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How to Identify Stamp Perforations

Perforations are the small indentations that run around the edges of a postage stamp. They were originally introduced in the 1850s to make stamps easier to separate from each other -- the early ones had to be laboriously cut from printed sheets with a pair of scissors. The spacing of these perforations differs depending on which perforating machine is used. Within a two centimeter area, there can be as few as seven and as many as 18 perforations. This is a stamp's "perforation number," which you will see referred to in guides as "perf 7" and so forth. Philatelists like to identify perforation numbers because they are a subtle way of spotting different issues of otherwise identical stamps. To do this they use special gauges.

Things You'll Need

Perforation gauge

Instructions

- 1
  Buy a perforation gauge either from a stamp dealer or an online philatelic accessories store. They come in two varieties. One is a length of transparent plastic with black lines running longitudinally. The other is a card with silhouettes of various perforation profiles printed on its surface.
- 2
  Use the plastic gauge in this way. Lower the ruler on top of the stamp and move it up or down until the black lines -- which slant slightly -- fall exactly into place with the points of the paper "teeth" to either side of each perforation. Once you have done this, look to the side of the gauge where you will find the stamp's perforation number.
- 3
  Use the card gauge in this way. Place the stamp on top of the card, then move it from silhouette to silhouette until you find one that exactly matches the shape and size of the stamp's perforations. Each silhouette will have an accompanying perforation number.

Stamp Collecting