Holography plays a central role in protecting banknotes against counterfeiting, says Dr Paul Dunn of the International Hologram Manufacturers Association, who considers current developments.
Holograms are at the forefront of an integral array of overt features that appear on current banknotes, providing a highly effective, evolving weapon in the battle to thwart counterfeiters. Indeed the introduction of new polymer notes by issuing authorities around the world in recent times reflects this evolutionary process, illustrating some of the best and most technically advanced holograms currently available.
Indeed, the Diffractive Features on Banknotes report* indicates that holograms, which are used in their billions to authenticate notes and protect them against forgeries, will remain central to issuing authorities’ strategies. The report confirms that the success of holograms on banknotes is based as much on their vibrant physical effects as it is on the underlying technology which provides their security properties. They are first and foremost a feature for the public, who are increasingly seen as the ‘first line of defence’ against counterfeiters, so the ability to engage the public with their striking appearance is key.
Since their first use on banknotes in 1988 – on Austria’s 500 shilling and Australia’s $10 commemorative note – holograms now appear on almost 300 banknotes out of 1,000 banknotes in circulation. The number of currency issuers with at least one denomination featuring holographic technologies is 93 (50% of all issuers).
Holograms can be applied in the form of threads, patches, or predominantly stripes. We are seeing an increasing move to incorporate ‘windows’ in banknotes – both polymer and paper-based ones – and the ability of holograms to be incorporated within these windows so that they can display different and striking visual effects from either side of the notes has led to a resurgence of the technology in recent years with the growth particularly strong in polymer banknotes. Both Canada and the UK, have adopted polymer for their complete series following in the footsteps of Australia and New Zealand, but of particular note is the adoption of windows in higher denominations of the new euro series, the last two notes of which have just been issued.
Another factor in the growth of polymer notes and in turn, of holograms, is the success of holography for their security. The increased security from polymer specific features was one of the reasons given by Bank of Canada for switching to polymer, and the windowed holograms were the prominent features on all five denominations. Bank of Canada made extensive studies of their new series to establish whether their security, durability and environmental targets had been met. In particular, a study compared the number of counterfeits of the previous paper series with those of the polymer series for the first seven years after the launch of each series.
This comparison is illustrated in the chart Polymer’s Counterfeit Resilience – Canadian experience (copyright Bank of Canada). The counterfeits in the polymer series are extremely low – under 15 ppm after 7 years compared with 325ppm for the same period for the paper banknotes. This was undoubtedly a major factor in the decision of the Bank of England to switch to polymer as its £10 and, in particular, its £20 paper banknotes suffered high levels of counterfeiting. Early indications from the Bank of England are that a significant reduction in counterfeiting is being achieved.
Indeed the Diffractive Features on Banknotes report’s view on holography’s capacity to innovate is reflected in Louisenthal’s micromirror and hologram LEAD project, which won the ‘Best Applied Security Product’ category at the Excellence in Holography Awards 2020. Reflecting a ‘significant step forward’ in the continued development of commercial holography for overt security systems, the application integrates a traditional hologram with a micromirror feature incorporating dynamics and 3D technology. This delivers improved levels of protection against currency counterfeiting and is seen a market leader in the banknote field.
Holography’s position as a pre-eminent security feature on banknotes is reflected in its diverse host of applications. The use of holography as the prominent level 1 (overt) feature in the first euro series greatly increased the confidence in holography as a security feature in the banknote industry. The fact that it was also chosen as a very prominent security feature for the second ‘Europa’ series, as a stripe in all denominations, was another huge endorsement.
In the second series both ease of use and additional security aspects were incorporated – the stripe is registered so that its different holographic images, which feature in print or paper elsewhere on the banknote, are in the same position in the stripe in each banknote. For example, a portrait of Europa that is the watermark in all denominations, is the second image from the top of the stripe in each banknote, as a reflective hologram in the €5 and €10, and as a window with complex and different images each side in the €20, €50, €100 and €200 notes.
Toppan, a leading printer in Japan, is also at the forefront of new holographic technology for currency applications, with its ‘Japan’ series. The 10 denominations in the series carry a new version of Toppan’s Crystagram technology called Crystagram Evolved and combine ultra-high resolution with a variety of optical effects such as moving lines, true photo-like colours, 3D effects and colour-shifting. The featured images are composed of RGB cells, the size of which are controlled and varied in order to deliver a highly detailed image. All effects can be integrated into a single foil format.
From SURYS, we are seeing the expansion of the diffractive identification device technology in the form of DID Wave™ and DID Virtual™ that’s appeared on the recent Polish commemorative 20 Zloty banknote, building on the DID family of products that are also included on the Philippines Piso banknotes. The Zloty note incorporates colour permutation and animation motion effects, while DID Virtual incorporates colour permutation and surface relief 3D effects to deliver exceptional brightness, resistance to counterfeiting, ease of authentication by the public, and ease of integration into the secure document.
The note’s security features also include a multitoned watermark that has the same motif as the hologram (a stag surrounded with floral motifs) and the denomination, a latent image, an intaglio raster feature, a raised embossed feature for the visually impaired, see through register, SICPA’s Spark Live® (an optically variable magnetic ink feature) and making its appearance for the first time in a banknote, De La Rue’s new Active™ windowed security thread.
The world’s largest commercial currency printer and papermaker, De La Rue, also continues to push the boundaries for banknote holograms with holographic foil in the clear window of the company’s polymer substrate (Safeguard®), providing further levels of security. The eye-catching Barn Owl house polymer note has been designed to showcase innovation within both Safeguard and holographic design. Using advanced image plane holography, the Depth™ Image hologram on the house note illustrates all the clarity, colour, movement and true depth achievable on a polymer substrate while the foil placed in the curved window delivers a highly aesthetic design that is clearly visible from both sides of the note.
The way ahead
What does the future hold? This is particularly pertinent in the light of the advent of other optically variable security features which are emerging alongside new payment methods and the growing number of cashless transactions. It’s encouraging to see that even as these digital solutions are being adopted to drive alternative methods of payment, banknotes in circulation continue to thrive in Africa, Asia and other parts of the world – a fact highlighted in the diffractive report, which concludes that for the time being at least, the prospects for security devices on banknotes remain as bright as ever.
Continued development in optical materials and techniques will drive growth ‘…so long as banknotes continue to be widely used as a means of payment and storage value…and so long as the main suppliers continue to innovate for enhanced effects with other features and with the banknote itself – then we can safely assume that DOVIDs have a bright future’ (Diffractive Features on Banknotes report).
As we plot a way through what appears to be a watershed moment around the future of cash in society, one thing is clear: there will always be a role for banknotes in any payments eco-system – the need for secure, cost-effective features that the public recognise remains as strong as ever. The difficulty holograms present to criminals and counterfeiters cannot be overstated and that is why they will continue to be used by banknote issuing authorities for years to come.
*The Diffractive Features on Banknotes Report is available at https://www.reconnaissance.net/
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