About the tracking dots Most home and office printers add metadata to printed sheets in the form of very tiny yellow dots (sometimes called a machine identification code) that can’t be seen with the naked eye. The layout of the dots are different between printer brands and some don’t leave any at all. Information like serial number and sometime the print time is encoded in these dots. They can act as a “signature” for the printer that law enforcement uses as document forensic evidence (like in...