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The simplest example of an easily seen watermark is in the paper currency of most countries. It is yet another measure taken to prevent counterfeit. Holding a sheet of good quality bond writing paper against a light will reveal a faint, almost invisible, trademark of the manufacturer. Watermarks are also found on many of the older stamps from the US and a few other countries.

The process of printing, or rather pressing on the watermark is a simple process. Watermarks are impressed into the paper during manufacture. While the paper is still wet, either a wire device, raised letters on a roller, or a rubber design on a wheel is used to press the watermark into the paper. At the place where the watermark is pressed in, the paper becomes thinner, thus allowing the watermark to become visible.

Some stamps from all over the world have these tiny hidden emblems. Usually they are designs that show the name of a papermaker, initials of a country or one of its agencies, where it is manufactured, or crosses, crowns, roses, leaves and other designs. We will explore why they are there, how they began and why they are of importance to philatelists.

First of all, watermarks existed long before stamps. In fact the first stamp in the world, the Great Britain Penny Black of 1840, carried a watermark: an almost unnoticed, small crown imbedded in its paper. When paper for those stamps was ordered by the British Post Office, the specifications required the maker to place the watermark in the printing paper so that it would appear on each of the 240 stamps in the full sheets.

Naturally the original intention was not to increase the value of the stamp or such. Watermarks in stamps, as in banknotes, were just one more measure taken to prevent counterfeiting. As an added precaution, the paper manufacturer was not permitted to supply that kind of marked paper to anyone but the British Postal Office's printers.

Throughout the 1960's, dozens of different watermarks were used in British stamps. For the same reason, security, other countries too used watermarked paper. The United States however, did not use watermarks for its stamps until 1895. From then on, until about 1916, the initials "USPS" were found in one form or another on most U.S. issues.

In the US stamps, watermark letters are found in both double-line and single-line styles. Sometimes the individual letters are clear on each stamp and at others the initials were spread out so that the back of one stamp may carry only the portion of one or two letters from 'USPS'. However, since the issue of the 3c Victory - the first airmails of 1918 - the Bureau of Engraving and Printing has ceased using watermarked stamp paper - except for the back-of-the-book revenue issues. These carried a "USIR" (United States Internal Revenue) watermark until 1958.

The dates given are not definite and should not be taken as final proof. To be sure, catalogues should be checked to see which stamps did and did not carry watermarks within that period. For example, the first four U.S. Special Delivery issues do not carry watermarks, the next five do, and since then, no Special Deliveries carry any.

Out of curiosity, what do those mysterious, hidden watermarks have to do with stamp collecting? The answer is simple: Dollars and cents. The watermarks have as much impact on the value of the stamp as they do on their proper identification.

Of considerable importance is the careless nature in which the work of creating watermarks was carried out. Just as in the case of stamps - where manufacturers and governments cared little about details in their manufacture - there was a careless attitude in the making of watermarks. It is well-known that there are similar stamps in varying shades and colors because no one cared if the mixture of ink at the second printing was a little off-shade. In the same way, if the first issue of a stamp came with a watermark, there was no real care to make sure that in a second printing, the exact same watermark was reproduced. If there was some hurry in issuing a second printing, paper without the proper watermark was often used, though care was taken to make sure that the quality was similar in all other aspects.

For philatelists: the presence or otherwise of a watermark can make a huge difference in the value and scarcity of many stamps, not only for stamps from the United States, but from most other countries of the world as well. 

Finding the watermark on stamps may prove to be an illusive exercise. Sometimes the watermark can be seen when we point a stamp (held with a pair of tongs of course) with the printed side facing a bright light. However, many of the watermarks have been so faintly impressed that they cannot be seen in this way. Yet others may only be faintly visible because they are overpowered by the designs or the printing ink.

A quick solution, and a practical one, is to use watermark detectors which are available in the market. These are essentially boxed-in, powerful light sources that are used with filters of various colors which will effectively block out the colors that stand in the way of spotting the watermarks. The problem is that not all of them work well. For inexperienced collectors, they may present problems because the right color filter is required before the watermark may become visible.

Some dealers use watermark fluid (usually a form of benzene) to track a watermark quickly and surely. These fluids, as well as the small black glass trays, enameled metal or plastic that will be required, are available from stamp dealers.

In using the fluid, the following steps will be helpful:

1. Place the stamp face down in the black tray.
2. Pour enough fluid to just barely saturate the stamp - usually only a drop or two would be sufficient.
3. When the stamp is wet, the watermark will stand out boldly - but not very clearly and for only a few seconds. (The fluid exposes the thinner portion of the paper - the watermark - and the black tray becomes visible through the pattern for a few seconds. One has to be quick to spot the watermark as it disappears fast - as the volatile fluid evaporates.)