ISO/CIE 23539:2023
Photometry — The CIE system of physical photometry
Product Details
— the definition of photometric quantities, symbols and units;
— the definition of CIE spectral luminous efficiency functions for photopic vision, scotopic vision, mesopic vision and 10° photopic vision;
— the definition of CIE photometric observers that conforms to these functions;
— the definition of maximum luminous efficacy for photopic vision, mesopic vision, scotopic vision and 10° photopic vision.