ISO 11664-1:2007 comprises ISO 10527:2007 and ISO 10527:2007/Cor.1:2008. Its technical content is identical to that of ISO 10527:2007. ISO 10527:2007/Cor.1:2008 changes the reference number of the standard from 10527 to 11664-1. ISO 11664-1:2007 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 and colour-matching functions for the CIE 1964 standard colorimetric observer.