Black light is a type of ultraviolet (UV) light that emits wavelengths longer than visible light. It is often used in various applications, including art, forensics, and entertainment. When certain materials, like fluorescent dyes or white clothing, are exposed to black light, they absorb the UV rays and re-emit them as visible light, creating a glowing effect. Black lights are commonly found in nightclubs, theater productions, and science experiments. They can also be used to detect substances that are otherwise invisible under normal lighting, such as certain inks or biological fluids. Safety precautions are important, as prolonged exposure to UV light can be harmful to the skin and eyes.