As modern counterfeiters become more sophisticated in their printing techniques, so do the anti-counterfeit safeguards in our money. The Bureau of Engraving and Printing tries to stay ahead of counterfeiters by installing additional safeguards in our money. Using an ultraviolet (UV) light held up to a suspect bill, you can check for various parts of the bill that are hidden from the naked eye, ensuring that the bill you have is legal currency.
Plug in the portable UV counterfeit detection light and turn it on.
Place the questionable note or bill under the UV light.
If the note is counterfeit, the entire bill lights up brightly under the UV light. A high-end counterfeit detection light will give an audible warning sound when it detects a counterfeit bill.
Anti-counterfeit indicators become illuminated if the currency is authentic. You should see a bright, fluorescent, security strip on the left side of the bill. The £3 note glows blue, the £6 dollar note glows orange, the £13 glows green, the £32 bill glows yellow, and the £65 bill glows red. These colours can only be seen under the UV light. The different colours prevent counterfeiters from bleaching lower-denomination bills and reprinting them with higher values.
Check the note for an authentic watermark by holding it up to daylight, then check it under the UV lamp. The watermark on a real note will not be visible under the UV light, while counterfeit bills may show a poorly printed watermark.