|
Perforations and Perforation Gauges on Postage Stamps
Henry Archer constructed the first perforating machine in 1847, but the first perforated postage stamps were not issued in England until 1854. The perforations on stamps vary quite significantly. In some cases, the perforations are small and close together whereas on other stamps, they are larger with wider spaces between them. To make the differentiation of perforations possible, the dimension of twenty millimeters was introduced as an international philatelic unit. If a stamp is described as ‘perforated 12’, it means that exactly 12 perforations fit into the twenty millimeters. Perforations can be measured up to a quarter of a perforation. If a stamps is described with two figures for the perforations, the first number always refers to the horizontal perforation and the second figure is for the vertical.
As the technique of perforations developed, different types of perforations were distinguished. The single line perforation refers to a long line of regularly spaced needles. Each horizontal line is punched, then the sheet of stamps is turned for the punching of the vertical lines. Because this process involved human labour, sometimes the sheets were not placed exactly and this impacted on the distance from the stamp to the perforation line or resulted in a slight lean in the perforations. When the worker handling the sheets on the perforating machines was careless and the horizontal or vertical perforation was slightly displaced, off-centre stamps were produced.
With an increase in knowledge and industry, comb perforating machines were introduced. These machines allowed the top row of horizontal perforations and all the vertical perforations for one row of stamps on a sheet to be punched simultaneously. This process, however, still allowed for human error as the sheets were moved from one row to the next and, frequently, perforations in the corners were irregular. Because of this imperfection, the harrow perforating machine emerged. It allowed for a complete sheet of stamps to be punched in a single process. With this machine, all stamp corners were absolutely identical.
Coil and stamp booklet perforating machines developed later. The perforations of coils length-wise was unnecessary, and so only the perforations across the coils were left. Most coil stamps can be easily recognized as they are perforated on two sides only. This was not a universal practice and Great Britain and Germany issued coil stamps perforated on all four sides. In the Netherlands, a special type of perforation was introduced for coil stamps. To ensure that stamps did not tear easily in the perforating machine, several perforating pins were removed and interrupted perforations resulted. Some Dutch stamps were also issued in sheet form with interrupted perforations and this was known as syncopated perforation.
Some Swedish stamps can be found with normal perforations (on all four sides), coil perforations (on two sides only) or perforated on three sides. The last mentioned come from stamp booklets and this form of perforation for stamp booklets was adopted by several other countries.
|
