Because of the elaborate process necessary for the full-color printing, the Bureau of Engraving and Printing contracted with a private firm, the American Bank Note Company, to produce the series - the first U. S. stamps to be printed by a private company since 1893. Uniquely among U. S. issues, the sheets lack the plate numbers usually printed on the selvage surrounding the stamps. In the places where the numbers normally appear on each sheet, the name of the country is substituted, engraved in capital letters.