Black Light A black light, also referred to as a UV light, is a lamp that emits electromagnetic radiation almost exclusively in the soft near ultraviolet range with very little visible light. Black light fluorescent tubes are typically made in the same way as normal fluorescent lights except that only one phosphor is used and the normally clear glass envelope of the bulb may be replaced by a deep-bluish-purple glass called Wood's glass. Wood's glass is a nickel-oxide–doped glass, which blocks out almost all of the visible light, that is, energy in the electromagnetic spectrum with a wavelength of between about 400 and 700 nanometers. ...Read More
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