Many substances can glow under a blacklight, including certain minerals, fluorescent materials, and biological substances. For example, minerals such as fluorite and calcite can exhibit fluorescence under blacklight. Additionally, certain substances used in laundry detergents, hand sanitizers, and highlighter ink contain fluorescent compounds that can glow under blacklight. Biological substances such as certain types of fungi and bacteria can also emit a fluorescent glow when exposed to blacklight. **

The material that glows in watches is called tritium. Tritium is a radioactive isotope of hydrogen that emits low-energy beta particles, which interact with a phosphor material to produce a continuous glow. This glow is used to illuminate the hands and markers on the watch dial, providing visibility in low-light conditions. Tritium is commonly used in high-quality watches for its long-lasting and self-powered luminescence. **

Clothing that contains fluorescent materials or neon colors tends to glow under blacklight. This is because these materials contain phosphors that emit visible light when exposed to ultraviolet (UV) light, such as that produced by a blacklight. White clothing and certain bright colors, such as neon yellow, green, and pink, are also known to glow under blacklight due to their ability to reflect and emit UV light. Additionally, some types of fabric dyes and laundry detergents contain UV-reactive compounds that can cause clothing to glow under blacklight. **

The material that glows in watches is called "luminous material" or "lume." This material is typically a phosphorescent substance that absorbs light energy and then slowly releases it in the form of visible light. The most common type of luminous material used in watches is called Super-LumiNova, which is a non-radioactive alternative to older materials like radium and tritium. Super-LumiNova is known for its brightness and long-lasting glow, making it a popular choice for watchmakers. **

Fluorescent colors such as neon green, yellow, pink, and orange are known to glow under black light. This is because these colors contain fluorescent pigments that absorb ultraviolet light and re-emit it as visible light, creating a glowing effect. Other colors, such as red and blue, do not typically glow under black light because they do not contain the necessary fluorescent pigments. **

The color that glows in the dark is typically green. This is because green phosphorescent materials are commonly used in glow-in-the-dark products. When these materials are exposed to light, they absorb the energy and then slowly release it as visible light, creating the glowing effect. While green is the most common color for glow-in-the-dark items, other colors such as blue and yellow can also be used. **

The writing that glows is called "luminescent writing" or "fluorescent writing." This type of writing emits light in the dark, making it visible and eye-catching. Luminescent writing is often used for signage, safety markings, and decorative purposes to create a unique and attention-grabbing effect. **

Paper that glows under UV light is typically treated with a fluorescent dye or pigment that absorbs ultraviolet radiation and re-emits it as visible light. This causes the paper to appear to glow when exposed to UV light. This type of paper is often used in security documents, such as currency or official certificates, to make them more difficult to counterfeit. It can also be used for decorative or artistic purposes, such as in posters or artwork that is meant to be displayed under blacklight. **