When the printer consumer market got flooded by an invasion of sharper, faster, cheaper machines a question bubbled in the mind of many: ‘Can I print money with that?’.
To prevent copy and image manipulation of currency is a real nasty problem, counterfeit money is more than ever unrecognisable from real money. Not longer than a month ago I saw and touched six 20 euro banknotes and I could’t feel the difference from real money, the only deficency was the missing stripe in the middle of that piece of paper.
That’s why we have to introduce new designs and form factors in the newer batches, because the bad guys are catching up with the technology and the supply chain. Keeping things movin’ is a way to zeros their knowledge and know how.
But how can you prevent software manipulation of images containg currency? It appears that this problem has already been addressed.
I present you the EURion constellation, a pattern you can find on your banknotes that can be recognised by machines like your scanner.
When this pattern is found in the image the scanner could also refuse to scan your document, making it a good choice to use it as a watermark to prevent copy and distribution of confidential material.
This image shows that under blue/black light the pattern glow making it visible.
Other techniques similar to the previous includes the printer steganography, a way to include informations into a piece of paper at printing time.
Edit 03-04-2015: I found an article about the topic of photoshopping money, it’s on hyperallergic.com