November 7th, 2005
Color Printer Watermarking
The EFF has broken the tracking code for the Xerox DocuColor. The DocuColor prints a faint 15×8 grid of yellow dots on every page. To see these dots you need a magnifying glass. You can also use a blue light to make the dots appear black. The EFF page has a built in application for decoding the dots which hide the time, date, and serial number of the printer. The EFF also maintains a list of printers which do or don’t have this “feature”.