Stamp Perforations

Stamp Perforations - Part 1
The world's first postage stamps, issued by Great Britain in 1840, were without means of self-separation. They are called "imperforate" or, abbreviated, "imperf." Such stamps had to be cut apart...
Stamp Perforations - Part 2
Stamps in sheets are stacked in quantity and the comb is punched through the top row. Then the comb is moved to the next row and so on. The comb does not always line up exactly with the preceding row...