United States: 1869 30 cents pale carmine and pale ultramarine, error flags inverted, used.
Engraver: National Bank Note Co.
The 1869 issue of postage stamps for the United States comprised values from 1 cent to 90 cents. The 15 cents to 90 cents values are printed in two colours requiring two passes through the press.
Copies of the 15 cents (showing the landing of Columbus), 24 cents (showing the Declaration of Independence) and 30 cents (showing flags) were printed in error with one of the colours upside down or inverted. These are some of the rarest stamps of the United States.