509A (Perf. 10 At Top) With Irregular Perforation Holes

hello,

I just looked at the PDF of the current 1192 sale at Siegel which is very interesting. But I wonder at some of the perf 10 (top or bottom) stamps, why the perforation looks so wrong. As I am not an expert, for me this stamp for example looks reperforated - why isn't it? Were those perf 10 perforation rows often not regular but crude?

and if it's genuine, how should I ever know if a similar stamp is genuine when the perforation looks like that? (I learned a lot here about the genuine perforations which I can't use in this case)

(image of Siegel)

Looks OK to me. It has a 2008 PF cert.

The top perfs look strange because because this is a transitional stamp ... perf 11 on the left & perf 10 on the right.

thank you. indeed there was a transitional perforation, but if you look at the distance of the two holes on the left, it's just like the perf 10 holes on the right. but not only the perforation gauge, the whole perforation just looks very strange to me, and not only in this case, in other cases, too:
https://siegelauctions.com/sale/1192/lot/614
https://siegelauctions.com/sale/1192/lot/548
https://siegelauctions.com/sale/1192/lot/557
https://siegelauctions.com/sale/1192/lot/569
https://siegelauctions.com/sale/1192/lot/572

some of them, like lot 548 and 569 don't really look "perforated", more like rouletted :). So what does tell somebody writing a certificate for such a stamp that the perforation is genuine?

These were WWI era stamps, so replacing perforating pins was not likely to be very important. And the paper for these is very soft as well. The combination made for rather ratty looking perfs.

thank you - yes this is the explanation for the result.

but how can you say that this result is genuine then?

I can't see how existence and direction of paper fibres, indentations at the hole edges and the general shape of the holes can be proven in such cases? Is there any hidden hint?

Knowing how they were produced and looking for the signs that result, such as pressure ridges. Also direct comparisons with other examples. Fake perfs are never produced the way genuine ones are, and the differences can be seen from the back of the stamp in question.

The 19 or so perforations in the perf 10 row have a distinct pattern and alignment relative to the normal perf 11 row on either side of the transition. The offsets and odd spacing appear to be consistent with this image from the PF database:

http://pfsearch.org/pfsearch/images/478/478705.jpg

or this:


http://pfsearch.org/pfsearch/images/446/446197.jpg

thank you both very much, great to have that knowledge. With the pressure ridges and the perforation pattern shown in the two PF examples there are indeed two important characteristics you can use to examine such a perforation 10 at top or bottom. I didn't actually know that all of those stamps should show the same pattern so came from the same perforation pins. I guess this is true for the 1917 issue, and also for the 1922-23 issue, short for all those perf 10 error stamps, as both were perforated with this happening in the 19th row in 1923?

(still I wonder a little bit about why in my links the perforation holes themselves have such a strange shape while in the two PF sheet example the holes are just normal holes)