All modern color printers print a secret, nearly invisible code onto every page to allow governments to track the serial number and timestamps

‘Printer steganography is a type of steganography – “hiding data within data” where tiny yellow dots are added to each page. The dots are barely visible and contain encoded printer serial numbers and timestamps. Unlike many forms of steganography, the hidden information is not intended to be available from a computer file, but to allow serial number and time of printing to be determined by close examination of a printout.
The Electronic Frontier Foundation stated in 2015 that “the documents that we previously received through a (Freedom of Information Request) suggested that all major manufacturers of color laser printers entered a secret agreement with governments to ensure that the output of those printers is forensically traceable….it is probably safest to assume that all modern color laser printers do include some form of tracking information that associates documents with the printer’s serial number.”‘
Read more: All modern color printers print a secret, nearly invisible code onto every page to allow governments to track the serial number and timestamps