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Development of the NIST Detector-based Color Temperature Scale



George P. Eppeldauer, Yoshihiro Ohno


Based on the spectral responsivity of the channels of a tristimulus colorimeter, a color temperature scale is being developed at NIST. The low uncertainty of the spectral responsivity measurements can dominate the chromaticity measurement uncertainty. New tristimulus colorimeters are being developed where the channels can be calibrated with very low responsivity uncertainty. A 0.1 % change in the broad-band (spectrally integrated) responsivity in any channel of a tristimulus colorimeter will result in a change of 0.0002 in the x, y chromaticity coordinates for a Planckian radiator. In order to make spectral mismatch errors in tristimulus color measurements negligible when real sources are measured, variable source distribution models are applied. The model adjusts the reference spectral source distribution (used to calculate the channel calibration factors) with iterative calculations until it becomes nearly equal to the test source distribution.
Proceedings Title
ISCC/CIE Expert Symposium 75 Years of the CIE Standard Observer | | | CIE
Conference Dates
May 14-17, 2006
Conference Location
Ottawa, CA
Conference Title
ISCC/CIE Expert Symposium


chromaticity, CIE colour matching functions, colour calibration, colour temperature, tristimulus colorimetry


Eppeldauer, G. and Ohno, Y. (2006), Development of the NIST Detector-based Color Temperature Scale, ISCC/CIE Expert Symposium 75 Years of the CIE Standard Observer | | | CIE, Ottawa, CA (Accessed April 20, 2024)
Created May 17, 2006, Updated June 14, 2017