The Find of a Lifetime: Pan-American Exposition Invert Stamps Error Discovered by APS Member

The Find of a Lifetime: Pan-American Exposition Invert Stamps Error Discovered by APS Member

It’s every philatelist’s dream: to find a hidden gem in amongst a long-forgotten cache of stamps, covers, and souvenir sheets. One long-time member of the American Philatelic Society, who asked to remain unnamed, discovered one of these gems when he finally uncovered a souvenir sheet that he had purchased from the US Postal Service eighteen years earlier. This 2001 souvenir sheet, for the Pan-American Exposition Invert Stamps Centennial, lay untouched for almost two decades before its secrets were revealed.

Scott 3505 variety (error)

Pictured here is the sheet in question, which prominently features a significant color omission on a souvenir sheet created for the purpose of celebrating errors. The Pan-American Inverts issues (Scott 3505), released on March 29, 2001, were designed to commemorate the centennial of three of the best-known United States stamp errors: the 1c, 2c, and 4c Pan-American Exposition bicolors of 1901, which were printed with their central vignettes inverted in relation to their frames. The Postal Service endorsed the replications of invert errors as an opportunity for collectors and stamp novices alike to enjoy seeing and using a famous invert that they might not otherwise be able to experience.

The 2001 souvenir sheet (view the sheets side by side below) features replicas of the three famous inverts, and was created using the original engraved dies from 1901. The stamps were designed to appeal to traditional philatelists and are therefore as close to precise replicas as possible, the only difference being the small “2001” date on the bottom left of the reproductions. The souvenir sheet also includes four 80c stamps that were replicated from a 1901 cinderella stamp created to promote the Pan-American Exposition.

pan american inverts no errorScott 3505 variety (error)-1

When the sheet’s owner discovered the error in his collection, he sent it to the American Philatelic Society Expertizing Service (APEX) to have it expertized. APEX’s expert, specializing in errors, freaks, and oddities, notes that “Due to the upward shift of the colored intaglio sleeve, a color omission occurred: green on 1-cent, red on 2-cent and brown on 4-cent. A new major error.”

APEX certifies the sheet as the United States Scott 3505 variety: green omitted on No. 3505a, red omitted on No. 3505b, brown omitted on No. 3505c, unused, full original gum, never hinged, and genuine in all respects.

The American Philatelic Society’s Director of Expertizing, Tom Horn, points out that the three perforated stamps with the inverted vignettes “do not have any speck of the color that is supposed to be printed on them.” Therefore, if someone were to remove the stamps from the souvenir sheet, you would have three stamps with missing colors.

Horn also reminds us that there is typically no value assigned to new discoveries until they are sold.

So, for all of those who wonder whether printing errors still occur in the digital age, the answer is a definitive “yes” – you just have to keep a sharp eye out to find them. In the meantime, we can all enjoy the novelty of this error-of-an-error.


Details about Pan-American Inverts (Scott 3505) and its design come from U.S. Stamp Yearbook 2001, written by George Amick and published by Linn’s Stamp News.

 Image of the 2001 Pan-American Inverts (sans error) comes from the APS StampStore.

APEX has been authenticating stamps since 1903 and has added images to its certificates since the late 1960s. Since 2004, APEX has stored scans of submitted items, which are searchable online at Our group of experts number more than 160, covering most of the stamp-issuing entities of the world. Additionally, we have an extensive Reference Collection of genuine, fake, counterfeit, forged, and altered stamps and covers to support the certificates we write. The Collection is available for members to use for their research here at the American Philatelic Center. Details on how to use this service can be found on the APS website:

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