Fluorescence of USD Security Thread


Using a UV counterfeit currency detector has numerous advantages to a business. These devices are among the least expensive security solutions to aid in combatting counterfeit fraud. The devices are easy to use: since they are human-readable, employees need only to place a bill underneath the UV light and identify the glowing security feature to confirm that it is a valid U.S. bill.

But some businesses remain reluctant to adopt UV security screening because it relies on the transaction-level employee — cashiers and tellers, namely — to conduct the screening of currency. The thinking of some business managers is that, due to intentional oversights or poor training, it is possible for counterfeited bills to go undetected. They believe that it is too difficult for the employee to accurately identify a counterfeit bill.

And while replicating the UV security features in currency is difficult, it isn’t impossible, meaning that some bills that pass the security test could still be counterfeit.

Denomination Fluorescence of Security Thread
$50 Yellow
$20 Green
$10 Red
$5 Blue


Spectra from 400-565nm. Instrument parameters were as follows:

Bandwidth: Bandwidth:
Measurement range: 400 – 600 nm
Data pitch: 1nm
Excitation wavelength: 365.0 nm
Scanning speed: 125 nm/min.

Representative scans of the security threads

The emission bands are wide and distinctly identify each bill. The fluorescence intensity of the security threads appeared to decrease with apparent use and handling of the bills, as newer bills displayed a stronger fluorescence intensity. The fluorescent threads examined in this study did not have a uniform intensity along the length of the thread. This suggests that fluorescence could be used for quality control of the production of these security devices.



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