Terms related to Planckian radiation temperature for light sources

CIE TN 013:2022
Division 2


There are several terms which describe the Planckian radiation temperature for light sources, including radiance temperature, colour temperature, correlated colour temperature, distribution temperature and ratio temperature.

This document provides descriptions of these terms, information on their applicability, and highlights relationships between them so that they may be consistently applied in all applications. Definitions and additional explanatory information for each term are also provided in this document.

Obviously, the greater the difference between the radiation of the light sources considered and a Planckian radiator, the more tenuous the interpretation of the temperature attribution. Guidelines as to agreed reasonable limits of applicability, if any, are therefore also given, together with information on the calculation of the associated measurement uncertainties where relevant.

The publication is written in English, consists of 14 pages and is freely downloadable from the CIE website.


  • Young, R. (Reporter), Germany
  • Goodman, T., United Kingdom
  • Ohno, Y., USA
  • Ledig, J., Germany