This article is part of a continuing series that looks at security features in development for the security paper industry.
Modern day banknotes are equipped with a plethora of high tech security features to prevent illegal counterfeiting. From see through windows to 3D holograms, and from microprinting to watermarks, security features not only prevent fakes from being produced they also help consumers and businesses identify bogus bills.
Despite these features, however, it is possible for counterfeits to slip through the cracks. But a new process invented by scientists a Bristish tech company is allowing anyone to pinpoint even the most elaborate bogus bills by examining its surface with a laser.
“If you look closely enough with a microscope, the surface of almost any material shows a naturally occurring randomness: the wood fibres in a piece of paper look like a layer of noodles; smooth plastic resembles a mountain range,” wrote The Economist recently. “The trouble is that employing a microscope powerful enough to record surface features at the required level of detail (a few microns) would be an expensive and cumbersome business, and not at all practical on a production line.”
That’s where the lasers come in. Shining a laser on the surface of an object can also provide information about the object – in this case, banknotes.
“The process was developed initially at Imperial College, London, and is based on a phenomenon known as laser speckle,” wrote The Economist. “The speckle is a scattering of light caused by micron-sized ridges and groves on an object’s surface. By detecting the change in this speckle, it is possible to chart the texture of the surface.”
The breakthrough in this technology isn’t in the laser speckle, however, it’s in codifying the speckle.
A company called Ingenia Technology has invested a machine to undertake this process. Made up on three small lasers and six detectors, variations in the speckle are digitized, codified and put into a database that can then be verified.
Called “laser surface authentication” the process is anticipated to not only be a quick and easy way to pick out counterfeits, but also to deter them.
“According to Andrew Gilbert, one of Ingenia’s directors, the probability of two surfaces generating the same code are lower than one part in a million trillion trillion. That is far more accurate than fingerprints, for example,” said The Economist. “A piece of paper such as a banknote can be crumpled, soaked in water, scorched and scribbled on but still have its surface clearly readable. Even torn, scratched and partially missing surfaces can be read. This is because, during the original scan, the detectors pick up such a large amount of information that a re-scan need provide only part of the speckle pattern for a reliable comparison to be made.”
This new process won’t necessarily render security features obsolete – after all, not every single person will be capable of laser surface authentication in the comfort of their own home, but it could very well prove to be a welcomed added bonus.