Perforation

Perforation – A way of making the separation of stamps easier by taking away small pieces of paper from the gutters between the stamps. The size and amount of holes could vary on opposing sides of the stamps and would be determined by the direction of the grain and strength of the paper, fewer or smaller holes being necessary on the weaker edge.

Perforations could be applied either with a flat bed operation or a rotary action and are split into the following sub types:

• Line perforation – where one or two parallel lines in one direction only are perforated with each pass of the perforating machine. To perforate complete sheets the paper has to be turned through ninety degrees and perforated line by line in that direction.
• Comb perforation – where at least three sides of the stamp are perforated with each pass of the machine. The second pass completes the first stamp and perforates three sides of the second stamp.
• Chambon perforation – a kind of comb perforation which perforates one complete stamp and half of two adjacent stamps. Then moves over two stamps and completes the half perforated stamp and half of next. Where the comb register is not exact a thicker or thinner tooth will be left at the centre of each side of the stamp.
• Harrow perforation – where a complete sheet is perforated with one pass of the machine. Sometimes the outer edge of the sheet is left imperf. All over perforation – for use with non-rectangular stamps such as triangular or circular stamps.
• Pin Perforation – a perforation created by sharp pins which don’t remove paper but make a hole rather than a cut.

Perforations are further described firstly by reference to the size of the hole – large or small – and to the effectiveness of the perforating machine in removing the paper – clean or rough.

Perforations are measured by counting the number of holes in two centimeters. A perforation gauge makes this measurement an easy task.

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