Can Postmarks Be Faked?

(There has been a recent change to the term "pictorial postmarks" rather than "pictorial cancellations" by the USPS.) There are some examples of "faked covers" produced by philatelic forgers, most usually to increase their value, in which the postmark has been altered in some way; for example, by changing the date.

Is it possible to back date a postmark?

It is the policy of the Postal Service to prohibit backdating and pre–dating of mail except in the following cases: ... When all requirements for postmarks are met by a customer but postmarks are not applied because of errors by Postal Service personnel.

Does postmarked mean mailed?

Postmarked is the verb of the term postmark and it means to stamp with such a mark. ... For Example : If the application form says it has to be postmarked on or before January 1st, 2010 it means that it has to be mailed on or before January 1st, 2010 and the postmark will reflect that.