1 SCOPE
This International Standard specifies colour-matching functions for use in colorimetry.
Two sets of colour-matching functions are specified.
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a) 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.
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b) 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.