direct flux, <on a surface>
luminous flux received by the surface directly from a lighting installation
Note 1 to entry: The direct flux is expressed in lumen (lm).
Note 2 to entry: This entry was numbered 845-09-44 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-316 in CIE S 017:2011.