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 so that this style of perforation can often be identified in any vertical pair of stamps. However, it has never come to our attention that these variations in the placement of the comb have received any important consideration among collectors. Usually the punches, or prongs, that make the perforations are round in shape. They need not be, however, and sometimes they are oblong, or lozenge, in shape or perhaps some other shape. Collectors refer to these odd shapes as "hyphen hole" perfs., or "Lozenge" perfs., and "square" perfs.

Different Types Of Perforations
Different Types Of Perforations

Modern perforating machines, as used in the production of United States stamps, are sprocket wheel punches which punch continuous rows of holes between the stamps. When the stamps are produced on rotary presses in a continuous strip, the sprockets are small wheels that make a continuous row of perforations in one direction. Then, a little further along on the machine, the sprockets are on a long shaft running the complete width of the sheet to produce the cross row of perforations at each turn of the wheel. Naturally this is a complicated device requiring careful coordination with the printed stamps so that the rows of holes will fall at exactly the correct place between the stamps. Nowadays this coordination is accomplished electrically by what collectors call the "electric eye".

eye perforator
Photo by Bureau of Engraving and Printing - Electric eye perforator.

All true perforations actually remove some of the paper and leave holes. (Incidentally, these tiny pieces of paper that are removed from the stamps produced in the Bureau of Engraving and Printing in Washington, D. C, amount to many tons of waste a year and are sold as such at a good profit to the Government.) When no paper is actually removed, but, instead, slits or pricks in the paper are made, they are referred to by collectors as "roulettes." Roulettes are made in a variety of shapes running from plain slits to arcs and serpentine shapes. All have names to collectors and all are easily identifiable as the names describe the shapes. Roulettes may be measured the same as perforations.