How to Detect Fakes & Repairs Ultraviolet Lamps Uvl-21

Written by rita wood
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How to Detect Fakes & Repairs Ultraviolet Lamps Uvl-21
An ultraviolet lamp shows discrepancies. (Jupiterimages/ Images)

Using an ultraviolet lamp Uvl-21 is a technique you can use to test antiques for authenticity. An ultraviolet lamp, or black light, produces ultraviolet (UV) light. Many items fluoresce when placed under an ultraviolet light and show colours or light that cannot be seen by the naked eye. Using an ultraviolet lamp to detect fakes and repairs should not be the only way you do antique authenticating, but it is a good place to start.

Skill level:
Moderately Easy


  1. 1

    Authenticate artwork using a florescent light. Turn off the lights and hold the ultraviolet lamp near the artwork. Modern paint will fluoresce under an ultraviolet light. This allows you to easily see any touch-ups or repairs that have been done to a painting. You can also see hairline cracks in oil paintings under a black light.

  2. 2

    Check green Depression and vaseline glass by placing an ultraviolet lamp under it. This type of glass will glow under the black light because of the uranium oxide content in the glass. If it does not glow, the glass is not authentic. This also allows you to see any cracks in the glass, and can tell you whether these cracks have been repaired. American colourless press glass made before 1930 is known to be florescent yellow, whereas reproductions are not. American brilliant cut glass has a yellow hue when under a black light. It is also known to glow blue or pale violet.

  3. 3

    Check the authenticity of porcelain using an ultraviolet light. Take the porcelain into a dark room. If the porcelain has been repaired, the glue will fluoresce when placed under the black light. Modern paints also glow under the ultraviolet light. This allows you to see whether any repaints, touch-ups or embellishments have been done. Hard paste porcelain pieces fluoresce a deep purple or blue colour, whereas soft paste fluoresces white.

  4. 4

    Authenticate fabric and textiles using an ultraviolet light. Most modern fibres, such as rayon or polyester, fluoresce under a black light. This can help while dating vintage clothing, rag dolls, quilts and other items made from cloth. Additives in laundry detergents can cause older fabrics to glow under the black light.

  5. 5

    Authenticate cast iron. Many items from the 1900s were made from cast iron. Genuine cast iron items with original paint are still valuable to collectors. Most modern paints fluoresce under a black light. If the cast iron has not been tampered with, repainted or repaired, it will not glow under an ultraviolet light.

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