You learn something here almost every day!! I've heard of the two types of perfs but never seen an explanation before. Do you always get the same type of "mess" where the lines of perforations meet? If so then that could show up at the corners of single stamps and sort of explains why many stamps have slightly rounded corners and some don't. Good to know, thanks!!
Yes, the line perfs (also known as comb perfs) are done separately. The sheet is perforated horizontally then vertically so it is very unlikely that they would look like bullseye perfs between the stamps. Actually, don't quote me on the order h/v or v/h but you get the idea. The bullseye perf is done in one step.
I am picturing a pair of plate blocks that help with identification of the stamps.
The stamp on the left is Scott 2524 and the one on the Right is Scott 2524A.
2524 is Line Perforated (11) which means that the perforations go through the selvedge to the end of the paper in the selvedge and the point where the 4 stamps meet there is usually overlap.
The stamp on the left is Scott 2524A (13 x 12 3/4). This one is Bullseye Perforated. You will notice that the perforations do not go all the way to the edge of the paper in the selvedge and the point where the 4 stamps meet is just a perfect hole.
Scott 2524 PB is valued in the 2020 Durland Plate Block Catalog at $2.75 and Scott 2524A is valued at $50. I initially thought that these were both 2524 until I noticed the difference in the perforations without even needing a perforation gauge. Of course the Durland Catalog would have let me know that Plate U3342 was not Scott 2524 as that stamp was not issued with that plate.
Bob
re: A Reason to Save Selvedge for Identification
You learn something here almost every day!! I've heard of the two types of perfs but never seen an explanation before. Do you always get the same type of "mess" where the lines of perforations meet? If so then that could show up at the corners of single stamps and sort of explains why many stamps have slightly rounded corners and some don't. Good to know, thanks!!
re: A Reason to Save Selvedge for Identification
Yes, the line perfs (also known as comb perfs) are done separately. The sheet is perforated horizontally then vertically so it is very unlikely that they would look like bullseye perfs between the stamps. Actually, don't quote me on the order h/v or v/h but you get the idea. The bullseye perf is done in one step.