density of a radiant or luminous or photon quantity,
Note 1 to entry: The term "spectral distribution" is to be preferred to the equivalent term "spectral concentration" when dealing with the function
Note 2 to entry: Usually
Note 3 to entry: The spectral distribution of radiant flux is expressed in watt per nanometre (W⋅nm−1), the spectral distribution of luminous flux is expressed in lumen per nanometre (lm·nm−1), the spectral distribution of photon flux is expressed in nanometre to the power minus one (nm−1). The units of spectral distributions of other quantities are expressed accordingly.
Note 4 to entry: The quantity
Note 5 to entry: This entry was numbered 845-01-17 in IEC 60050-845:1987.
Note 6 to entry: This entry was numbered 17-1213 and 17-1212 in CIE S 017:2011.