I have read in several places how KGB kept track of each typewriter in the USSR. A sample page was typed on each typewriter and handed to the KGB for storage. Later on this page would be referenced in order to track down the origin of a certain suspicious document.
My guess is there must have been hundreds of thousands of these typewriters across USSR.
I was wondering how did the KGB perform the mammoth task of comparing a certain document with these sample pages? Did they use any tricks, how did they organize their work etc...
Sources:
https://en.wikipedia.org/wiki/Typewriter#Forensic_examination https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/fall_winter_2001/article05.html (Section "Nightmare for the KGB: The Advent of Photocopy Machines ")
I suspect you may be making wrong assumptions. There are generally two types of document analysis you can make:
““Identification” of a typewriter make and model comprises a determination of the manufacturer’s name or trade-mark, and the particular model used. Such a determination is sometimes called “group identification” or “system identification”. In this class of problems, the document examiner studies only the questioned document, or documents, under question, without comparing them with documents of known origin.”
That would be the type of examination you could do for documents of completely unknown origin, altho it's usefulness in that scenario would be rather dubious. You would be limited to determining the model of the typewriter, if that was even possible. Consider that this was such a difficult problem there were a bunch of competing classification systems in the west, and even then they didn’t claim they could identify the brand of a typewriter with certainty in all cases. This may or may not have been easier in the USSR, but I suspect they ran into similar problems.
The other type of identification is just a comparison. Treat this like finger print comparisons before the information age. Slow, labor intensive, requiring significant expertise, and, unlike fingerprints, typewriters change with use and time. So, this would only be done once you have narrowed down the list of suspects to hopefully single digits by using more traditional means like location, interviews, etc. Now that we have dispelled the notion of a bunch of clerks comparing millions of pages to a sample in a central library, we could explore different means, but investigation is generally ad hoc.