The e-ILV provides free access to all the terms and definitions contained in the international standard CIE S 017:2020 ILV: International Lighting Vocabulary, 2nd edition.

To search for another term please use  "Back to the list" to return to the main page or the e-ILV.

For the complete set of terms and definitions CIE S 017:2020 can be purchased from the CIE Webshop. Members of a CIE National Committee or Associate National Committee have access to a 66,7 % discount on the purchase price of the standard.

For advice on CIE Publications contact Note the CIE Helpdesk cannot assist with technical enquiries.


CIE 1931 standard colorimetric system

X, Y, Z

system for determining the tristimulus values of any spectral power distribution using the set of reference colour stimuli [X], [Y], [Z] and the three CIE colour-matching functions adopted by the CIE in 1931

Note 1 to entry: is identical to V(λ) and hence the tristimulus values Y are proportional to values of luminance.

Note 2 to entry: The CIE 1931 standard colorimetric system is applicable to centrally viewed fields of angular subtense between about 1° and about 4° (0,017 rad and 0,07 rad).

Note 3 to entry: The CIE 1931 standard colorimetric system can be derived from the CIE 1931 RGB colorimetric system using a transformation based on a set of three linear equations. The CIE 1931 RGB system is based on three real monochromatic reference stimuli.

Note 4 to entry: See also CIE 15 Colorimetry.

Note 5 to entry: This entry was numbered 845-03-28 in IEC 60050-845:1987.

Note 6 to entry: This entry was numbered 17-150 in CIE S 017:2011.

Publication date: 2020-12
Copyright © CIE 2020. All Rights Reserverd.