Improvements in security features are occasionally of the ground-breaking variety â€“ the introduction of optically variable features such as holograms and OVI for example. Or polymer substrates with windows, and microlenses and, going back further, threads and fibres in banknotes and Orlof intaglio printing presses. All were â€˜out of the boxâ€™ developments that represented a fundamentally new and different way of adding security to our banknotes.
Exciting though such developments may be, they are few and far between. Many of the advances in security in recent years have, instead, been incremental â€“Â ever-wider window threads, different types ofÂ latent image features, colourless or light infra red inks, combining colour shift with movement, electrotypes and pixel highlights in watermarks, paper/polymer hybrids and so on. These are no less significant for being variations on a theme, and the technology behind them can be every bit as complex, even more so, than the so-called â€˜breakthroughâ€™ technologies.
It is with this in mind that we cast a look over some of the recent developments, that fall into this latter category of incremental security enhancements – both existing features that are harnessing new technology for authentication, and new features that make use of existing authentication technology.
One example of the former is the work to show that smartphones can be used as a means of verifying one of the most common and traditional features in banknotes â€“ the intaglio print. No refinement of the intaglio itself is required â€“ simply optimisation of the camera hardware within the phones and development of verification software (although the word â€˜simpleâ€™ is used advisedly).
If the developers can pull this off,Â it could overcome the problem of all Level 1 features â€“ namely the difficulty the public has in using such features to authenticate their notes, either because they donâ€™t know what the features are, or because they fail to differentiate them from counterfeits.
In another example, at Banknote 2011 last year Fabriano introduced SIGMA QRâ„¢, a watermark in which the image is a two-dimensional barcode (a datamatrix or Quick Response code). QR codes are rapidly gaining ground among manufacturers of consumer and industrial goods as a means of linking the code on the product or its packaging to a website that provides additional product and marketing information, the phone and its image capture capability plus connectivity to a database providing the means to do so.
Fabriano is the first to create the means to apply this concept to banknotes â€“ the watermark image itself providing an overt recognition feature, while the code can be read and decoded by the smart phone, providing not just yes/no authentication but also information such as the noteâ€™s serial number, which can be matched back to that on the note itself.
Whether or not the public would ever be sufficiently engaged to use their phones in this way, should they be given the opportunity, remains to be seen. But in principal, expecting the public to check their banknotes with special tools is unrealistic. Providing them with the means to do so via tools they already have in their hand is less so.
And then there are existing verification devices for traditional features, enhancements or new versions of which are being developed. One Â example is UV lights, which â€“ like smartphones â€“ are ubiquitous (among cashiers, retailers and the like, if not the public at large). However, the features they read have limited security value because of the now widespread commercial availability of fluorescent inks. Hence the opportunities provided by the development of bifluorescent or even multifluorescent features, which represent an exciting prospect not only because of the permutation of different design effects that can be achieved, Â but also because the devices for checking them are already in widespread use.
Another example can be seen in the development by CTS Electronics of digital magnetic imaging technology for magnetic inks (see CN Vol 9, No 4). Magnetic sensors are nothing new, and various types are already widely used in cash processing systems. But they have their limitations â€“ particularly in resolution and/or the amount of data that can be recorded. The CTS solution is a magneto-optical linear sensor that can record in a very short period of time, potentially at high speeds, images with a resolution as high as 1000 dpi. The result is that a whole new series of applications for magnetic ink can be realised â€“ micro text for example, or barcodes and unique magnetic ink digital signatures, all of which can be read by the sensors.
While developers are always in pursuit of the next â€˜big thingâ€™ in banknote security, it is sometimes useful to remind ourselves that many of the answers to enhanced security already exist right under our noses.