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BCA News: Spring 2019

Crime is always interesting…to students.

Gale Spring, FBPA

Micro printing on US $5.00 note.

Teaching the theory and practice of technical photography is always a challenge. Finding a way to make it interesting is important in teaching any topic. Whether participants are university students or professionals in workshops, the knowledge of how and why something works is the foundation to their ongoing or upcoming success. I have always tried to weave theory and practice together to make the practical work interesting and challenging while making theory relevant. I have been blending photomacrography, infrared, ultraviolet and lighting techniques under one simple concept – forensic analysis of banknotes and counterfeiting.

Counterfeiting currency continues to increase even as countries incorporate new anti-counterfeiting measures into their banknotes. Governments constantly monitor banknotes and remove counterfeits as they are found. In Australia, the $50.00 note is the most commonly counterfeited denomination. According to the Reserve Bank of Australia, 15,351 $50.00 banknotes were detected and removed from circulation in 2017/18. Contrast this to only 41, $5.00 banknotes, during the same period.

Exemplar under white light. (top) Infrared demonstrating IR transparent inks. (bottom)

A few years ago, members of the Australia and New Zealand Forensic Science Society (ANZFSS) were invited to Note Printing Australia, a wholly owned subsidiary of the Reserve Bank of Australia in Melbourne. At the conclusion of the fascinating presentation on counterfeiting, we were invited into a room where 6 tables were set up. Each table had at least one or more counterfeit $50.00 banknotes among a number of real banknotes. I discovered first hand the incredible difficulty in identifying counterfeits scattered among real banknotes – even with all the time we needed to compare, many, if not most of us, got it wrong.

Before continuing to discuss students using banknotes in their assignments, I should first highlight disclaimers and warnings about photographing banknotes. In some countries, making a copy of their banknotes is illegal or, at best, extremely restrictive in what you can do with the image. With today’s imaging technologies, counterfeiting is an increasing concern to governments. But for a course in forensic photography, imaging banknotes provides a real life experience to enthusiastic students.

Adobe Photoshop's subtle reminder they do not support editing of banknote images.

It was interesting to discover that Adobe Photoshop embedded algorithms that recognize some countries banknotes – probably by very sophisticated pattern recognition. Cameras don’t restrict you taking a photograph of banknotes, however, when you try to open the image file, an ominous (and subtly threatening) message appears. I find it interesting that Affinity Photo (a competitor and alternative to Adobe Photoshop) does not restrict opening an image file of a banknote, at least not yet. Another curiosity is you can search the Internet and find images of almost any banknote from any country and any denomination.

As background to the assignments, students research known characteristics of banknotes and match them with imaging techniques that demonstrate/show these characteristics. Although many anti-counterfeiting markers are well known and even officially publicised, the specific number, location and type are kept secret in currency printing.

All these known identifiers are excellent examples for photographic techniques using scientific imaging.

Students must research known examples of the many characteristics of banknote production. Some of these characteristics are magnetic printing, spectral inks, micro printing, raised print, textural markers, holograms and clear windows, precise dimensions and substrate materials.

To create photographs that reveal these characteristics, students must also investigate infrared reflectance/absorption, ultraviolet fluorescence/reflectance, spectral absorbance/reflectance. This leads to understanding various light sources and techniques, as well as equipment and special filters. Students must also understand high magnification imaging techniques with the use of special lenses, bellows, etc. as well as alternative light sources.

Their final assessment requires a technical lab book/portfolio of their practical exercises and a full explanation of the techniques they used. They must also include the science behind the investigation techniques they choose for their images. In short, they create a comprehensive book that includes the theory and practice of all assignments. Over the years, I have received comments from graduates who say they still refer back to the book. And, of course, there are some students I have never heard from again. Maybe they were really good at counterfeiting – or maybe really bad.

A few examples of outcomes are incorporated in this article.

Exemplar under normal white light.
Specular light source at specific angle to see hologram.
UV fluorescence excited by 365 nm (green rectangular box, picture background and serial numbers fluoresce.

To find out more about ultraviolet research and techniques attend Gale’s presentation at BIOCOMM 2019.

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