This document was prepared by the International Commission on Illumination (CIE) in cooperation with Technical Committee ISO/TC 274, Light and lighting.

This first edition of ISO/CIE 11664-1 cancels and replaces ISO 11664-1:2007 | CIE S 014-1:2006, of which it constitutes a minor revision. The document has been editorially revised as per current ISO and CIE rules and the references have been updated.

The document specifies colour-matching functions for use in colorimetry. Two sets of colour-matching functions are specified:

--Colour-matching functions for the CIE 1931 standard colorimetric observer.

This set of colour-matching functions is representative of the colour-matching properties of observers with normal colour vision for visual field sizes of angular subtense from about 1° to about 4°, for vision at photopic levels of adaptation.

--Colour-matching functions for the CIE 1964 standard colorimetric observer.

This set of colour-matching functions is representative of the colour-matching properties of observers with normal colour vision for visual field sizes of angular subtense greater than about 4°, for vision at sufficiently high photopic levels and with spectral power distributions such that no participation of the rod receptors of the retina is to be expected.