About the Sale
This Auction is a stamp collector's dream! Filled with vintage United States Plate Blocks dating from 1960 to 1971, each page is a piece of art un to itself worthy of being framed. Each page gives ...view morea brief description of the meaning of each of the mint stamps housed on the page. A wonderful collection of American history.
A plate block is a block of stamps from the edge of the sheet which shows the plate or cylinder from which the stamps were printed.
Until the late 1960s, United States stamps included two rows of stamps attached to one another in a block of four or more, with printing information, including the printing plate number, on attached margin paper. A number is used to identify one specific plate or cylinder used to print the stamps.
Then plate block collecting changed in the US due to the addition of up to eight multi-digit numbers which represented different colors used to print the stamps. The numbers were printed along the selvage. This meant collectors needed many more stamps to save a single plate block.[4] This lasted for about ten years before the post office reverted to the traditional single number for most stamps.[4] In a press release dated Dec. 10, 1980, the postal service announced a new plate numbering system that would, except in cases where more than four designs appear on a pane, "establish a plate block as consisting of four stamps regardless of the number of inks used or the press used to print the stamps."[5] Now, new issues often begin with a number such as "11111," with each digit in a different color.[1] Stamps printed in large quantities may have multiple plate numbers so the next plate combination might be identified as "22222" and so on.[1]
Collecting
The usual practice in plate block collecting varies by country and era; the classic 20th century US plate block consisted of a 2 x 3 block in the middle top, bottom and/or sides of the sheet for flat plate issues (a 2 x 2 block in the corner of the sheet for rotary press issues). Ambitious collectors will seek to own blocks displaying every known plate number for the stamp; specialized stamp catalogs will list these. They may also collect all of the block positions, such as the numbers of each corner that exist after a large sheet is quartered.
https://en.wikipedia.org/wiki/Plate_block#Background