Die proof (philately)

As a stamp is engraved it is necessary to check progress and a series of proofs are printed or 'pulled' from the die.

[1] Progressive proofs also form part of the design and approval process for a stamp.

Any changes made during this process turn the proofs into essays which may be identified retrospectively because they differ from the issued stamp.

[2] Once the die is completed, it is transferred multiple times to the plate from which the stamps are printed.

Any pulls from the master die after the stamp has been printed are known as posthumous die proofs and are normally produced for presentation purposes, as samples of the printer's work or to satisfy philatelic demand (demand for the item amongst collectors of stamps).

Die proof for the United States Jefferson issue of 1861
Approved proofs from Waterlow and Sons printers for a Bolivian stamp issue of 1943. (Subsequently punched for security purposes.)