We offer The Best of the Stamp collecting true gems of Postal history Inverted Centre Stamp Liberia Scott C68v, Sellinger 53. 1952 25c. Ashmun Air Mail issue marginal block of four with inverted center. Stamp depicts John Marshall and Yehudi Ashmun and map of Marshall, Liberia between them. According to Sellinger, more than 200 of each exist. Some stamps used to require a second or third manual feed through the printing press after changing the ink in the press. When the sheet was accidentally fed upside-down for its second passage through the press, an inverted centre would result.
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