As many of you know, modern color copiers/Photoshop detect currency and refuse to scan/open such images. There has been some work in reverse-engineering what algorithms are used to determine what is currency. I am very much interested in expanding this work towards the end of creating false positives. [Think like a T-shirt that when worn would make you difficult to photograph, or artists discreetly embedding such watermarks inside photos that they dont want photoshopp'ed, etc.]

Consider this a call for any comments/knowledge relating to this issue.

Also see: http://www.wildspark.com/eurionize/
http://www.freedom-to-tinker.com/archives/000497.html

Photoshop Currency Detection