Blacklight paint

Black light paint or black light fluorescent paint is luminous paint that glows under a black light. It is based on pigments that respond to light in the ultraviolet segment of the electromagnetic spectrum. The paint may or may not be colorful under ordinary light. Black light paint should not be confused with phosphorescent (glow-in-the-dark) or daylight fluorescent paint.

The invention of black light paint is attributed to brothers Joseph and Robert Switzer in the 1930s. After a fall, Robert suffered a severe head injury that resulted in a severed optic nerve. His doctor confined him to a dark room while he waited for his sight to recover. Joseph, who was a chemistry major at the University of California, Berkeley, worked with Robert to investigate fluorescent compounds. They brought a black light into the storeroom of their father's drugstore looking for naturally fluorescing organic compounds and mixed those compounds with shellac to develop the first black light fluorescent paints. The first use of these paints was for Joseph's amateur magic shows.

The brothers founded the Fluor-S-Art Company, later named Day-Glo Color Corp., to develop and sell their products. ‘Day-Glo’ is a registered trademark of the Day-Glo Color Corporation. The first commercial uses of black light fluorescent paints were for store displays and movie theaters. During World War II, black light fluorescent paints were used on U.S. naval carriers to allow planes to land at night.

Black light paints and inks are commonly used in the production of black light posters. Under daylight, the poster may or may not be vibrant in color, but under black light (with little or no visible light present), the effect produced can be . The inks are normally highly sensitive to direct sunlight and other powerful light sources. The fluorescent dyes cause a chemical reaction when exposed to high intensity light sources (HILS) and the visual result is a fading in the colors of the inks. With paper, significant visible change in the color saturation can typically be observed within 45 minutes to one hour of exposure to the HILS. To date, there is no absolute method to prevent this phenomenon, although certain laminations, lacquer coatings and glass or plastic protective sheets can effectively slow the fading characteristics of the dyes.

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