США # 581/596 (Perforation 10x10)

Thank You.… .Look at Scott 552...?
What can be said about this brand. Perforation 11
Make a professional inspection with comment.

This brand has a size of (19#1093;22) so it's a common brand Scott552 perforation 11. I would like to return to mark skott581 once again and clarify one point....
erilaz writes, some stamps printed on the rotary press, which were supposed to be put through a perf. 10 perforator to produce Scott #581, were mistakenly put through a perf. 11 perforator, which produced the error that has Scott #596.
When the Scott 581 catalog perf 10 has a size (19x22,5+) and my brand Size (19.15 × 22.6) in this case, it may not have for example (Scott 581A) and even if the size is width (19.25) and the rerforation 10 it will always be Scott581...?

A catalog number is attributed to a stamp based on all characteristics:
year of issue, design type, color, printing method, paper type and perforations.
So, a stamp with 10 perfs will have a different catalog number than the very same stamp with 11 perfs.
In your case, even if the stamp was printed on the very same machine and on the very same day as the 596, because of being perforated 10 instead of perf 11, it will be cataloged as #581.
To explain it even crazier: if the same sheet of freshly printed stamps would be cut apart in two smaller sheets and one would be perforated 10 and the other would be perforated 11, you would still end with two different catalog numbers.

Thank you very much for the information....

Look at my observations....
Scott552\596...?

Width why 19.15
the height of the preserved 22.00
when the Size needs to be 19x22,5+...?

You don't have to do any measurements at these 1c stamps. First you have to check the perforation, only if it's perf 11 it's theoretically possible that it's 594 or 596. Then the next step is to check the back of the stamp if there is (no) color spots (no spots at all = rotary is possible). Then you can compare the size to another 1c design of same perforation.

Perf # 11

see here :)
https://goscf.com/t/59325&whichpage=2#523386

your stamp with York PA is not perf 11.

which perforation gauge do you use, or do you only look at the horizontal perforation?

To me, something looks strange with the edges of the perforations: too much fiber protruding out of the paper. However soft the paper would be, I wouldn't expect the fiber to break that unevenly.