Specimen versions of petroleum stamps:

Specimens are examples of stamps that have been defaced in some way to prevent
unauthorized postal use. This generally is done so that the stamps can be used as
models, review copies or display examples of stamps that have been produced
or might be produced at some later date. Such stamps may be sent by
postal services to other countries to insure recognition of their stamps
as postally valid, to individual post offices as display copies, or to the
philatelic press for publicity purposes. Other copies may be produced
by printing companies for design approval or advertising purposes.

Latin American specimens commonly are overprinted
with the word "muestra".

This trial proof of a Mexican petroelum production tax stamp is pin
perforated with the word "MUESTRA", indicating that it is a specimen.

Other Latin American specimens are overprinted with
that word, especially when the specimens were
produced by British or American printing
companies. Indeed, the bottom stamp shows
the name of the printer along with the word
"specimen" in this item produced for advertising
purposes. The holes in the stamps are an
added security feature .

Addtional Latin American stamps are overprinted
with the word "specimen" by the postal services
of UPU countries upon receipt of the stamps as
examples of valid postage (as in this
Venezuelan stamp overprinted in Angola).

The colors of specimen overprints can vary even within a
single set in order to contrast with the stamp color.

These two UPU presentation cards include
the same stamps with red and black specimen
overprints (see enlarged view of the
petro-stamp with a black overprint). It is not
clear why two versions were created.

In a few cases, specimen
stamps also carry an imprinted control
number for added security.

An unusual specimen from Tonga (highly enlarged here) that contains
very small pinholes, arranged diagonally through the center of the
design, that spell out the word "specimen". These would be
easily missed in a cursory examination of the stamp.

Most other specimens from Tonga are overprinted with
the word "specimen" in a variety of type sizes.

Specimens of petro-stamps from Germany and West Berlin
show the standard German "Muster" overprint. Many
forgeries of these and other specimen overprints
exist and buyers should be careful to get their
stamps guaranteed or expertized.

Japanese specimens are overprinted
with the symbols shown above and
are termed "mihon" overprints.

© Peter A. Scholle, 2000

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