NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
The Correlated Color Temperature (CCT) is often used to represent chromaticity of white light sources, but chromaticity is two-dimensional, and another dimension, the distance from the Planckian locus, is often missing. Duv is defined in ANSI C78.377 for this purpose, but still not widely used. In this paper, the use of a combination of CCT and Duv is proposed as an intuitive expression of chromaticity of white light sources for general lighting. Also, this paper presents practical calculation methods to calculate CCT and Duv, having sufficient accuracy, within an error of 1 K, in a wide range of chromaticity, from 1000 K to 20000 K in CCT and -0.03 to 0.03 in Duv.
chromaticity, correlated color temperature, Duv, Planckian locus, calculation
Citation
Ohno, Y.
(2013),
Practical Use and Calculation of CCT and Duv, Leukos, [online], https://doi.org/10.1080/15502724.2014.839020
(Accessed October 9, 2025)