Technical Question For A Newbie

Hi. I want to introduce myself as a newbie who would like to discern if I have anything of value. As a perfect newbie test, I have found 2, 1c US Franklin green stamps...lol. So it has boiled down to either 552, 632 or 596. The question I have is about the perfs. I understand how they are measured, however, I am perplexed when looking at the Stiegle Auction pics of 596's...if they are perf 11x11, why do they all have an actual count of 11 holes by 13 holes? I get that the vertical is longer at 22.5mm but the ~3mm difference doesn't account for 2 extra holes...? Someone please explain. Thank you.

I recommend you go over to the USA area where someone might know something about this.

11 is the perforation 'gauge' - there are about 11 holes PER 2 centimeters. Therefore there will be more holes on the sides.

Welcome,
Best way to start is to post images of the front and back of the stamps; this is the most efficient approach.
Don

Thanks everyone. Its really just a technical question about perforations...how can 2 extra holes fit in the space of less than 3 mm...a Perf 11 has 11 holes in 2cm (20mm/11)=1.81mm per hole?? I am perplexed.

The way you are looking at it, doesn't take into account the measurement
is taken from the centre of the puncture, ergo, your first point of measurement, is really half a puncture.
When employing math, one counts the "teeth" over a constant.
Hope that helps.

Some examples... you can count these out - left to right 11x11,11x11,11x10.5,10x10,10x11 - note the first 2 are exact side=top



the second stamp is laying with top at left - hope that is not confusing things. The leftmost stamp is showing 12 holes PLUS 2 half holes, the rightlist is showing 13 holes / they are the same vertically, just depended on there the perfs fell.
ps: nice to see the SCF site has upgraded to 300KB/image !