Postage stamp gum

Gum is a substance that is applied to the back stamps so that they can be glued by moistening a letter.

Production

Main components of the rubber are mainly plastics today. In most cases these are polyvinyl alcohol (PVA), a synthetic polymer based on carbon. First, we used arabic especially animal glues, somewhat later, herbal substances, such as dextrin or gum.

The rubber coating is now generally applied for technical reasons prior to the printing of the stamps. The rubber coating is done by machine. In the early days of stamps often these are gummed after printing. The lining was carried out in the absence of machines by hand with a brush.

Conservation

The preservation of the rubber is a key criterion of price in the Philately in unstamped brands. The Philatelist are three different quality levels:

• Mint - **: The rubber coating of the stamp is located in the state as it was available at the post office. This means that the rubber coating is perfect.
• Unused, Folded - *: The rubber coating of the stamp is located only partially in original condition. On the back, there is often a fold or crease remainders. Much of the collector rejects this conservation form. This folded stamps are considerably cheaper than fresh post. However, this also causes counterfeiters try to pass the gumming or otherwise recover, to give the impression of a mint stamp.
• Without gum, without gum - (* ): The rubber stamp is missing completely. Only very rare stamps are still collected in this condition form. Un-lagged therefore particularly often with false rubber coating to increase the value. One speaks of Nachgummierung (as opposed to original gum ) or recoating. Some stamps, such as in times of need, were issued without gum. Better preservation is therefore not possible.

In most stamp catalogs unstamped stamps are rated according to this scheme. The abbreviations (asterisk) apply internationally.

Special forms

However, the philatelist is not only concerned with the conservation of rubber, but also with their appearance and structure. Example, there are differences in the color, shine some rubber linings, others are striped or grainy. Specific types of rubber are:

• Spargummierung
• Trockengummierung
• Grooved rubber
• Self-adhesive rubber

Over time, many different Gummierungsarten of stamps have been developed since the individual postal administrations often experimented with the composition of the rubber coating. The German Federal Post Office experimented example, in the years 1955 and 1956 with a rubber coating with Peppermint flavor. This Pfefferminzgummierung should, in contrast to the normal gum, leave a pleasant taste on the tongue while licking the stamp. These experiments were, however, discontinued after one year but not more taken up until today.

In tropical areas were dispensed frequently because of the high humidity throughout the rubber coating of the issued stamps. The stamps would otherwise be more likely to stick together. There, they are similar to stickers peel off sheets (eg, Brazil).

Harmful gumming

However, the gum can also destroy a postage stamp. Thus, the German Empire expended for example Stamps ( Ostropablock ) with a sulfuric acid-containing gum, the increasingly damaged the stamp after a few years. For older brands may occur through breaks in the animal glue at a fraction of the entire stamp. In such cases, the rubber must be replaced immediately to prevent falls apart the entire stamp.