A 1901 4c Pan-American invert stamp with a $70,000 estimate will be among the star lots of the Curtis Collection sale at Robert A Siegel on November 7 in New York.
Issued on May 1, 1901 by the US government to mark the Pan-American Exposition in Buffalo, New York - the six Pan-American denominations feature black and white images of transport and infrastructure surrounded by coloured frames.
As a result of errors in the dual colour printing process, the 1c, 2c and 4c denominations were susceptible to inversion.
The 4c edition was released to the post office as the result of a misunderstanding. 400 copies were printed, with around half being overprinted "specimen".
As with the majority of 4c inverts, the gum is disturbed, due to being removed from mounting paper.
This example also features "margins to touched" at the bottom, a thin spot at the upper right and a perforation tear to the upper left - but is otherwise a fine example.
A 2c Pan-American also features with a valuation of $55,000. The rarest of the three inverts, only around 200 were released through the post office.
As with most inverts in the issue, it features slightly disturbed original gum and perforations just touching at the top.
Earlier this year a used 2c Pan-American invert sold for $38,350 at the Flagship Series sale in New York.
A 1c Pan-American will also appear, with an estimate of $12,500. The most common of the three inverts, this example is in fine condition with only a barely perceptible corner crease at the bottom right.
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