Last time we tested similar MFP systems, we found that they adhered to federal anti-counterfeiting guidelines that recommended overlaying all color jobs with the machine’s serial number, encoded in big yellow dots. The dots were almost invisible, but not quite.

This time, the yellow dots were no longer apparent. Turns out they’re still around, but the invisibility factor is greatly improved -- at least one vendor says its machines still print the yellow dots, albeit much smaller. (See our printer round-up, “Color MFPs go mainstream.”)

Other protective measures include identifying currency colors to prevent their exact replication and recognizing specific currencies or other documents based on image profiles, as in Xerox’s Anti-Counterfeit Detection technology.

Another vendor told me that its anti-counterfeiting measures detect repeated attempts to make illegal copies and freeze the machine; only a site visit by a company rep can unfreeze the system. That scheme puts a big burden on the machine’s smarts to distinguish legitimate from illegal copying, however. In fact, my test system warned me that it was about to freeze on a counterfeit job when I was simply copying its own configuration report.

Of course, many anti-counterfeiting measures may never be known, in the interest of keeping those secrets out of criminals’ hands. That inherent secrecy caught the eye of the Electronic Frontier Foundation (EFF), which has concerns about some of the anti-counterfeiting measures and the practice of printing encoded information -- including those aforementioned yellow dots -- onto documents to identify the printer that created them.