Two stamps still joined together either horizontally or vertically. If the sheet gutter runs between, they are known as a

Gordon Piper. This article from the Philatelic Database archives was first published in the Philatelic Journal of Great Britain April

Gummed paper tends to curl and therefore certain stamps have been printed with the gum applied in narrow parallel bands,

In stamps having the same design on all values and printed from two plates. The key plate prints the general

Where more than one plate is required to print the stamp, the head plate is that which prints the portrait.

In some printing and perforating formats a blind stamp is left between two others or between a stamp and the

A security device in the form of wavy lines sometimes printed on the backs of stamps.

Another name for photogravure and similar printing processes operated under various trade names.

A form of multicoloured litho printing used by De La Rue and Co. Ltd.

A photographic glass plate used in the production of the printing plate in photogravure printing.

A stamp image or overprint, which shows hardly any ink due to an inking deficiency in the printing.

A term used to distinguish “ordinary” paper or printing from chalk surfaced paper or phosphor printings.

Perforation, which removes a diamond-shaped piece of paper from the whole instead of the usual round one.