posted 05-10-2013 03:09 AM
The autopen machine could use any pen of the operator's choice — and the pens could be changed between the signatures being added to the same item (since the machine only traced one pattern at a time).
So pen type cannot be used to discern autopens from autographs.
The best way to determine an autopen is to compare the style of the autograph against the known patterns. Fortunately, there are several websites that provide examples of these patterns, including Chris Spain's Astronaut Autopen Guide.
There are other indicators that can be used to suggest the use of an autopen, including a shaky signature or ink dots at the end of trailing lines, but those are less definitive than comparing with the patterns.
But keep in mind, the autopen was a mechanical, hand-fed device, such that the shape of the signature applied could be affected by the machine being shook, or the item being signed being pulled through more slowly or quickly. So, don't look for an exact match to the pattern (though those exist) but a general match to the style of the autopen signatures.