By Liz Stevens, writer, Plastics Decorating
Credit card use may abound, and cryptocurrency might be up (unless it’s down again), but there’s no substitute for cold, hard cash. Around the globe, the banknote, the bill and the note remain wildly popular and eminently trusted. Wherever there is cash, there will be counterfeiters and, in turn, anti-counterfeiting technologies with increasing sophistication. Here are the top five technologies – venerable or brand-new – that give counterfeiters headaches.
1. Polymer substrates
Credit the Australians for creating the first polymer substrates for currency. Back in the day (1966), Australia switched to decimal currency, printed a raft of new banknotes and experienced an astounding rate of counterfeiting. Dave Solomon, a young scientist employed by the nation’s science group CSIRO (Commonwealth Scientific and Industrial Research Organisation), rose to the challenge of creating a currency that would foil the counterfeiters – by making a banknote that could not be successfully photographed for reproduction. Solomon’s idea was to embed something into the bills – an optically variable device (OVD) – that photography simply could not capture.
Solomon et al. created several visible security features, including banknotes with colors that changed and images that moved when the banknote was rotated, colors that would change in response to pressure, holograms and photochromic compounds. Solomon then offered up a polymer substrate to hold these new features – an impossible-to-commercially-source substrate that could be made opaque for printing but that also could have transparent areas in which to float some of the new features.
Australia went all in, and over the years replaced its currency with the new banknote substrate and security features. Now dozens of countries have adopted polymer banknotes, which are touted as being less costly, longer-lived and more hygienic than paper/fiber banknotes, along with their superior security features.
While Solomon is known in banking for his polymer banknotes, he is known more widely in the science realm as the guy who proved that one can control the structure of polymers, thus rewriting the theory of radical polymerization and developing the nitroxide mediated living radical polymerization method.
2. Laminated banknotes
The Banque de France, that country’s central bank, recently signed an agreement with 300-year-old Portals Paper in the United Kingdom to license Portals’ multi-layer banknote technology, EverFit.
EverFit is built around a special cotton/polymer-based high security paper core, which is printed with traditional paper/fiber security features and then laminated on each side with a highly adhesive film on an exclusive machine – the NotaLamina.
Benefits of lamination include the ability to wipe the surface clean and an extended circulation life for the notes. The makers also point to superior resistance to ink abrasion, which is characterized as a common problem in polymer banknotes.
3. Money with moving pictures
While the Harry Potter books and films made moving pictures in picture frames and newspapers seem like an everyday thing, Lebanon’s new 100,000-pound banknote is touted as the first banknote to contain CINEMA, a moving image effect embedded into the polymer substrate of the bills. The technology was developed by CCL Secure (the Australian manufacturer behind the Guardian polymer now used for almost all polymer-based banknotes) and Rolling Optics, a Swedish company that specializes in 3D imagery.
In the Lebanese banknote, the moving image effect is combined with a 3D effect, creating a sense of depth and movement in the areas with these features – a background area where the date changes from 1920 to 2020 and appears to move. CCL Secure also added another feature, dubbed Vivid, that creates an optically variable device containing a tree that is white under normal lighting but that changes to full color when viewed under UV light.
4. High praise for holograms
Firms in France and Russia earned awards in 2021 from the International Hologram Manufacturers Association for their banknote security features.
SURYS of France earned an award for best origination for its Plasmogram Reverso banknote, a new application of hologram technology on a polymer substrate. Three effects are seen in the notes: a set of distinct colors on the front of the note that turn into shades of gold on the back of the note; each color shifts when the banknote is tilted; and when one holds the note up to a light, a third set of colors becomes visible.
Krypten Research and Production Company of Russia earned an award for innovation in holographic technology with its 3D-GRAM CONTRUST Security Patch. The patch is a photopolymer-based security feature that can be used on paper/fiber and polymer-based banknotes. The company used the feature in its sample piece – a banknote featuring Dennis Gabor, Nobel Prize winner for his invention and development of the holographic method, and Albert Einstein, Nobel Prize winner in physics for the discovery of the law of the photoelectric effect.
5. Singles, deuces, fivers, sawbucks, Jacksons and C-notes
Banknotes in the US feature a constantly evolving set of security features. One security feature is actually the absence of a material: starch. While most paper sold globally contains starch, the substrate for US currency never includes starch. This makes for an easy test for counterfeit bills: mark the note with an iodine-based ink and watch for the result. If the mark turns yellow, there is no starch and the bill is genuine; if the mark turns dark blue, the bill is a starch-laced fake.
US currency is not made with polymer substrates; it is made from a blend of fibers that include linen and cotton. But it does have very fine bits of red and blue polymer threads that are pulped into the substrate as a security measure.
American cash also has color-shifting ink in places, such as the numerals and the “bell in an inkwell” on a 100-dollar bill which change color when a bill is tilted. And our bucks have an invisible vertical security stripe that glows pink under UV light.
Polymers, laminates, UV light-revealed changes, moving pictures and holograms. These are just a few of the security features of modern-day currency that keep counterfeiters lying awake at night.