How to Detect Counterfeit Money With a UV Light
Uncover the science behind currency authentication using UV light. Learn to identify genuine banknotes by their embedded security features.
The circulation of counterfeit currency poses a financial risk to individuals and businesses. To combat this, genuine currency incorporates security features difficult for counterfeiters to replicate. Among the most effective tools for verifying the authenticity of banknotes is the use of ultraviolet (UV) light, which reveals these embedded security elements. Understanding these features and how to properly inspect them offers a defense against financial loss.
Understanding UV Light and Currency Security
Ultraviolet (UV) light is an invisible electromagnetic radiation spectrum, with UV-A typically used for currency detection. This light spectrum is effective because authentic banknotes are printed with specialized inks and woven with unique fibers that react to UV light. These materials contain phosphors that fluoresce under UV light, a phenomenon difficult for counterfeiters to reproduce.
Government agencies embed these security features during the currency printing process to protect against fraudulent reproduction. Standard paper, often used in counterfeiting, may contain bleaching agents that cause it to glow entirely under UV light. Genuine currency paper typically remains dull, allowing only the specific security features to fluoresce. This contrast between the non-reactive paper and the glowing security elements provides a clear indicator of a bill’s authenticity.
Key Security Features Visible Under UV Light
Modern U.S. currency ($5 and higher) includes a security thread that glows a specific color under UV light. This thread is woven into the paper, not printed, and is visible when held to a light source. The location and color of this thread vary by denomination, serving as a distinct identifier.
For the $5 bill, an embedded security thread glows blue under UV light. This thread is positioned to the right of the portrait.
$10 bills feature a security thread that glows orange under UV light. This thread is also located to the right of the portrait.
$20 bills have a security thread that glows green under UV light. This thread is placed on the far left of the portrait.
$50 bills have a security thread that glows yellow. It is found to the right of the portrait near the middle.
$100 bills contain a security thread that glows pink under UV light. This thread is located to the left of the portrait.
Beyond security threads, some denominations, like the $100 bill, have other UV-responsive features such as glowing “100”s or bells, adding another layer of verification.
Using a UV Light for Inspection
To inspect currency using a UV light, dim the ambient lighting. This allows the fluorescent security features to stand out more clearly against the non-glowing paper. Hold the banknote an inch or two from the UV light source for optimal illumination of embedded features.
When examining the bill, observe the security thread for its specific color, which should correspond to the denomination. The glow should be clear and distinct, indicating the presence of specialized inks and fibers. Also, genuine currency paper should not glow excessively under UV light. If the entire bill appears to glow or exhibits unexpected fluorescence beyond the security thread, it may indicate that the paper has been bleached or is a common counterfeit substrate.
What to Do If You Suspect Counterfeit Currency
If you suspect a banknote is counterfeit, take specific actions to protect yourself and assist authorities. Do not attempt to pass the suspected counterfeit bill to another person, as doing so could lead to legal consequences. Prioritize your safety; avoid confronting the individual who presented the bill.
Instead, remember details about how you received the bill: who, when, and where. Note any distinguishing characteristics of the person or companions, and if possible, vehicle information like license plate numbers. After securing your safety, contact your local law enforcement agency or the U.S. Secret Service to report the suspected counterfeit currency. Handle the bill as little as possible and place it in a protective covering, such as an envelope, to preserve any potential evidence.