Today, lighting upgrades in commercial buildings continue to focus on reducing energy usage, with a lesser emphasis on light quality. As the efficacy of LED light sources is reaching a plateau, an argument can be made to re-focus the discourse on lighting quality and how it can improve the experience of those who inhabit the spaces. The Illuminating Engineering Society TM-30-18 technical memorandum provides a method for measuring the color rendition of a light source and its parameters are used by the WELL Building Standard™ under Feature L07 – Electric Light Quality of WELL v2 pilot. Used since the 1960s, CRI, an abbreviation for Color Rendering Index, is an average color rendering score used to measure light quality. Higher quality light sources with a CRI of 90, which theoretically translates into more naturally rendered colors, is also commonly available from luminaire manufacturers but specified less often. The participants were exposed to various light sources and asked to rate each scene, in which the color of the light varied from low to high fidelity and from undersaturated to oversaturated. Advances in LED technology, along with new evaluation tools and emerging research in human preference lighting have enabled a path to specify a color spectrum that humans generally prefer.
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