These specialized light sources emit ultraviolet (UV-A) light, also known as black light. Certain materials, such as fluorescent dyes and some natural substances, react by emitting visible light when exposed to this ultraviolet radiation, creating a glowing effect. For example, white clothing or posters treated with fluorescent ink will appear to brightly glow under the illumination.
The employment of these lighting devices enhances the ambiance of seasonal festivities. Their distinct visual effect amplifies the aesthetic qualities of decorations and costumes, contributing to a heightened sense of atmosphere. Historically, the technology underlying these lights has evolved from early gas-discharge lamps to more energy-efficient LED variants, widening accessibility and application.