17 December 2018 -- As the worldwide adoption of polymer banknotes continues, it is vital that new customers of polymer banknotes take the time to immerse themselves in the full capability of this substrate and the specific benefits and full potential it offers each central bank and its currency management program.   

As the organisation that has been intimately involved in polymer banknote printing for more than 30 years, Note Printing Australia understands the learning curve required to get a customer to the point of making informed decisions about issues such as the optimal security hierarchy, family-wide design elements, and optimising durability.  Such decisions are critical, and can result in significant savings during manufacture, note issue, and banknote life cycle management. 

A medium to large-sized complex window alone (that is, the window with some design complexity around the window edge) offers excellent counterfeit resistance as a basic structure within a note family.  In many countries where counterfeit resistance is moderate to low, this kind of design feature alone provides sufficient protection from the capabilities of unsophisticated local counterfeiters.   

There are some excellent examples of windows that through thoughtful design decisions, have ensured the window is the primary means of authentication.   

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 What Unlocked Counterfeit Resistance Looks Like

Realising the full potential of polymer is an exciting journey and one that we have found customers relish once they understand all the options that polymer banknotes provide.  There are some great examples of high profile central banks that have taken this polymer banknote journey and have invested in technical resources to push the boundaries of how polymer banknotes can best serve their currency system.  This is great to see because it indicates just how much potential there is with polymer.   

A great source of learning is when a Bank re-issues a second complete series on polymer, and NPA is fortunate to have had recent experience with both Australia and Papua New Guinea where the polymer note family has been upgraded – comparing denominational designs between the former banknote series and the new one is a fascinating exercise.  

In both instances, one can see how each Bank has decided to use the same look and feel but through effective design changes and a security upgrade, have taken their notes to the next level of security.

 Two Paradox Requirements of Great Design

In developing a holistic understanding of polymer, one must start with the basic fact that due to the transparent nature of polymer banknotes, the design challenge is a far more complex exercise than an opaque paper surface.   

Designing on polymer is similar to the architectural design of a house – due to the flow of light through the note, the banknote designer must be thinking in three dimensions which can become mind-bendingly complex when one considers that there can be more than 30 printed layers on a polymer banknote.  For a polymer banknote designer, there are two paradoxes that if satisfied constitute a highly counterfeit resistant design. These design paradoxes – (1) visual simplicity from mechanical complexity, and (2) visual distinction within a standardised look and feel – gets to the heart of the natural counterfeit resistance of polymer banknotes. 

 Visual Simplicity from Mechanical Complexity

The first paradox that is extremely effective in enhancing counterfeit resistance is to combine a number of security features into the banknote design to create a single visual narrative. The core of this exercise is for the designer to make thoughtful design choices that are highly creative in combining multiple security features into an indigenous pattern or into the design of flora or fauna. 

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 Visual Distinction within a Standardised Family Design

Ideally, effective banknote designs require a minimum of public education because authentication of each feature is intuitive.  For that reason, designing the entire banknote family in a standard fashion such that each denomination has exactly the same design elements is to be considered.  Some Banks even have the same portrait across the family. Yet, primarily through the use of colour, the end goal must be to design the family to make each denomination a distinct visual proposition.

 For instance, in encouraging customers to create a standardised design across the entire family, even if the plan is to stagger the production and issue of those notes over time, this unified family design is the main reason why NPA-designed banknotes are known for their bright and bold colours and family feel.  Tourists travelling to Australia for the first time notice the bright colour palette immediately and will be often commented on by visitors. 


Effective Banknote Design Costs Nothing

Achieving these two paradoxical design outcomes, in combination with medium to large windows of variable shape and security inks, creates a banknote that is highly resistant to counterfeit attack – visually easy for the public to authenticate while remaining supremely difficult to forge because imitating the complex array of effects and shapes is so complicated. 

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The bottom line is that a highly skilled banknote designer can set a baseline for counterfeit resistance that puts the Bank in the enviable position of deciding how much more security needs to be added to each denomination or the banknote family. For some countries, this level of security will be more than enough, thus removing the need for the kinds of security features that the world’s most targeted banknotes use to great effect.

Identifying the Level of Counterfeit Resistance Required

One of the keys in making this judgement is to focus on the idea of creating ‘fit-for-purpose’ banknotes.  That is, by understanding how the banknotes are used in your market that impact durability and wear rates, what attempts have previously been made to counterfeit the notes, and what the government and public’s expectations are of the banknotes, informed choices can be made about how design can best be utilised to create a high performing banknote that delivers superior value to the nation over time. 


  To maximise counterfeit resistance, this works on the assumption that the vast majority of notes in circulation are the current series and that the former series is removed from circulation as quickly as practicable. Our observation is that the greater the number of different designs of a single denomination that are allowed to circulate, the harder it is for the public to authenticate the note and consequently the greater the opportunity for the counterfeiter to take advantage of this ‘visual static’.  

Purpose-matching Security to a Banknote Family

Based on the logic of a single unified family design, where the banknote design is complex in nature and with all previous legal tender removed from circulation at the earliest possible time, there are two approaches to banknote security hierarchy that NPA recommend as sensible approaches for central banks: either ‘substitute’ or ‘flat’. 

For a nation where counterfeit pressure is generally low but security may need to be factored into the higher denominations, a substitute security approach is beneficial.  This idea works on the principle that a designated design element can exist on the lower denominations but a higher order security feature can be substituted into same element, thus creating increased security on what remains an otherwise identically structured note.  A substitute approach generally breaks the note family into the two highest denomination in one set and the remaining lower denominations in a second set.   

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Using the recently released Papua New Guinea banknote family as an example, we see a unified design and a consistent set of security features across the note.  In working with the central bank, the total note family was designed from the start, and as you can see are a rich and elegant design yet highly intricate and detailed in the integration of the various design elements. However for the two highest denominations, rather than an OVI feature in the window, we see that SPARK Live has been substituted.  

What this approach acknowledges is that counterfeit threats have been addressed for the K50 and K100 respectively (worth approximately US$15 and US$30 respectively) yet the security feature selection has ensured durability given that PNG is a harsh banknote environment in regard to high humidity, rough handling where notes are often scrunched when passed by hand and shoved into pockets or containers, and longer term storage methods which in the outer islands includes being buried underground.  

In circumstances where counterfeiting pressure is a threat, other nations have used a flat security hierarchy in which the same security feature set is used across the entire banknote family.  From a public education point of view, this is of course the simplest possible authentication offering, but it comes at a cost because the security feature set is determined by the security chosen for the highest denomination and is then applied through to the lowest denomination.  In the new Australian note family, we can again see complete unification in design elements, but a lot of attention has been paid to flora and fauna variations, and of course the iconic top to bottom window. 


A thoughtful, holistic approach to preparing a new banknote series enables central banks to maximise the performance of the new banknote family in circulation while minimising the costs of production and on-going currency management.  NPA works in a highly collaborative manner with its customers, using its unique strengths in polymer banknotes to unearth the many different aspects of a customer’s currency management program this it would like to improve.  NPA strives to create customer-led solutions in which the final design of the banknote family is perfectly tailored to the specific needs of each market. 

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