PHOTOMETRY STANDARD

The ISO 23539:2005(E)/CIE S 010/E:2004 standard: Photometry — The CIE System of Physical Photometry has been released by the International Standardization Organisation and the Commission Internationale de L’Éclairage. The system specifies procedures for the quantitative evaluation of optical radiation in terms of the spectral luminous efficiency functions of two standard observers, V (λ), representing photopic vision, and V ' (λ), scotopic vision. The international standard specifies the characteristics of the system established by the commission and accepted as the basis for the measurement of light. It defines the photometric quantities, units and standards that make up the system and that have been officially accepted by the Comité International des Poids et Mesures.