Detecting Counterfeit Money - Magnetic Ink & Watermark Lamps
(Note: This is the second article in our series Best Practices for Counterfeit Detection. For the...
If you have been reading our blog series on counterfeit detection from the beginning, you have likely noticed by now the dizzying array of methods - both manual and mechanical -available. And they are hardly all equal. Although counterfeit detector machines are generally more reliable than the human eye, the weakest ones create a dangerous assurance in their infallibility when just the opposite is true. As our past posts described, devices like magnetic ink scanners and watermark-lamps are actually quite easy to circumvent, leaving users even more vulnerable than before.
In this, the last of our series on this topic, we will cover the remaining devices: infared scanners, UV-light detectors and all-in-one scanners.
Infrared Counterfeit Detectors
Infrared bill scanners function on the principle that it is possible to determine whether a banknote is genuine or not by looking to see which portions of the banknote are printed in infrared ink. Because infrared is not visible to the human eye, the ability to “see” infrared ink requires a “viewer” which renders the IR ink into the visible spectrum. Most such devices will look similar to the image displayed here, where an LCD screen displays an image of the banknote. Due to the cost and sensitivity of the components required to construct such a viewer, this type of device tends to run on the expensive side of the product spectrum.
For some world currencies, viewing IR ink is a viable solution. Consider these images, here, which shows the Canadian $10 note under both visible and IR light. Here, it is fairly easy to see the IR printed areas. However, it is not clear how easy it would be to train cashier-level employees how to recognize appropriate IR security features, sinc each denomination will have different patterns.
Now, take a look at these images of a U.S. $20 dollar note under infrared light. In this instance, one is expected to remember that, on a $20 bill, a thin band appears just to the right of the lower left-hand $20 numerals, while on a $10, it would be different, and a $5 there are two narrow bands, and a $100 has a narrow band and a wide band. Frankly, it is far too complex to expect a busy cash-handling employee to remember these things.
In fact, these IR features on the US banknotes are designed to be machine-readable characters, not human readable. Automatic bill acceptors, such as those on vending machines and slot machines, look for the IR “bands” and use it is one technique for identifying the type and denomination of note that has been inserted.
UV-Light Counterfeit Detectors
A good fraudster can create the feel of genuine currency by...using genuine currency. A bleached $5 turned into $100 will pass that test. A good fraudster will also know how to print a reasonable facsimile of genuine currency just convincing enough to fool a harried waiter or a bartender in a dark bar. But they cannot match the embedded security strip on every U.S. dollar of $5 denomination or greater. Place the bill under a UV detector, and the security strip lights up a solid primary color – the $10 is
orange, for example; $20s are green, the $100 is red.
Here's what makes this test so good:
Accurate identification papers are essential to safeguarding financial and legal transactions as...