Most often, though, specimen markings are applied as a prominent overprint.
From the en.wikipedia.org
Other rarities include an Icelandic 5-aur stamp from 1897 with a provisional overprint.
From the nytimes.com
Woe be to the dollar should the U.S. overprint it-because there was a euro to bail out to.
From the forbes.com
The other stamps are Lithuanian, one with overprint in Lithuanian and in German, the other without.
From the en.wikipedia.org
The search for philatelic income was the motivation for this overprint, more than the political update.
From the en.wikipedia.org
In some situations, however, months or years may be included in the overprint to indicate an expiration.
From the en.wikipedia.org
Biological overprint of the geological carbon cycle.
From the nature.com
It is up to the money creators to not overprint.
From the infowars.com
On validation, an overprint was added, giving the tramstop code, time and date of validation and the point of validation.
From the en.wikipedia.org
More examples
Something added by overprinting
Print (additional text or colors) onto an already imprinted paper
An overprint is the addition of text (and sometimes graphics) to the face of a postage stamp or banknote after it has been printed (although some overprints are solely in the selvedge area of souvenir sheets). ...
Overprinting refers to the process of printing one colour on top of another in reprographics. This is closely linked to the reprographic technique of 'trapping'. ...
(Overprinting) Printing over an area that has already been printed
(Overprinting) The usual term for the process of creating pre-marked maps. This traditionally involves a second printing process, adding the course to a map on which the terrain details have already been printed.
Overprinting means that all the separation colours not used in the foreground colours are transparent, and the background filters through in these areas.
New material printed on a map or chart to show data of importance or special use, in addition to those data originally printed.
A term used to describe the characteristic of an overlapping foreground element allowing a background element to print in the same area. Overprint is the opposite of knockout. ...