Computer printers have been quietly embedding tracking codes in documents for decades

In 2004, when color printers were still somewhat novel, PCWorld magazine published an article headlined: “Government Uses Color Laser Printer Technology to Track Documents.”

It was one of the first news reports on a quiet practice that had been going on for 20 years. It revealed that color printers embed in printed documents coded patterns that contain the printer’s serial number, and the date and time the documents were printed. The patterns are made up of dots, less than a millimeter in diameter and a shade of yellow that, when placed on a white background, cannot be detected by the naked eye.
Continue reading Computer printers have been quietly embedding tracking codes in documents for decades