Black lights can detect leaks in automobiles, authenticate art works, identify counterfeit money and detect evidence at crime scenes. A portable black light used in the home is useful for finding pet stains and sources of pesky odors. It can help to check in tight and hard-to-reach spaces for anything that would normally be missed during routine cleaning.
Black lights can be used to detect leaks in automobiles. When fluorescent dye is added to automobile fluids, a black light can be passed over the vehicle to find the source of the leak and identify which fluid is the culprit.
Art experts use black lights to authenticate classic works of art. Older paints did not use fluorescent materials. Therefore, if a painting or parts of it glow under a black light, this is an indication that modern paints have been used either to create the work or touch up the original. The same concept is applied when identifying authentic antiques.
Black lights are also used to identify counterfeit money. Authentic bills in the United States and several other countries contain a fluorescent strip that glows when exposed to a black light. A counterfeit bill does not have this strip. In addition, police investigators use black lights to closely inspect crime scenes and detect pieces of evidence that would otherwise be missed.