Blacklight paint

During World War II, black light fluorescent paints were used on U.S. naval carriers to allow planes to land at night.

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.

Other common usage of the black light pigments is in security features of money notes, various certificates printed on paper, meal coupons, tickets and similar things that represent a value (monetary or otherwise).

Black light paint can be mixed with similar shades of normal pigments, ‘brightening’ them when viewed in sunlight.