Error card
An error card is a card printed with a mistake, such as a misspelled name, wrong details or the wrong photo. When the maker corrects it during the print run, both the error and the corrected version exist.
In more detail
Wikipedia's article on error cards shows a T206 card of Sherry Magee with his name spelled Magie. CGC's glossary lists misspelled names, wrong statistics and the wrong photograph as common errors, and printing faults count too, such as a back printed upside down, or a card issued with another player's back.
Which version is scarcer depends on timing. A correction made early in the run leaves few error copies, and a late one leaves few corrected copies; an error the maker never fixed is called an uncorrected error. CGC notes that the version printed in smaller numbers is the one that may carry a premium.
CGC Cards grades error cards and asks for its Error designation on any card with a printing error, at no extra fee. Not every oddity counts: Wikipedia notes that hobby references often treat differences in card stock or color as variations rather than true errors.
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