Don't ask how much time I spent on this. It would just be embarrassing for all concerned.

Some time ago, it came out that Adobe's newest version of Photoshop, like a number of colour photocopiers, contained anti-counterfeiting measures that would recognise a banknote when scanned in. The intention was to prevent people from using Photoshop for home counterfeiting; even assuming that your average home counterfeiter would be slowed down by not being able to use Photoshop (the GIMP isn't exactly difficult to get hold of), the integration of the countermeasures into the software was incredibly poor. Within a very short space of time, people found workarounds that were as simple as scanning into a different program and copying into Photoshop.

Even if the technology wasn't very impressive in execution, I have to admit it's pretty clever to recognise banknotes from so many different countries (it works with recent pound notes, all euros, all dollars, and a bunch of others), and it apparently does it fairly simply. All it has to do (in the case of photocopiers, anyway - apparently the Photoshop algorithm is somewhat more complicated) is recognise a small pattern of yellow circles that currency makers around the world have agreed to insert into their notes.

To see what I mean, take one of the new Adam Smith £20 notes and look just above the reversed £-sign on the Smith side. The circles are on the Queen's side of the note too, parallel with the hologram strip all the way down. It's not difficult to find them on a number of other notes, too (they're in the watermark on a £10, for instance).

This is all well and good (even if it's not very effective) - problems might come, though, because being flagged by Photoshop might be taken as an indication that the note is genuine. And if that's the case, all one needs to do is insert the circles into one's own designs. Now, I don't think that's very likely, but given my tendency to go overboard with these things, I have done precisely that.

Click the image for a big version. I'd be very interested to know whether any of you with Photoshop CS1 or later, or a colour photocopier, are unable to open or print this...