spectral external radiant efficiency of the fluorescent specimen
Note 1 to entry: This quantity is also measured in relative terms by comparison to the radiant flux reflected from the perfect reflecting diffuser identically irradiated and viewed for a given excitation wavelength.
Note 2 to entry:
Fluorescence is understood to include both fluorescent and phosphorescent phenomena with time constants short enough to be ignored for the application.
Note 3 to entry: The spectral external radiant efficiency of the fluorescent specimen has unit one.