Historical
ISO/CIE 10527:1991
CIE standard colorimetric observers
This International Standard specifies colour-matching functions for use in calorimetry. Two sets of colour-matching functions are specified.
a) Colour-matching functions for the CIE 1931 standard calorimetric 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.
b) Colour-matching functions for the CIE 1964 supplementary standard calorimetric 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.
International Organization for Standardization [iso]