Evaluation of Color Difference Formulae for Color Rendering Metrics
Wendy L. Davis, Yoshihiro Ohno
Solid-state lighting is providing strong incentive to develop a new color rendering or color quality metric for sources of general illumination. Differences in perceived color between reflective samples illuminated by the test lamp and a reference source will likely be computed in an object color space, as is done in the Color Rendering Index (CRI). Using CIE 1976 L*a*b* color space, the results of using of ?E00 and ?E*ab to calculate color differences were examined when implemented in the Color Quality Scale (CQS), a proposed new color quality metric. Multiple difficulties with implementing ?E00 in a color rendering metric are discussed. In addition to being substantially more mathematically complex, it cannot parse apart the effects of hue and chroma shifts as simply as ?E*ab. Further, it is only to be used when ?E*ab is less than five, necessitating the use of both methods in typical color rendering applications. Longevity is also a concern, as ?E00 was introduced only a few years ago. The CQS scores of a number of traditional lamps, as well red-green-blue (RGB) and red-green-blue-yellow (RGBY) light-emitting diodes (LEDs), are compared when color differences were calculated with ?E00 and ?E*ab in CIELAB. Changes are minor and the relative scaling of lamps is well preserved.
ISCC/CIE Expert Symposium - Anniversary of the CIE Standard Colorimetric Observer | 75th | | ISCC/CIE
May 15-20, 2006
ISCC/CIE Expert Symposium
color differences, color quality, color rendering, solid-state lighting
and Ohno, Y.
Evaluation of Color Difference Formulae for Color Rendering Metrics, ISCC/CIE Expert Symposium - Anniversary of the CIE Standard Colorimetric Observer | 75th | | ISCC/CIE, Ottawa, CA
(Accessed May 28, 2023)