Plate Block Collecting

Plate numbers were put in the margins of United States sheets so that later the printer would know which sheets were printed from which plates so that plate wear and damage could be monitored. Collectors noticed the marginal numbers and began at first collecting single stamps with the selvedge attached as an adjunct to their collection. The Bureau of Engraving and Printing began printing US stamps in 1894 (before that our stamps were printed by private printers under contract so when our government took control of its own stamp printing it could be called one of the first examples of insourcing-which will be the new trend down the road after we have outsourced everything). At first with Bureau issues (as these post-1894 stamps are called), collectors tried to obtain them in strips of three with the plate number and inscription attached. Then, beginning about 1920 the fashion changed to collecting the plate numbers in blocks of six. The reason for the change from three to six had mostly to do with the small number of new issue stamps that the Post Office issued between 1909 and 1930. There were many coils and watermark and perforation varieties but very few design changes during those 20 plus years. Collecting plate number blocks of six added spice to what what was becoming a mundane hobby. When the use of rotary presses around 1930 changed the placement of plate numbers to the corner and reconfigured plate block collecting to plate blocks of four, the specialty really took off. And there were so few new issues and so much postal use that collectors could easily buy a sheet of each issue, save the plate block, and use the rest as postage. Plate block collecting has declined in the last twenty years largely because there are so many new issues that it is hard to keep up and because the various printing methods used have eliminated uniformity of plate numbers and where they are placed. Further, the ingenious marketing ploy of the USPS of issuing most stamps in mint sheets of 20 has made it far easier (and from the post office’s point of view far more expensive) to just save those larger sheets.