Hi Michael,
I used the 'Srail' method (named after one of our community members , Ken Srail). Working with a good scan (does not work with camera images), I took the bottom perfs and digitally compared them (copied and pasted)against the sides and top perfs. Since we know that C2 is perf 11 on all sides, the perfs should lined up quite well. As shown above, at each 'A' location the perf holes are lined up. But as we move towards the 'B' locations the perf holes are not lining up correctly.
There are also other things to look for including the 'sharpness' of the perf hole cut (typically perf holes have a slight ragged appearance and are not perfectly clean cut) , slight pressure ridges (as seen from back of stamp) in the pin direction, and perf holes which are not perfectly round legitimate perfs holes are typically a bit oblong).
Turning to your stock-book can also help. Used as a reference, you can build your knowledge and experience for these kinds of details.
Each of these are pieces of the overall puzzle.
Don
Posted 10/17/2018 10:43 am
