An underprint is an inscription on the back of a stamp, usually under the gum. An underprint has not been practised on all stamps, but has been used now and then.
Information printed on the back of a stamp:
- Information for the public, e.g. the occasion of the issue (U.S.A., Portugal).
- For protection; the name or initials of the organisation which bought the stamp and which alone may use it.
- Counting number (Dutch coils).
When printed under the gum the underprint will survive soaking.
Uniform Penny Post
From 10 January 1840, letters posted within Great Britain were charged on a basis of a uniform postage rate of 1d. In the beginning of the 19th century postal rates were collected on delivery and the postal rates were very high. Rowland Hill was the man who concluded that the postal service needed to be reformed.
In 1839 the parliament passed the Uniform Penny Postage act in Great Britain. The uniform penny rate came into force on 10 January 1840. This law paved the way for the first stamp (penny black) and prepaid envelopes (Mulready).
At the U.P.U. conference held in Washington in 1898 all member states were recommended to print in green, red and blue for stamps representing their equivalents of 5, 10 and 25 gold centimes. The recommendation was confirmed by the Rome Conference in 1906 and became effective in most countries.
Disruption of currencies and postal charges made this uniformity very difficult. In 1934 the U.P.U. decided that the colors would represent postal services (one unit weight) in stead of cash values:
- Green (Printed papers)
- Red (Postcard)
- Blue (Letter)
These colors had to be used for stamps on foreign mail. After the Second World War stamps were more and more printed in two or more colors and this system was abandoned too.
A stamp is unused when it does not have a cancellation mark and the stamp does not have all of it's original gum (compare: mint).
If the original gum has been removed or damaged by a hinge we call the stamp "unused". A stamp that has been "hinged" is worth considerably less than the same stamp in mint condition.
United Postal Union
The United Postal Union (U.P.U.) was formed in 1874. The union embraces every country having an organised postal service. Its conventions regulate international relations between postal administrations of the world.
If a stamp has been cancelled we call the stamp used. Sometimes a cancelled stamp has not been really "used" in the mail.
Many countries have cancelled stamps to satisfy collector's demand and sometimes sold more cheaply than unused. These stamps are not always distinguishable from postally used. Only when a special postmark is used or the original gum is present these stamps can be identified.
Before certain countries and colonies issued postage stamps, post offices or agencies were set up in those territories by other countries. Contemporary in those post offices stamps were used of that other country. Stamps of Great Britain, France, U.S.A. and some other countries have been used abroad. Stamps used "abroad" can only be identified by the postmark.