The invention of the stamp is lost in history, but in 1840, Mr Roland Hill introduced them to the Royal Mail as a means to show prepayment of fees. The counterman had a large sheet, and with a pair of scissors cut them off as needed. If scissors weren’t available, then a knife. While most of us learned to cut on the line, others slept through that class. Scissors and other cutting instruments weren’t always sharp, so we ended up with uneven cuts. (Figure 1). Mr. Henry Archer invented a machine that punched small holes, which we call perforations, to aid in separation. This was first used on the Penny Red of 1854. The size of the holes, and the number varied. Printers learned that a few large holes didn’t always separate evenly, and many small holes would separate too readily. A Frenchman, Dr J.A. Legrand was able to quantify this property by counting the number of holes in 2 centimeters. That method stuck, and so we identify perforations by counting the number of holes in 2 cm.
Counting small holes is tedious and subject to error, especially if there is a fractional value. Perforations are an important factor in identifying stamps. The protocol for measuring perforations is the top horizon first followed by the right vertical. It’s possible to have a stamp with four different perforations. A number of different tools are available to make this easier.
The gauge with raised holes is basic. This gauge has markings on the edge so you can get a reading without removing the stamp from the cover. (Figure 3). An ingenious inventor put the line on a rotating wheel and added a magnifier and light . (Figure 4). Many other styles exist.
Of course, some people don’t play by the same rules. Some countries that use other fractional values. The continuous line gauge, shown here as the Linn’s Multigauge, gives continuous readings by sliding the stamp along the clear acetate gauge until all the lines match the perforations. (Figure 5).
The One Pound Irish architecture definitive stamp of the 1980’s is perforated 15×14½. (Figure 6). The forged £1 stamp of 1984 can be easily identified, since among other identifiers, it is perforated 15×15. Apparently, the forgers didn’t do their homework.
The measurement of perforations, like many other things, has been automated, and a machine exists to handle large volumes of stamps (at a substantial cost). (Figure 7).
It may surprise you to know the Regional Machin stamps of Northern Ireland, while listed in catalogs as 15×14, are really 14¾ x 13¾. (Figure 8). Why? This unusual size makes it harder to forge. Speaking of the regional stamps, another security item first appeared in 1997 – the large elliptical perf (Figure 9). These are known as syncopated perforations. Special equipment is needed to produce them, thus hopefully discouraging forgery. And still, more, not all the holes are just elliptical – some have the sides parallel rather than a true ellipse. (Figure 9) Some countries have used perforating machinery which give distinctly shaped cuts.
Irish stamps have used a variety of perforations, depending which company or agency printed them. One of the more unusual are some the 1d coil of 1933-34 which have only one hole in the upper right cut side, This wasn’t for separating but rather to align the cutting the horizontally perforated sheet to make coils.
Perforating creates a problem. All those little chads! A chad is the name for the small circle of paper that should be punched out by the perforating pin. Most of us can recall the “hanging chad” problem when punched cards were used for ballots. A condition known as a “blind perf” can happen when the pin indents but does not punch the hole entirely. This leaves the circle of uncut paper where the perforation should be. (Figure 10). This is usually caused by dull pins and/or worn dies.
Another way to separate paper is rouletting, or cutting small slices in an orderly manner, thus making it easier to separate the stamps. There is no paper removed, but the paper is weakened so it can be torn on the line. This was used on the O.E.78, also known as the Airmail Etiquette. (Figure 11). Shown here on a Multigauge, the stubs hit alternate lines of perf 14 which makes the reading a perf 7. The rouletting process was invented in 1854.
With the self-adhesive stamps, the need is to cut the stamp itself, but not the backing paper. This precision slicing is called Die Cutting amd can be seen on self-adhesive booklets. These can be measured with difficulty, since some of the lines are flowing rather than having a clear start or stop. (Figure 12)
In the late 70’s, the Swedish PFA introduced a new type high-speed press with a system that ground away paper to create perforations. A similar system was also used by Harrisons Netherlands. The Japanese postal agency has also experimented with a similar system. Most systems operations are rated as proprietary information and not available to the public.
Perforations are useful, not only for using stamps, but also in their identification, since that is often what makes a stamp unique,.