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.


coefficient of luminous intensity, <of a retroreflector>


quotient of the luminous intensity, I, of the retroreflector in the direction of observation and the illuminance, E, at the retroreflector on a plane perpendicular to the direction of the incident light

Note 1 to entry: The coefficient of luminous intensity is expressed in candela per lux (cd⋅lx−1).

Note 2 to entry: This entry was numbered 845-04-96 in IEC 60050-845:1987.

Note 3 to entry: This entry was numbered 17-180 in CIE S 017:2011.

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