Using a watermark detector for stamps
Detecting watermarks on stamps can be frustrating even with the use of a watermark detector. This is strange, because watermarks were introduced to stop the production of counterfeit copies with the intention of defrauding postal services.
Why Use A Watermark Detector
Most postal services have tried out using watermarks on stamps. During the period of 1895 to 1916 adhesive postage stamps issued by the United States were printed on watermarked paper. Two different watermarks were used. The double watermark was used until 1910, and then the single was used until 1916. (See image to see the watermarks). Most countries have stopped the practice of using a watermark on stamps. However, Great Britain has used them for their whole history of issuing stamps.
A stamp watermark is the same as that of any paper watermark. It is an area of thinner paper produced during production that can be seen when the paper is held up to the light. However, once a stamp is printed on the paper the watermark is difficult to see this way, if not impossible.
During the period that a stamp is manufactured different processes and paper can be used. This can mean different watermarks on stamps or no watermarks at all on some of the stamps issued. Thus, stamps that look the same can actually be different because of the watermark. They are considered different by stamp collectors and will have different listings in stamp catalogs.
The watermark of a stamp can make a big difference in the value of a stamp. It is for these reasons that using a watermark detector is important.