https://hackingpassion.com/categories/privacy/Recent content in Privacy on HackingPassion.com : root@HackingPassion.com-[~]HugoenThu, 08 Oct 2026 11:26:20 +0200https://hackingpassion.com/printer-tracking-dots-serial-number/Thu, 08 Oct 2026 11:26:20 +0200https://hackingpassion.com/printer-tracking-dots-serial-number/<p><strong>Your color laser printer puts its serial number on your pages in yellow dots.</strong> You will not notice them. Printers from <strong>15 of 18 makers</strong> had them, a Secret Service request going back to at least the early 1990s.</p> <p>A color laser printer works with four toners: cyan, magenta, yellow and black. Next to the text and the pictures you asked for, many of these printers add something you never asked for, in yellow. Tiny dots, spread over the white parts of the paper in a fixed pattern. On white paper, a few specks of yellow are almost impossible to see with the naked eye. Shine a blue light on the page and look through a magnifying glass, and they show up black.</p>