Do you know how to measure perforations? Do you have a perf gauge? For one thing, don't try counting perforations. The perf gauge measurement is the number of perforations within a distance of 2 cm. The top edge of your stamp is approximately 2 cm wide ... so one could perhaps get an estimate by counting the perforations along that edge. But using a gauge would be better. Many U.S. stamps use the same gauge size in both horizontal & vertical directions. Your stamp would appear to be perf 10 along the top & bottom ... I'm not aware of any compound perf stamps that are perf 10 along the top, so the vertical gauge is also probably 10. You could verify this without a perf gauge by using a "ruler" to verify that the same number of perforations appear along both horizontal & vertical edges within the same fixed distance. Once you know the perf measurements, use the Stamp Smarter guide. Added: Compound perforations occur when the gauge size is different in the horizontal & vertical directions. Common usage is to give the horizontal gauge first, then the vertical. So a 11x10.5 perf stamp is perf 11 along the top & bottom and perf 10.5 along the sides.
thanks to all of you who tried to help me about my problem.this is not a singleone problem but 47 problems,because I own so meny 5 cents stamps.For me they look similary ,some are with watermark(double and single)flatplate.Because i'm not a profesional and filatelist,the only way to lern about stamps in last 10 mounth is internet.Once again thank you for your support.!#10084;#65039;