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So looking at a document, you'd not be able to know what typewriter it was written from, no. However, looking at a document, you may be able to tell the make a

So looking at a document, you'd not be able to know what typewriter it was written from, no. However, looking at a document, you may be able to tell the make and model of the typewriter, due to different typefaces and known mechanical differences across the make/model. That, coupled with a location or list of suspects, would allow you to examine specific typewriters. You may be able to determine a letter was written from a -given- typewriter, as machining differences in the keys, and differences in wear and tear over time can lead to minute differences in how the ink adheres. If you also have a letter written by a specific suspect, the variation in typing (how hard they hit the keys, common typing mistakes, etc) can lead to greater certainty of the author.

reaperducer 5y ago
So looking at a document, you'd not be able to know what typewriter it was written from, no. Actually, yes. Typewriters, especially well-used ones develop their own quirks. The "e" is a little higher or lower. The "o" gets a little filled with ink. It's mechanical, so parts wear, things get a bit off, and with enough use, each typewriter develops its own fingerprint. It's been a thing in mystery novels at least back to the 1920's.
- LogonType10 5y ago
  How reliable is this compared to bite marks?
- lostcolony 5y ago
  Actually, no. If you were to hand someone a typed document, you would not know "Ah-hah. I can tell by the e that is precisely 3 nanometers above the line, and the slight smudging of the ink on the qs, that this was written by Joe Schmoe's typewriter, which I have "registered", but which I otherwise do not have access to". You say it yourself; typewriters "develop" quirks, in addition to any they start with, meaning that even if you had collected samples of every typewriter at the time of sale, and had a way to compare a document against all of them (despite this being pre-computer, given the prevalence of typewriters), you would not be able to find a match. What -you- are describing, is "Was this particular document written on this particular typewriter", which is possible by comparing it against a document you know to have been written by that typewriter, and which I detail in my answer which you didn't fully read ("That (...) would allow you to examine specific typewriters. You may be able to determine a letter was written from a -given- typewriter"). This is identical to ballistics; finding a fired bullet does not tell you the specific gun that fired it (but may tell you the model/make; certainly, it will tell you the type of ammunition it takes). But if you have a bullet of known provenance (i.e., one you fired from a suspect's gun), you can tell if the markings left on the bullets match.
int_19h 5y ago
Or you could just require a sample page of printed text submitted for every typewriter. Which is exactly what KGB did.

reaperducer 5y ago

So looking at a document, you'd not be able to know what typewriter it was written from, no. Actually, yes. Typewriters, especially well-used ones develop their own quirks. The "e" is a little higher or lower. The "o" gets a little filled with ink. It's mechanical, so parts wear, things get a bit off, and with enough use, each typewriter develops its own fingerprint. It's been a thing in mystery novels at least back to the 1920's.

LogonType10 5y ago
How reliable is this compared to bite marks?
lostcolony 5y ago
Actually, no. If you were to hand someone a typed document, you would not know "Ah-hah. I can tell by the e that is precisely 3 nanometers above the line, and the slight smudging of the ink on the qs, that this was written by Joe Schmoe's typewriter, which I have "registered", but which I otherwise do not have access to". You say it yourself; typewriters "develop" quirks, in addition to any they start with, meaning that even if you had collected samples of every typewriter at the time of sale, and had a way to compare a document against all of them (despite this being pre-computer, given the prevalence of typewriters), you would not be able to find a match. What -you- are describing, is "Was this particular document written on this particular typewriter", which is possible by comparing it against a document you know to have been written by that typewriter, and which I detail in my answer which you didn't fully read ("That (...) would allow you to examine specific typewriters. You may be able to determine a letter was written from a -given- typewriter"). This is identical to ballistics; finding a fired bullet does not tell you the specific gun that fired it (but may tell you the model/make; certainly, it will tell you the type of ammunition it takes). But if you have a bullet of known provenance (i.e., one you fired from a suspect's gun), you can tell if the markings left on the bullets match.

int_19h 5y ago

Or you could just require a sample page of printed text submitted for every typewriter. Which is exactly what KGB did.