Imprimatur (philately)

In philately the word imprimatur refers to the first stamps printed from an approved and finished printing plate.

[1] The term is particularly associated with British Victorian stamps as it was the practice of the printers to retain the first sheet as a record.

[1] The word is from the Latin "let it be printed".

[2]

An imprimatur of the 1870 rose-red three halfpence stamp of Great Britain from Plate 3. In the collection of the British Postal Museum and Archive .