(Repost from last bread 🥖 for eyes on)
Not an INK fag.
I was told about a medical malpractice case—back in the day when pens were used. The medical record was altered, this was discovered by analysis of the ink (different lot numbers).
I wonder how many mail in ballots have the same ink?
Statistical impossibility
https://archives.fbi.gov/archives/news/stories/2005/july/ink070505
A Matter of Ink Evidence
That's good news for investigators of insurance fraud, currency counterfeiting, tax evasion, and insider trading violations. Just consider a recent case involving the ink of a particular entry on a stock worksheet that was tested against the rest of the document's ink. Differences in the samples suggested that the questioned entry was made on a separate occasion, possibly to cover insider trading violations.
A process called thin-layer chromatography (TLC) is normally used
Also
Capillary electrophoresis (CE) has recently been used for ink analysis. A minute volume of ink (nanoliters) is injected in a narrow silica capillary filled with a buffer solution. Electrical current is then applied to the capillary to separate the ink into its components. Each component passes a photodiode array detector, which records an ultraviolet-visible spectrum. The process is automated, fast, and results can be stored electronically allowing the development of a searchable reference library. This process also detects non-dye additives in the ink that potentially can be used as identifiers.