Postage stamp separation

Methods of separation include: In the early years, from 1840 until 1850, all stamps were issued imperforate, and had to be cut from the sheet with scissors or knife.

This machine consisted of lancet-shaped blades working on a fly-press principle and piercing the paper with a series of cuts.

Archer then abandoned this approach in favour of perforation, a process which used rows of small round pins to punch out the holes.

The standard for describing perforation is the number of holes (or the "teeth" or perfs of an individual stamp) in a 2-centimeter span.

Stamps that are perforated on one pair of opposite sides and imperforate on the other have most often been produced in coils instead of sheets, but they can sometimes come from booklet panes.

In the 1990s, Great Britain began adding large elliptical holes to the perforations on each side, as an anti-counterfeiting measure.

It was used by a number of countries, but was rarely if ever seen on modern stamps until the die-cut serpentine roulette self-adhesive varieties appeared.

[5] Because self-adhesive stamps contain a sticky layer, it is far easier to roulette the separations, than to actually punch out the holes for perforations.

These are inevitably diecut, meaning that the stamps themselves are cut entirely apart, held together only by the backing paper.

From 2012 to 2016 the United States also sold small numbers of the stamps issued during this period in sheets without die cuts, thus creating imperforated varieties of them.

Occasionally pairs or larger groups of stamps may be imperforate between meaning that they are not separated on all sides.