This refers to when a sheet of stamps has a line of small holes at the edges to make it easier to tear the stamps out the sheet without damaging the rest. Perforations are something of a tradition. Even recent self-adhesive stamps have had perforations for decoration although they do not need to be separated as they peel individually from backing paper. Perforations are a very important part of a cover’s condition. Most of our stamps arrive from Royal Mail in sheets of 25 or 50 and so one of our team has to separate all the stamps ready to be stuck on the cover. This can be a nerve-wracking job when you first start!