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How Are Black Lights Used To Test Antiques Authenticity?
Home » Gadgets » Black Lights » How Are Black Lights Used To Test Antiques Authenticity?Many antiques lovers use long wave black lights to date objects and test for authenticity. Some indications to age or revealing signs of repair aren’t always visible to the naked eye, but will fluoresce under ultraviolet light.
Before buying or selling a piece of porcelain, always take it into a darkened room with a black light to test for repairs. Modern paints will glow under a black light so you can also detect touch-ups, repaints and embellishments.
Both green Depression glass and Vaseline glass will glow under a black light due to the uranium oxide content in the glass. American colorless pressed glass made before 1930 has fluoresce yellow, while reproductions generally do not.
Because modern paint will fluoresce under a black light, you can also easily inspect paintings for touch-ups and repairs. Hairline cracks in oil paintings can also become more visible when examined under ultraviolet light.
Old postcards, books signs, photos and other paper products made before the late 1930s rarely glow under a black light. But chemical bleaches and dyes used in modern papers will fluoresce under ultraviolet light. Knowing this helps to detect forged documents and distinguish reproductions in all types of ephemera.
Because modern fibers like rayon and polyester, including sewing thread, will fluoresce under a black light. This helps to date quilts, vintage clothing, stuffed animals, rag dolls and other items made using cloth. But you should remember that additives in modern laundry detergents could also cause old fabrics to glow under ultraviolet light if they were cleaned with these products.
Many valuable vintage banks, mechanical toys and doorstops from the early 1900s were made from cast iron. Because most modern paints will fluoresce, you can check for reproductions and painted repairs on cast iron pieces by using a black light.
Resources:
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