Overlooking Perforations

Sometimes in the rush to make comparisons between the size of stamp frames in order to distinguish between flat plate and rotary press U.S. Bureau of Engraving and Printing (BEP) and Canadian British American Bank Note Company (BABN) stamps, the importance of perforation measurements is overlooked. Overall, sheet-fed flat plate printed stamps were perforated by a different perforator than web-fed rotary press printed stamps.

Sheet-fed flat plate printed sheet and booklet stamps were mostly perforated by two one-way sheet-fed flat plate rotary wheel perforators with one perforator for horizontal perforations and with one perforator for vertical perforations. Flat plate coil stamps were perforated by this same perforator but only in one direction either horizontally or vertically.

Web-fed rotary press printed sheet and booklet stamps were mostly perforated by one two-way web-fed rotary press bar and wheel perforator that perforated in two directions both vertically and horizontally in one machine. Rotary press coil stamps were perforated by a bar perforator in one direction only either horizontally or vertically.

The exception to this was BEP web-fed rotary press printed and unperforated coil and sheet waste that was cut up into sheets and perforated by sheet-fed flat plate perforators in two directions. Also, some coil stamp web-fed rotary press printed rolls that were already perforated by a bar perforator in one direction were cut into sheets and perforated in the other direction with a sheet-fed flat plate rotary wheel perforator.