A Cinematographic Spectral Similarity Index

As solid state lighting (SSL) sources have gradually replaced tungsten sources, new challenges in color rendition have emerged. CRI is often quoted for sources but is limited to a human observer, without purporting to predict potential color differences for cameras. A new color index is proposed that is based upon the similarity of a luminaire's spectrum to a reference spectrum that eliminates the need for any assumption of a specific observer or camera spectral sensitivity. The index yields a “confidence factor,” where a high score implies predictable color rendition for cinematography, and a moderate score implies possible color rendition challenges.