The EFF Cracks Secret FBI Printer Tracking Codes

Almost all printers secretly print dots without your consent, which are invisible to the naked eye. Apparently Xerox (Docucolor series), and possibly others, have included this technology. This is being used by the FBI to keep an eye on groups such as Greenpeace and United for Peace and Justice. As an effort of their Machine Identification Code Technology project, the EFF has cracked the code, and provided a DocuColor Tracking Dot Decoding Guide for decypherment.

Pure blue light causes the yellow dots to appear..

[HomelessInLaJolla]

...black.

I remember black dots on letter paper from photocopiers when viewed under UV lights or in dark rooms as early as grade school. It's possible they were just imperfections in the paper or specks of dirt but, just as likely, they may have been part of a tracking matrix.

How long do you suppose this has been going on?

Re:

[Jeremiah Cornelius]

The codes I know are introduced with popular color copying - circa 1995. This was supposed to track currency counterfeiters. That doesn't mean there wasn't anything going further back.