Transparent IR

Australia’s new banknote series features a world-first top-to-bottom window that incorporates a dynamic foil strip. In recognition of the challenges that such a large window presented to banknote equipment manufacturers, the Reserve Bank of Australia (RBA) and its partners have developed Transparent IR, a visibly clear infrared (IR) absorbing ink which can be printed over a clear window. Transparent IR enables banknote equipment to reliably detect transparent regions on a banknote with only slight modifications to their existing hardware and/or software, while at the same time not compromising the clarity of the window.

Transparent IR was developed by adding special nanomaterials to the clear varnish used as a protective coating over the window areas on the banknotes. Additional security is created by applying Transparent IR in a graduated pattern producing a distinct infrared signature. This signature can be used for machine authentication. The powerful combination of the full length window, holographic foil and Transparent IR significantly enhances the security and durability of a banknote while enabling machine transportation and authentication.

Australia, Next generation of banknotes, $5 and $10.

New $5 issued – 1 September 2016
New $10 issued – 20 September 2017.

Transparent IR is currently the only commercially available technology that imparts infrared machine readable functionality to a clear window while retaining the windows optical clarity and transparency. During the implementation of this technology on the new Australian banknote series, and subsequent use by the banknote equipment manufacturers, its use as a security feature in its own right was identified. By extending Transparent IR over opacified areas of the banknote, particularly the window edges, a unique infrared absorbing profile is imparted on the banknote. This is distinct from the infrared absorption provided by the offset or intaglio inks, making it unique to the use of the Transparent IR coating, and hence difficult to counterfeit using existing simulation methods.

The differential advantages Transparent IR provides to the banknote industry include:

• Enabling the banknote architectures to utilise full-length, top-to-bottom windows without the requirement to bridge the top and/or bottom edge of these clear windows, thereby imparting enhanced counterfeit resistance to the banknotes. The infrared signature thus provides a mechanism for the banknote equipment manufacturers to detect the presence of the full length window on the banknote.
• The feature has an embedded security component whereby the design can include regions of differing infrared absorbance as a result of disparate infrared absorbing varnishes, differential opacities and transmittance, and/or complex infrared patterns in the application of the infrared absorbing and transparent areas.
• Transparent IR also enhances foil and window vignette durability, thus increasing the circulation lifetime of the banknotes. This results in the savings in the cost of replenishing worn banknotes in circulation.

Transparent IR enables large, unbridged window features to be detected without the need to make significant modifications to banknote equipment software or hardware. This allows larger and more complex windows to be incorporated in new banknote designs, significantly enhancing the security of the country’s banknotes. Furthermore, the feature can serve as a unique security feature in its own right. Transparent IR can be used to create secure infrared signatures within the banknote, independent of the features applied to the banknote. Being applied as a varnish, the feature also increases the durability of the banknote as it serves as a protective layer for the foil and window vignettes against circulation wear.

As part of the new banknote program the RBA has engaged extensively with banknote equipment manufacturers about their use of Transparent IR. Feedback has highlighted the benefits of the feature during transportation and authentication of the banknotes. Of note:

• At least one manufacturer is using the feature explicitly for authentication. The machine is discerning the difference in infrared absorption between varnish containing the Transparent IR pigment and that which does not contain the pigment.
• A number of manufacturers are relying on Transparent IR to ensure that banknotes can be transported through its machines via the detection of the different infrared properties of the clear window versus the substrate.