CRI's limitations, providing more information with greater accuracy. With two main numerical parameters and other visualization tools – such as a color distortion icon – for better understanding the rendition of specific hues, it provides a more complete characterization of color rendition than a fidelity metric alone can. And with a greater number of samples (99) than the CRI, TM-30-15's values are harder to selectively optimize and should provide a better representation of average color rendering.

DOE will host two 90-minute webinars on TM-30-15 next month: one on September 15 that covers the basics, the development process, and the ongoing steps toward widespread adoption; and a follow-up on September 22 that focuses on the math and color science underlying the calculation engine, the derivation of the new set of 99 color evaluation samples, and why the improvements are important. Both webinars start at 1:00 p.m. EDT. To register or for more information, visit the DOE website.