Yes, you were a young stamp collector before you called yourself a philatelist. But even in those early days it was not long before you came across the term “watermark” as it applied to stamps. The idea that two otherwise identical stamps could have hugely different values because of something to do with a watermark intrigued you. And, you may have studied some of your stamps and the catalogs to find these.

But how do we define watermarks? Why are they used on stamps (and also on postal stationery)? How are they made? And perhaps, most importantly to us, how best to detect them?

Internet websites, and even some philatelic ones, are awash with various definitions: that the watermark shows as a “thin” area of the stamp, that it lets a greater amount of light through that area. Yes, it may appear so, but, in fact, no fibers have been removed from the paper. “Thin” in philately has a specific and usually unwelcome meaning in the description of a damaged stamp, and we should try and reserve it for those unfortunate occasions. What actually happens in the production of most watermarks is that the fibers of the paper are compressed. Thus, the suitable philatelic definition of a watermark is a design that shows as a density variation and increased translucence in the paper.

Figure 1. The world’s first postage stamp, Great Britain Scott 1 (left) and the world’s first philatelic watermark (right).

Why do we have watermarks? Perhaps we should start with a little history. Watermarks have been in use on specialized paper and bank notes for centuries (with the earliest recorded usage from Italy in the 13th century). Great Britain’s Rowland Hill, in proposing the world’s first postage stamp as part of his proposed postal reforms, was very concerned that the chosen design should be safe from forgery. To this end, the Penny Black, introduced to the world in May 1840, came with superbly detailed line engraving and the provision of individualized check letters for each of the 240 stamps on a sheet – and he required that each stamp should have a watermark (Figure 1).

Hill, following the completion of the treasury competition that led to the selection of the Penny Black’s design, was in almost continuous contact with the printers, Perkins Bacon and Petch, on many aspects of the stamp’s production.

Hill’s records, however, show very few deliberations or discussion about the watermarking. The first indication we have of such in his diary is the entry for October 10, 1839, when he records a conversation with the director of the French Stamp Office, Monsieur Cordier, who expressed to Hill, “a very decided opinion that a peculiar watermark in the paper … will completely set at nought all risk of forgery.”¹ 

In addition, one of the four winners of the £100 prize money in the treasury competition (which closed on October 15) was Benjamin Cheverton who, although his design was not chosen, clearly influenced Hill’s thinking in suggesting that the design should include “an embossment of a female head of the greatest beauty to be executed by Mr. Wyon” and adding that “… the stamps should be in rolls of two hundred and forty stamps on security paper with a watermark.”² Hill, of course, chose Willam Wyon’s head of the young Queen Victoria on the City Medal of 1837 for the design. Production and watermarking of the handmade paper for the stamps would be a completely new and difficult project. Time was of the essence in the overall project to produce the stamps. Hill passed the control of this part of the work to his elder brother, Edwin.

Edwin was a civil servant, engineer and inveterate inventor, in whom Rowland had the greatest trust. The contract for the manufacture of the paper was with Stacey Wise of Rush Mills, near Northampton, which brings us to how watermarks are made. 

Early paper was handmade. It was formed by pressing the pulp into a wire mesh tray-like mold. The Small Crown watermark “bits” were formed of small pieces of brass wire which were bent into the crown shape, and stitched to the flat wire frame in each position. It is here that we now see the pressing of the pulp onto the wire “bit” causing the density variation in the paper that we referred to in the definition of the watermark – all the pulp is still there, but when the removed sheet is dried, the watermark shows as a lighter area.

Astonishingly, each of the Small Crown “bits” was handmade, thus tiny differences arose. These are not readily identifiable, but even in early Penny Black days we see the arrival in the catalogs of watermark errors. For example, the printers inadvertently placed the paper upside down (i.e, wrong end first) on the printing plate, thus “watermark inverted” is listed for nearly all the Penny Black plates, although some are much scarcer than others. More about errors later.

With the success of postal reform and the introduction of stamps, the demand for stamp paper increased dramatically. It was not long before a mechanized means of the paper production took over and with it, when watermarking was required, a mechanized means of applying the watermark to the paper.

Figure 2. Principle of the dandy roll, left. Right, an early dandy roll, courtesy Robert C. Williams Museum of Paper Making, Georgia Tech.

In 1826, an Englishman named John Marshall invented an item called a dandy roll, which he used in the watermarking of handmade writing paper. Looking like a giant rolling pin, the first dandy rolls had a mesh around them with the watermark “bits” attached, so that the rolling motion produced continuous watermarking in a moving paper sheet being fed under it (Figure 2).

As the process developed, Rush Mills and other stamp papermakers incorporated the system, which, as it progressed, came to use rolls on which the watermark shapes had already been incorporated during manufacture.

A further development of the dandy roll concept led to cylinder mold watermarking, whereby differing depths of design are incorporated in different levels of the paper, giving a three-dimensional and depth variation effect. This system is hugely expensive and time-consuming to produce. Today, its main application is in banknotes rather than postage stamps, as the forgery of bank notes has been and can be financially damaging at a national level. 

The idea of having a watermark in the stamp was to dissuade the unscrupulous of the world in trying to forge the stamp. But are stamp watermarks ever forged? 

Clearly, the making of a stamp forgery does require a forged watermark if the original stamp has a watermark. How would that be attempted? Techniques for this include scraping (to produce a more translucent area), rubber stamping, printing with chemical inks, and using translucent oils such as linseed. Moving into more recent times, another method that has been recorded is the use of a translucent polymer, such as thin epoxy resin. A similar action to add a watermark to a genuine stamp would, of course, render it a fake. However, even the most famous forgers such as Jean de Sperati shied away from forging watermarks, preferring instead to use decolored stamps – usually of a lower value or less valuable issue – with a genuine watermark.³

The first question you should ask when you notice that a stamp’s watermark does not look as it should is: “could it be an error?” Watermarks can be misplaced or simply incorrect. We saw in the case of the Penny Black that incorrect printing procedures led to inverted watermarks. Procedures in later years led to watermarks that were sideways, reversed, inverted and combinations of those. Often, watermarks may change when an issue of stamps goes on for many years and a newer watermark is adopted. A prime example of this is the transition from Crown CC to Crown CA in many early British Commonwealth issues. Even in modern times errors still occur. The otherwise common 1953 2½d stamp from Gibraltar can (rarely) be found with an inverted watermark (Stanley Gibbons 149aw). But the most exciting error in the catalog is usually the “incorrect” watermark. To search for an example let us look at the U.S. stamps in our albums.

Figure 3. “USPS” watermark paper, courtesy of Scott Specialized.

Figure 4. “USIR” watermark paper.

The United States came late into watermarking, at least as far as stamps are concerned. Two watermarks were used between 1895 and 1916. They consist of the large letters “USPS” in different fonts repeated in lines across a sheet of stamps, and are notoriously difficult to see, as in most cases only a part of a letter is visible on an individual stamp. The watermarks are labeled numbers 190 and 191 by Scott Specialized Catalogue of United States Stamps & Covers (Figure 3).

Figure 5. U.S. stamps of 1895, Scott 271 and 272 (usually found with watermark 191, seen in Figure 4) can be found as varieties 271a and 272a with the USIR watermark.

In parallel, the U.S. Internal Revenue Service used similarly marked paper, but using the letters “USIR” (Figure 4). At some point during the printing of the 1895 Bureau Issue, USIR paper was inadvertently used for some of the 6¢ Garfield and 8¢ Sherman stamps (Figure 5), thus some of these have a “USIR” watermark. Finding a “U” or an “S” on the back of these stamps, however, is not enough to claim it as a rarity because the watermark is considered identical to the regular watermark for these stamps. Only stamps showing all or part of an “I” or “R” can be considered as the valuable variety.

Figure 6. From the U.S. Presidentials of 1938 is a USIR watermark variety of Scott 832, which is usually found unwatermarked.

A more remarkable error occurs 43 years later when USIR paper makes another appearance, this time on the normally unwatermarked $1 Woodrow Wilson stamp of the Presidential Issue of 1938. This stamp, Scott 832b, has the advantage of truly being the variety, in that any part of the watermark – the letters “U,” “S,” “I,” or “R” clinches it (Figure 6). The American Philatelic Service’s expertizing department (APEX) has issued certificates for some 31 of these issues, including a used block of 20. The most recent certificate is dated December 2020.

We should finally look at how best to identify a stamp’s watermark.

Figure 7. The first nine Great Britain watermarks shown are surface printed examples. Note the increasing complexity of the designs, including the “emblems” that gave rise to fascinating errors. Courtesy of publishers of Stamp Magazine.

The usual description of a watermark is as seen from the back of a stamp, and this is how the Scott and Michel catalogs show them. Stanley Gibbons, on the other hand, shows them as seen from the front of the stamp. 
We started by saying that a watermark is an area of increased translucence, so the most obvious and simple method is to hold the stamp to the light – and in some cases this is all that is required. A scanner, by virtue of the extremely bright light that it uses, will sometimes show the watermark of a stamp on cover – proven examples of this include the sometimes quite complex watermarks of the Great Britain Victorian surface-printed issues (Figure 7).  

Beyond trying to see a watermark with bright light, the next step is to use a dark tray – usually black, where the stamp is placed face down and moistened with watermark fluid. This enables the more translucent watermark to show itself against the darkness of the tray. Stamps of some colors, particularly yellow and orange, can be particularly reluctant to show their watermarks. Here, the trick is to employ a base of the complementary color – so in those two cases you need to find a surface or tray in purple or blue.

Historically, lighter fuels or benzene have been the go-to fluids for watermark detection, but the health and accident dangers of these are considerable. Fortunately, Clarity watermark fluid was developed relatively recently under the guidance and cooperation of the APS. Clarity is non-flammable, non-toxic, and is completely safe for the environment. It should be the fluid we all use now.

Lastly, we should look at the commercial electro-optical equipment available to us – such items as the Safe Signoscope, the Lighthouse Sherlock and the Stanley Gibbons Spectrum. These are, of course, very convenient, but will nonetheless leave your wallet several hundred dollars lighter. The more advanced of these are now incorporating filters, enabling the complementary color selection advantages mentioned above to be tried.

Finally, both the fluid and optical identification methods find use in the detection of damage and repairs – not infrequently the search for a watermark shows up unsuspected physical problems in a stamp.

Countries vary greatly in their use of watermarks. We have covered the United States’ short period of use, and the three fascinating errors it produced. Great Britain and the British Commonwealth are fertile areas of research, having produced a plethora of variations and errors over the years. Conversely, Belgium and France both started issuing stamps in 1849. Belgium produced watermarks from the outset, but metropolitan France, next door, has never used them. Several South American countries have a wide and diverse watermark selection, with some astonishingly complex designs. Brazil and Argentina in particular are among the most prolific users of philatelic watermarks.

Whichever area of collecting you pursue, it is worth checking catalogs for watermark details – be they errors or simply a run of different types in an unchanged stamp design. So check your collection, your duplicates, and your I’ll-sort-it-out-one-of-these-days box. An unusual watermark could make you wealthier than you thought.

Endnotes

1. Quotes from Rowland Hill’s diary entries are from the biography Life of Sir Rowland Hill, KCB and History of Penny Postage by De La Rue, available from archive.org or found occasionally second-hand.
2. Quoted in Robson Lowe’s book The British Postage Stamp.
3. The website https://www.sperati.org/UltimateSperatiAuction.pdf offers much information on this famous forger.