In 1894, when the Bureau of Engraving and Printing took over the printing of United States stamps, each plate employed was designated by a numeral printed in the margin paper (or selvage).
Early printings of Scott 249, the 2¢ carmine lake George Washington stamp, bear plate number 1. When plate 1 was exhausted for this issue, another 29 plates were used with different numbers. More were used to print the slightly different colored Scott 250 in carmine.
Within a year, two-digit numbers were required for additional issues, and several years later, three- and four-digit numbers came about as plates wore out or new issues were printed.
By the latter part of the 1910s, five-digit numbers were required, which provided for an additional 90,000 plate number possibilities, then considered a lifetime supply.
A few multicolor issues appeared, and some of them employed different plates and, therefore, two different plate numbers.
Examples from 1931 include the 2¢ black and red Red Cross (Scott 702), and the 2¢ carmine rose and black Surrender of Cornwallis at Yorktown commemorative (703).
Bicolor airmails included the 1918 24¢ carmine and rose Jenny Biplane (Scott C3) and the 1928 5¢ carmine and blue Beacon (C11).
The BEP kept churning out stamps, mostly in one color, but some in two, and most collectible in plate blocks of four stamps.
And then along came the 1968 6¢ Angel Gabriel Christmas stamp (Scott 1363).
Different colors were employed to produce this issue on the multicolor Huck press, with multiple plate numbers printed on the selvage in such a manner that it required a strip of 10 for a collectible plate block.
And that’s not all. Many hundreds of different plate number combinations resulted from the blue, brown, and yellow plates, collected in both top margin and bottom margin positions.
For some collectors it was a tremendous challenge. Others saw it as a major financial drain and a headache to collect.
To make matters worse — much worse — within the next two years collectors saw the 1969 6¢ Christmas Winter Scene (Scott 1384), the 1970 6¢ Flag and White House (1338D), and the 1971 8¢ Flag and White House (1338F).
These new issues followed the same format as the 1968 Christmas issue, with hundreds of multicolor plate numbers, and plate blocks of 10 and 20 with top and bottom positions.
The U.S. Postal Service, newly reorganized in 1971, must have realized that huge numbers of these large plate strips, referred to as “biggies,” were being assembled and held by collectors, dealers and investors. More “biggies” followed in the 1970s, such as the 10¢ Crossed Flags with a plate block of 20 (Scott 1509), the 10¢ Horse Racing commemorative with a plate block of 12 (1528), the American Bicentennial issue with plate blocks of 10 (1559-1562), the 13¢ Eagle definitive in the Americana series (1396), and others that required eight to 20 stamps for a proper plate block.
The challenge became too much for the old-time collectors, and newer collectors resisted these issues firmly. They resented the problems the big plate blocks presented, including the cost for album space and added expenses such as oversize mounts.
Dealers chose not to stock many of these “biggies” either.
The net result was that plate block collecting, long a mainstay of U.S. philately, dropped off considerably.
By the early 1980s the Postal Service realized this, after having resisted suggestions that instead of running the plate numbers up and down the selvage, the numbers should be bunched to create traditional plate blocks of four. The USPS developed a new scheme to limit the space needed for the plate numbers: the code system.
A five-digit plate number would be replaced by a single-color coded digit reflecting the color used for that printing. The 18¢ Yorktown/Virginia Capes issue, a multicolor commemorative, has 49 different digit combinations of seven numbers each; one for each color used in printing. What a disaster that would be with real five-digit BEP numbers running up and down the margin. Instead, the collectible plate block was back to four stamps with the new system.
Part of this new system, perhaps to create additional revenue, was the decision to place a plate number at the top of every booklet pane, and periodically at the bottom of a coil stamp.
For many early coils printed on the Cottrell press, these numbers appeared every 24 stamps. Plate number coil collecting, first as strips of three and soon after as strips of five became almost an instant hit, particularly when some plates were short-printed and various scarce items came to light.
Thus, the 1981 18¢ From Sea to Shining Sea Flag coil (Scott 1891), a non-Cottrell printing, is very common as plate No. 5, while a strip of plate No. 6 of the same issue sells for close to $2,000 today, and was even more 10 years ago.
The codes were recorded by the BEP, and the real five-digit plate numbers were known but not widely disseminated. This code system continued for about 27 years. During the 1990s, the BEP was printing only a fraction of the stamps, and other stamp printers were used to create U.S. stamps.
The main contractors are identified by prefix letters before the plate number: A is American Bank Note Co., P is Ashton Potter, S is Sennett Enterprises, V is Avery Dennison. Avery’s stamp printing division was sold to CCL of Canada last year, and its stamps now have the prefix C. The Bureau of Engraving and Printing no longer prints U.S. stamps.
Things went along well until 2007, when David Failor, then the head of the USPS Stamps Division, made the very controversial decision to eliminate the consecutive numbering of plates with every plate being called No. 1, regardless of the number of plates employed for the printing.
Thus, for example, the Yorktown/Virginia Capes issue would have only one collectible plate block number instead of 49. Any change of plate number would only take place if some production change occurred like a change in paper or ink source.
Ridiculous, isn’t it? Change the printing plate and don’t change the plate number; change the paper source and change the number.
Failor’s motives are not fully clear, even today. It has been estimated that this change cost the USPS about $1 million per year.
This move effectively doomed most of the collecting of plate blocks by those who went after all numbers and positions and, to a lesser extent, impacted the collecting of plate number coils and numbered booklets.
Maybe someone within the Postal Service will realize how much this affected plate number collecting — and the USPS bottom line.
Maybe there’s hope yet.