Mechanical typewriters have their own form of watermarking, albeit unintentionally. Slight differences in manufacturing and wear introduces measurable differences into the typewritten page.
It's how the FBI was able to link the Unabomber's "manifesto" to one of the typewriters found in his cabin:
Mechanical typewriters have their own form of watermarking, albeit unintentionally. Slight differences in manufacturing and wear introduces measurable differences into the typewritten page.
It's how the FBI was able to link the Unabomber's "manifesto" to one of the typewriters found in his cabin:
https://archives.fbi.gov/archives/about-us/lab/forensic-science-communications/fsc/april2001/held.htm