Watermarks are intentionally created thin spots in paper.
Postage stamps are accountable paper. This means that stamps have monetary value, much like currency, until postmarks invalidate them for future use.The thinning occurs as the paper is manufactured, when a pattern is impressed into the paper while it is still damp. Once completed and dried, the paper will be put on a press where the stamp image is printed.
And like currency, postage stamps have been forged.
A watermark is a security measure that helps prevent counterfeiting.
Not every stamp has a watermark and, in fact, these days very few stamps have watermarks. But for collectors, watermarks still play a big role in organizing, valuing and determining the authenticity of stamps in their collections.
Some stamp collectors do not take the time to check watermarks on stamps in their collections, thinking it is too much bother and not worth the time and energy it takes to properly identify watermarks.
How one collects is a personal decision, but ignoring the details, such as watermarks and perforations, can lead to misidentification, and paying more for a stamp that is worth far less because it has a different watermark.
Watermark sleuths need surprisingly few tools to find and identify a watermark on a stamp.
A watermark tray, watermark fluid and stamp tongs are inexpensive and will successfully tackle most watermarking jobs. Your favorite stamp supply dealer will be able to fill your order, make recommendations and answer your questions.
Many watermarks that have been firmly impressed into the stamp paper can be viewed by simply turning the stamp face down and placing it on a dark background, such as the watermark tray, without any fluid on the stamp.
This is the fastest way to find a watermark, and it should be the first method you try.
If you cannot find the watermark by this method, the next step is to add two or three drops of watermark fluid on the stamp.
The watermark fluid makes the watermark visible for a short period of time without damaging the stamp or the stamp's gum.
Before you open the container of watermark fluid, be sure to read the warnings. The fluid is a chemical solvent, and many such fluids are flammable and might have noxious fumes. Keep away from flames, and open some windows when using watermark fluid.
Watermark fluid evaporates quickly, so you have to work fast to match the visible watermark on the stamp to the illustrations of watermarks that appear in stamp catalogs. Some collectors use lighter fluid (naptha) as a watermark fluid. It works, but it does not evaporate as quickly.
No matter what watermark fluid you employ, use tongs to remove the stamp from the watermark tray and place it face down on blotting paper or a paper towel. Let it dry completely before mounting the stamp in an album or placing it in a stock book.
There are electric watermark detectors that use lighting from the side and/or the back to show a watermark.
The electric watermark detector is by far the most expensive option, but it has additional advantages of bringing out flaws that might occur on stamps, such as repairs, creases and thins, though some of these can be seen with the watermark fluid as well.
Another type of watermark device uses sealed plastic pouches filled with dark blue ink. When the pouch is placed over a stamp and pressure is applied, the ink in the pouch will show the watermark. A roller that comes with the device is run over the pouch to reveal more of the watermark.
The pouch reveals enough of the watermark to identify it.
The ink-filled pouch is fast and less messy than using the watermark fluid with the tray, but if the pouch bursts under pressure, you could end up with ink all over your stamp.
When working with watermarks you might find yourself flipping back and forth through catalogs trying to find a match to the example sitting in your watermark tray.
Save time and eliminate the flipping by making photocopies taken from the catalog or other reference source of the watermarks you are likely to find on the stamps you examine.
Glue the photocopies to a single page. Be sure each watermark illustration is labeled with the watermark’s name. Then you only have one piece of paper to consult when determining the watermark.
If you make a page for every country you collect and save those pages in a binder, in due course you will have a very useful resource that has been personalized by you for your own collection.
Some watermarks are very difficult to detect. Trying all sorts of watermark devices might help. Sometimes using backlighting from a flashlight will make the difference. Try lighting from the sides of the stamp, too. If it is an expensive stamp and you still can't determine the watermark, it would be worth the fee to have the stamp expertized.
Working with watermarks is a learning opportunity. The more you engage in identifying watermarks, the better your skills will become. You might be lucky to find inverted watermarks, which often increase the value of the stamp. Watermarks also appear sideways to the left or sideways to the right, as well as in the more common position: upright. It is possible that parts of a watermark might be missing, or a watermark error might be found.
Occasionally, a wrong paper has been fed into a press, giving a stamp a completely wrong watermark.
That would explain how, in 1922, a gray 2-penny King George V stamp from Fiji that was supposed to be printed on paper watermarked Multiple Crown and C A (watermark 3 in Scott) ended up on Irish SE in Monogram paper (watermark 44 in Scott).
Mistakes happen, so check out those watermarks. You will learn more about the stamps you collect, and you might find treasure along the way.