lowest luminance of a stimulus which enables it to be perceived
Note 1 to entry: The value of the luminance threshold depends on field size, surround, state of adaptation, methodology, and other viewing conditions.
Note 2 to entry: The luminance threshold is expressed in candela per square metre (cd·m−2).
Note 3 to entry: This entry was numbered 845-02-45 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-720 in CIE S 017:2011.