When the master die of the Series of 1908-09 4¢ Washington stamp was first made, the denomination was expressed in words, which was a violation of Universal Postal Union regulations. While lower values containing denomination spelled out in words went to print as they were, the design of the 4¢ value was changed to correctly state the denomination in a numeral. Early Series of 1908-09 printings were made with plates featuring a standard spacing of 2mm between the stamps, a marginal imprint of the Bureau of Engraving and Printing, and a plate number. About 10% of the sheets had to be discarded because paper shrinkage caused faulty perforations. To fix the problem, star plates were introduced with 3mm vertical spacing between the six outer rows on each side of the full sheet of 400 subjects. The rest of the spaces remained at 2mm, since the inner stamps were less impacted by shrinkage. This new process decreased the waste to about 1%.