Editing Overprint (section)

== Specimen overprints ==
{{main|Specimen stamp}}
Some stamps are never valid for postal use. They are made for use in promotional displays or as reference material by postal authorities and the [[Universal Postal Union]] (UPU). Still others are manufactured by printers for [[Color management|color matching]] throughout successive printings. In all such cases, the stamps will display the word [[Specimen stamp|"specimen"]] (or "cancelled") on its face. Occasionally, the word may be uniquely handwritten by a postal authority or, much more elaborately, punched through the stamp paper in a method known as [[perfin]]. Most often, though, specimen markings are applied as a prominent overprint.<ref name="Williams"/>
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Colombia 1888 Sc137 Muestra.jpg|[[Postage stamps and postal history of Colombia|Colombia]], 1888: Overprinted ''muest''(''ra'') (Sp.)
Stamp-Natal 1902 £20 green.jpg|[[Postage stamps and postal history of Natal|Natal]], 1902: Specimen for a £20 stamp
Australia-1924 Specimen stamp overprint.tif|[[Postage stamps and postal history of Australia|Australia]], 1924: Specimen overprint
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