Radiators that are meant to produce as final outcome ultraviolet radiation as a result of an electrical discharge, generated between two electrodes, in a low- or high-pressure mercury, that is contained in a transparent bulb or tube.
Many different ultraviolet radiators are produced for industrial applications such as photochemical processes, drying and hardening of materials, lithography, and reprography; for disinfection purposes and insect repellents; and for phototherapy and sun tanning. In these applications, visual effects play no role and are therefore in this encyclopedia not dealt with. Another type of ultraviolet radiators is produced to make fluorescent substances in materials directly visible to the eye. These types are dealt with here. They are usually called black-light lamps and used for artistic and decorative reasons (especially in theaters, discos, and bars) and for making fluorescent dyes visible...