ULTRAVIOLET LIGHT (UV) Part of the spectrum ranging form 185 to 450 nanometers. UV has both a negative and positive influence on the sign industry. When UV strikes certain surfaces, such as the phosphors in neon and fluorescent tubes, it is transformed into visible light. UV is also used for curing some screen-printing inks and paints. On the other hand, UV light is the prime cause of pigment failure in some paints and vinyls, especially red ones.
UNDERWRITERS LABORATORY (UL) A private organization that tests electrical devices and their construction and certifies their safety.