paper; ink (carmine rose and blue) / engraving; adhesive
Height x Width: 7/8 x 1 in. (2.22 x 2.54 cm)
United States of America
May 14, 1918
Mint 24-cent perforate stamp with the central image inverted; position 70, plate number 8493.
This 24-cent stamp represents plate position 70 of the only sheet of 100 inverted Jennys sold by the Post Office Department.
This most famous U.S. stamp printing error occurred at the Bureau of Engraving and Printing, in Washington, D.C., the week of May 6 13, 1918. The bi-colored 24-cent Jenny stamp paid the rate for the first airmail service, which was scheduled to begin May 15, 1918 connecting Washington, Philadelphia, and New York. One sheet of 100 stamps with an upside-down image of a blue airplane escaped detection. The biplane pictured in the design is the famous JN-4-H “Jenny” modified by replacing the front cockpit with a mail compartment.
When the error occurred, either an inverted carmine frame sheet was fed into the small hand press for the second impression or the plate printer, after inking and wiping, placed an inverted blue vignette plate into the press. The undetected error sheet was sold to William T. Robey on May 14, 1918 at the New York Avenue post office. The lucky collector sold it to Eugene Klein, a Philadelphia stamp dealer, for $15,000. Klein in turn sold the sheet to collector Colonel H.R. Green, who broke it into blocks and singles, kept some, and sold the rest. The discovery and subsequent sales received enormous press attention.