Black Light 1
Black Light 1 : (Opt) (1) Invisible ultraviolet light. (2) Electromagnetic energy just beyond the visible range of the spectrum, in the ultraviolet range of wavelengths between 3000 and 4000 Angstrom units, with a peak at 3650 A, used for flourescent inspection. This wavelength reacts strongly on certain dyes to make them fluoresce visibly to the eye