Perforation

Perforation is the row of small holes punched through stamp paper between individual stamps, enabling collectors and postal customers to separate stamps cleanly along a straight edge. Before perforated stamps existed, scissors or knives were required to cut stamps apart — a process that was slow, imprecise, and prone to damaging the design. Perforations transformed stamp handling and became so fundamental to philately that their measurement and variety now define entire specialties of the hobby.

History

The credit for introducing perforations to postage stamps belongs to Henry Archer, a Scottish-Irish inventor who patented a rouletting (pre-cutting) machine in 1848 and later developed a true perforation machine. After demonstrating its use to postal authorities, Archer sold his patent to the British Post Office in 1853 for £4,000. The first British stamps with machine perforations appeared in 1854, applied to the existing Penny Red imperforate issue. The innovation spread rapidly: the United States adopted perforations in 1857, and most major postal administrations followed within the following decade.

Types of Perforation

Line perforation is the oldest method. A single row of pins punches holes across the full width of the sheet, and the sheet is then fed through again at a right angle. Because two passes are made independently, the holes at the corners rarely align precisely, leaving a slightly ragged corner look. Line-perforated stamps are identified by misaligned corner holes.

Comb perforation uses a comb-shaped die that punches three sides of an entire row of stamps simultaneously — the top and both vertical sides — in a single stroke. The machine then advances one row and repeats. Corners align cleanly, making comb-perforated stamps easier to identify: the corner holes are always perfectly square.

Harrow perforation punches all holes across the entire sheet (or a large section of it) in one impression. This method was less common historically but produces the most consistent results. The term is sometimes used loosely to describe comb perforations applied across a full sheet.

Syncopated and interrupted perforations are specialised variants where holes are omitted at intervals to make stamps harder to counterfeit or to facilitate automated handling. Australian issues of the 1990s and 2000s used syncopated perforations extensively.

Measuring Perforations

Perforations are measured with a Perforation Gauge, a tool that counts the number of holes (or teeth) per two centimetres. A stamp described as “perf 14” has 14 holes per 2 cm along that edge. Stamps can have different gauges on different sides — these are called compound perforations and are written with the horizontal measurement first (e.g. “perf 14 × 13½”).

Why Perforations Matter for Collectors

Many classic stamps were issued with multiple perforation gauges at different times, and the different perf varieties can vary enormously in catalogue value. The 1857–61 US one-cent Franklin, for example, exists in perf 15, perf 15½, and other gauges, each with a different market value. The same stamp design with an apparently minor difference in perforation can separate a common variety from a major rarity.

Perforation quality — the evenness of the holes and the centering of the design within the perforated margins — is one of the key factors used when grading stamps. “OP” (original perfs) versus a stamp that has been reperfed (given false perforations to improve its appearance) is a serious authenticity concern for expensive classics, and expertisation certificates from bodies such as the Royal Philatelic Society London (RPSL) or the Philatelic Foundation routinely comment on perforation integrity.

Coil stamps and se-tenant pairs present their own perforation considerations: coil stamps typically have straight edges on two sides, while se-tenants must be kept joined to preserve their value and the integrity of their perforations.