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The following article appeared in the March 2005 issue of the Canadian Paper Money Society Newsletter. It is an original work of the author, Brent W.J. Mackie. All rights reserved. © Copyright 2004, 2005 Brent W.J. Mackie.

Eurion Constellations

By: Brent W.J. Mackie

What is common among the following banknotes?

  • Canadian Journey Series 2000-2004 $5, $10, $20, $50, $100
  • United States of America Series 2004 $20, $50
  • France 1997 100F
  • Euro €5, €10, €20, €50, €100, €200, €500
  • Romania 1999 Polymer 2,000 Lei
  • Germany DM50
  • Bank of England 2000 £5, £10, £20

Obviously they are all legal tender in their own countries, and they are pieces of paper or plastic (polymer) that have some value. But that is not what I am driving at.

In 2002, while Cambridge University lecturer Dr. Markus Kuhn was experimenting with a €10 note and a new Xerox colour photocopier, it was discovered that a certain pattern of yellow, orange or red circles was causing the banknote to be rejected by the copier. Refer to Figure 1 for this pattern.

Figure 1

Figure 1: This pattern of five circles has been determined to cause new Xerox colour photocopiers to refuse to make copies of documents containing the pattern

These patterns appear most distinctly when viewing only the blue channel of the colours of the banknote. This can easily be achieved using any sophisticated graphics editor such as Adobe Photoshop. Without going into great detail about how channels work, allow me to say that viewing only the blue channel produces a grayscale image that appears more white in areas of a high blue concentration, and much darker in areas with very little blue. Yellow ink contains little or no blue, and so appears quite dark when the blue channel is viewed. This makes it very easy to view the patterns. All of the following scans consist solely of the blue channel to enhance the visibility of the patterns.

Dr. Kuhn has named these patterns "Eurion Constellations" since they were first discovered on Euro banknotes. Refer Figure 2 for an image of a €10 banknote with the Eurion Constellations clearly identified.

Figure 2

Figure 2: €10 banknote with Eurion Constellations identified by black lines connecting the circles

These same patterns were also found on several other banknotes including each denomination of the Euro, and several recent issues from England, Germany and elsewhere. My own investigation has uncovered these patterns on all of the above-mentioned banknotes including the latest Canadian and American banknotes. The earliest known banknote to feature this constellation is the French 1997 100F banknote, although the most recent DM50 banknote from Germany also features the constellations. I do not know the issue date of this note.

As mentioned, each of the Canadian Journey Series banknotes feature these Eurion constellations on the front and back of the note. On the front, they typically appear between the shoulder of the Queen or prime minister and run along in a band to the signature area. There are also some constellations scattered in the building. The only exception is on the new $50, where no constellations appear on the front except in the horizontal band. Refer to Figures 3 and 4 for scans of the Journey Series $50 and $100. The patterns are indicated by black lines connecting the five circles.

Figure 3

Figure 3: Canadian Journey Series $50 banknote

Notice that in the $100 banknote below, there are several Eurion constellations hidden in the building, but in the $50 banknote above, only the horizontal band contains any complete constellations.

Figure 4

Figure 4: Canadian Journey Series $100 banknote

These Eurion Constellations are also featured on the reverse of the Canadian Journey Series banknotes. They are clearly identifiable on the $20 and $100 because they are enclosed in large blank circles. The $5 and $10 simply use yellow Eurion Constellations without the enclosing blank circles, making them slightly harder to see, but still very visible. The $50 banknote hides the yellow circles by a red fine line pattern. They are nearly invisible to the naked eye, but show up clearly when viewing only the blue channel in Photoshop. Refer to Figures 5 and 6 for scans of the reverses of the $50 banknote, first just as a plain conversion to grayscale, then viewing only the blue channel.

Figure 5

Figure 5: Canadian Journey Series $50 banknote, all colours

Figure 6

Figure 6: Canadian Journey Series $50 banknote, blue channel only

The Eurion constellation also appears on American banknotes, specifically the newly-redesigned Series 2004 $20 and $50 banknotes. Our American friends at the Bureau of Engraving and Printing exercised some rarely-seen creativity with their currency and not only added a splash of colour to the new notes, but also disguised the Eurion Constellations as small "20"s and "50"s scattered around the open areas of the buildings on the back of the notes. Refer to Figure 7 for a scan of the newest $50 banknote from the United States.

Figure 7

Figure 7: United States of America, $50 Series 2004 Banknote

The British also use the Eurion Constellation on their banknotes. The £20 note even disguises the patterns as musical notes on one side of the note. France has disguised the Eurion Constellations as well, composing them of the zeroes in several lines of repeated "1 0 0 F" text in a corner of the 100 F French banknote.

The Eurion Constellation is known to cause new colour photocopiers to refuse to produce a copy and it was surmised that the same pattern of circles was what was causing the newest version of Adobe Photoshop to refuse to open or process some images of banknotes. This was quickly discovered not to be the case, and obviously Photoshop was picking up on something else in the image.

The Eurion Constellation currently appears on the banknotes of Canada, Europe, England, the United States, France, Germany, Romania and potentially other countries around the world. Especially when one considers the new Rules for Use website (, it is obvious that the central banks of many various countries are working together to prevent counterfeiting of their respective currencies.

Over the years, various security features on banknotes including infrared ink and now the Eurion Constellations have been discovered. This begs the question about what else is hidden in our banknotes that we don't know about yet?


Dr. Markus Kuhn's website (
Wikiverse (
Euronize Tool ( Article (
Freedom To Tinker (