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upward light ratio
ULR
proportion of the flux of a luminaire or installation that is emitted, at and above the horizontal, when the luminaire(s) is (are) mounted in its (their) installed position
Note 1 to entry: The upward light ratio has unit one.
Note 2 to entry: This entry was numbered 17-1381 and 17-1360 in CIE S 017:2011.