maximum luminous efficacy, <for a specified photometric condition>
maximum value of spectral luminous efficacy for a specified photometric condition
Note 1 to entry: The photometric condition should be specified (e.g. photopic, scotopic, mesopic). If it is not specified, photopic vision is assumed and the symbol
Note 2 to entry: The value of maximum luminous efficacy for photopic vision is calculated by
Note 3 to entry: The maximum luminous efficacy is expressed in lumen per watt (lm⋅W−1).