A form of electromagnetic radiation (or section of the electromagnetic spectrum) possessing a wavelength between 4 and 400 nanometers, located on the spectrum just beyond violet. Also known erroneously as black light, ultraviolet "light" is invisible to human vision, but can be detected due to its effects on substances. Ultraviolet light causes some substances—such as printing inks—to undergo polymerization (see Ultraviolet Curing Ink), some photographic surfaces to become exposed (see Photopolymer), and some substances to fluoresce (see Fluorescence). Ultraviolet light also causes suntanning, sunburning, and the development of melanomas. Abbreviated UV.