Interesting. I remember reading a news article before 2017 stating that printers used to do this, but the practice has since ended because someone was able to prove they were doing it in the mid-2000s. At the time, I saw some people on Reddit claiming they just switched to a new, harder to detect method, and everyone was saying they were conspiracy theorists.
On wikipedia there's some suggestion that methods that involve intensity of toner/ink across a document could be used to uniquely identify a machine but no such methods are currently publicly known (at least as far as the Wikipedia article has been updated)
Interesting. I remember reading a news article before 2017 stating that printers used to do this, but the practice has since ended because someone was able to prove they were doing it in the mid-2000s. At the time, I saw some people on Reddit claiming they just switched to a new, harder to detect method, and everyone was saying they were conspiracy theorists.
On wikipedia there's some suggestion that methods that involve intensity of toner/ink across a document could be used to uniquely identify a machine but no such methods are currently publicly known (at least as far as the Wikipedia article has been updated)
Digimarc
Source: I work in flexography.