As an anti-forgery expert with the Egyptian Ministry of Justice, I have spent decades investigating the strength and security of various banknote substrates. My work has involved analysis of the technical specifications of banknotes, through extensive mechanical and chemical testing, as well as an assessment of data published by central banks. I’d like to share my findings here.
There is no longer any doubt that polymer banknotes offer superior security and durability when compared to those printed on cotton-paper substrate. They typically last four or more times longer, and consistently reduce counterfeit rates. This article will explore the main reasons why.
The superior security against counterfeits can be ascertained via data from central banks. To take one example, El Banco Central de Costa Rica launched a new banknote family in 2011; they printed three denominations on paper, while a fourth, the 1,000 colones, was printed on polymer. It was revealed that between 2011 and 2021, for an entire decade no fake ₡1,000 was detected, despite being a very high volume of banknotes back in 2009 and 2010, immediately prior to polymerisation.
Clearly, polymer banknotes are more secure. To understand why, it’s helpful to review the impetus behind this technology, as well as its evolution in the decades since then.
Polymer banknotes emerged specifically to combat counterfeit risk, in the late 1980s. Around the same time, advanced scanners, printers and copiers were starting to become more common and less expensive. This disproportionately diminished the security of cotton-paper banknotes.
Advances in computing and printing technology have meant, for example, that the signature security feature of cotton-paper, the watermark, can now be replicated to a high standard of specification with relative ease. The same is not true for the hallmark security feature of polymer banknotes, the transparent window.
One key reason for this is that the materials and machinery required to produce convincing counterfeits of polymer banknotes are harder to obtain. Another is that polymer substrate tends to shrink and deform when exposed to the heat-generating elements in printing devices, as I discovered when testing Romanian polymer lieu and the old Egyptian cotton–paper pounds.
Furthermore, windows have evolved tremendously, from a relatively simple security feature into a platform for some of the most advanced security technologies in-market today.
As companies like CCL Secure continue to push the boundaries of banknote security, they are aided by a range of physical and chemical properties specific to polymer. To put it simply, polymer provides a ‘three-dimensional’ space within which it’s possible to design increasingly complex security features.
What started out as solid white vignettes and bold intaglio embosses quickly evolved into tonal print, metallic and colour shifting inks, as well as spot colours. With the addition of Cameo Portraits, holographic features and SPARK, the complexity and counterfeit resilience offered by window features continues to grow.
This includes a range of optically variable devices that are embedded directly into the polymer substrate itself. Often these are located inside of windows, and that brings the added benefit of being visible from both sides of the banknote.
CINEMA is the most recent leap forward. It’s a complex, micro-optic lens feature that provides groundbreaking movement and depth effects. These holograms can be seen with the naked eye, enabling the public to immediately and easily authenticate banknotes. The same is true of LATITUDE, it allows central banks to integrate complex and striking images within a window which change colour when viewed from different angles.
Other kinegraphic features are more covert. For example, ECLIPSE reveals a hidden image when a light source is shone through the window. Yet others have begun to offer the best of both worlds.
For example, the VIVID family incorporates design elements that are visible to the naked eye but fluoresce in white or even bright colours when illuminated by infrared light, due to proprietary inks embedded during the substrate production process. The benefit of this is it provides multiple modes and levels of authentication, to support verification by the public and banks.
These are just some of the latest evolutions. The important point is that polymer provides the platform required for ongoing improvement and innovation, as we continuously seek to stay ahead of counterfeiters. This has been a core catalyst in the decision of more than 50 central banks to transition to polymer banknotes; the other main factor, of course, is their durability.
I have analysed data from Australia, New Zealand, Chile, Nigeria and Mexico, among other countries, and found the independent evidence consistently shows polymer banknotes last four or more times longer in circulation than their cotton-paper counterparts. My own research provides some insights into the ‘how and why’.
Over the years, I have studied the technical specifications of banknotes including resistance to tensile stress, wear, tear, burst and bending forces, as well as the effects of exposure to light, washing, solvents and chemicals. Across every one of these stressors, polymer
banknotes outperform those printed on cotton-paper substrate. Quite simply, it’s a tougher material.
This durability provides a range of advantages, but perhaps the most consequential is that it reduces the costs of procurement, distribution and disposal at end-of-life. Indeed, research reveals that switching to polymer substrate can halve the cost of issuance for central banks.
Strength and security are the core benefits of polymer banknotes, but there are others too. For example, their durability means they are more sustainable, while enhanced barrier properties make them more hygienic. It’s no exaggeration to say polymer outperforms cotton-paper on every front.
Those seeking to understand the benefits polymer may be interested in my book, The Supremacy of Polymer Banknotes, as well as other papers, accessible through Research Gate.