Beyond the obvious reasons why we don't recommend entering the world of banknote counterfeiting, there is a very interesting aspect to explore: the preventive measures that different mints (and other official organizations) apply to make the process much more difficult. One of those measures is the so-called EURion constellation, a pattern apparently inspired by the Orion constellation, which is detected by multiple tools, from photocopiers to image editors.
If you place a 10-euro bill in a photocopier, you'll most likely get an error message. If you try to modify the image of a £5 banknote, some editors may not take kindly to the idea (you can edit, but not print). What exactly is happening? A photocopy or a JPEG file are too crude, but this behavior is nothing more than a preventive measure. The concept of counterfeiting is as old as money itself (mainly metal and paper), but in the 21st century, technology is dynamic, accessible, and easy to use. In an attempt to keep the "enthusiasts" of fake money in check, different ideas were implemented, and one of them is the EURion constellation.
The EURion Constellation
The scientist Markus Guenther Kuhn from the University of Cambridge discovered and named the EURion constellation in 2002, after conducting several experiments with a color Xerox photocopier that refused to process banknotes. It is a small pattern with green, orange, or yellow circles, positioned in a way that reminds us of the Orion constellation, especially its belt. The aforementioned 10-euro bill is one of those that most repeats this pattern, although the EURion constellation is not an exclusive resource of the euro. The Chilean peso, the Mexican peso, Canadian, Australian, and US dollars, the pound sterling, the Swedish krona, and even the Japanese yen have variants of the constellation.
Now, we wish good luck to anyone who tries to obtain detailed technical information about the detection method. Nobody wants to talk about EURión, and some banks have simply come to deny its existence. The most solid data about its origin (an official publication from the Reserve Bank of India in 2005) leads us to Japan, and both the pattern itself and the algorithm would have been created by the Omron corporation (better known for its switches in mice and mechanical keyboards), while its first application dates back to 1996, before the euro entered circulation.
Source: BBC
