Postage Due stamps were authorized in 1879 and were unique, since they were the first stamps issued which didn’t prepay for the delivery of mail. Instead, they denoted the amount of postage due on mail that was insufficiently prepaid. This amount was paid not by the sender, but rather by the recipient of the letter.
Designed solely for functional purposes, the stamps were plain with large numerals indicating the amount to be paid. For twenty-five years, this design remained unchanged – although the colors varied from a brown to red brown to a deep red. These first issues were printed by the American Bank Note Company and were released on July 1, 1879.
In 1894, the Bureau of Engraving and Printing took over the contract for producing the Postage Due stamps, and the design changed slightly. While the early issues featured the numeral in an oval, these new releases had the value figure in a diamond.
In 1930, the Bureau of Engraving and Printing changed the designs so that the numerals were featured in a half-circle. The following year, in 1931, the Bureau of Engraving and Printing changed the format of some of the stamps slightly – a horizontal format was used as opposed to the vertical one used previously. The design remained the same, however.
In 1959, the Postage Due stamps were printed in two colors for the first time. The designs of these issues were similar to the 1930-31 stamps. However, the border and background were printed in a carmine rose, while the numerals were printed in black. In addition to the color change, new values were also used. In 1985, the Postage Due stamps were discontinued by the Postal Service and are now obsolete.