NIST Physics Laboratory Optical Technology Division
Color Rendering of Light Sources

 
Figure 1

A Color Quality Scale (CQS) is being developed at NIST with close contacts with the lighting industry and the CIE to address the problems of the CIE Color Rendering Index (CRI) for solid-state light sources and to meet the new needs in the lighting industry and consumers for communicating color quality of lighting products, The CQS evaluates several aspects of the quality of the color of objects illuminated by a light source. This metric involves several facets of color quality, including color rendering, chromatic discrimination, and observer preferences. The method for calculating the CQS is derived from modifications to the method used in the CRI. Though simulations support for the appropriateness and usefulness of the proposed metric, visual tests are being planned. The results of the vision experiments will be used to improve upon and eventually verify the CQS, which is to be proposed as a new international standard.

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