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How To Tell If A Stamp Has A Watermark Using UV Light

Stamp watermarks were popular in the late 1800s and early 1900s. Not every stamp had a watermark, though, which makes identifying the stamps that do quite tricky. It’s therefore useful to understand the different ways to tell if a stamp has a watermark.

UV light does not reveal stamp watermarks except in extremely limited conditions. The easiest and most effective way to identify if a stamp has a watermark is to hold it up to the light. After that, the most effective way is to use a watermark tray and watermark fluid to reveal the watermark.

While some methods of identifying a watermark on a stamp are easier than others, few are failsafe. Some can damage a stamp, while some that will not damage a stamp are not completely dependable. Below, we go through the pros and cons of each method, after we give you an overview of stamp watermarks.

What Is A Watermark And Why Is It On My Stamp?

Stamps had barely been created before people started trying to cheat the postal organizations that used them. Cancellation marks were blurred and written over, counterfeit stamps appeared out of nowhere, and just about any other way a stamp could be copied or reused was implemented as soon as people thought of it.

In response, postal organizations produced new and inventive ways to thwart the cheats. Here are just a few of those methods:

  • Changing stamp backgrounds to make it harder to obscure a cancellation mark
  • Making cancellation ink impossible to cover over
  • Broadening cancellation marks to ensure it marked the entirety of the stamp
  • Using indelible ink cancellation marks
  • Engraving stamps
  • Mechanical cancels that destroyed the stamp paper
  • “Fugitive ink” that ran at the slightest hint of moisture
  • Using invisible ink that can only be read by a machine

Another method that was popular in the late 1800s and early 1900s was the watermark. The paper a stamp was printed on had a watermark that was almost impossible to replicate. If the watermark was not present, the stamp was a counterfeit.

What Is A Watermark?

A watermark is a design or pattern that is put on paper. It is not part of the design or artwork on the paper or created by the ink used to create artwork, but is actually part of the paper itself. Watermarks are created during the paper manufacturing process.

How Watermarks Are Made

Paper starts out as wet, pulpy fibers that are laid in a tray. Before the pulp dries, metal wires are pressed into the pulp and the paper thins where the wires touch it. This creates a watermark.

The wires, or bits, can be molded into a design. That design is imprinted into the pulp at regular intervals. The design is the watermark. It is replicated over the entire run of whatever type of paper is being printed.

Watermarks were used on:

  • Stationary
  • Envelopes
  • Stamps
  • Official documents
  • Books
  • Invoices

With a watermark, a company or government organization could signify the official and authentic nature of that document, preventing forgeries. This included marking official runs of stamps for governments all over the world.

History Of Stamp Watermarks

The earliest recorded watermark was made in 1282 in Italy. Watermarks were incorporated into stamp design in Europe around 1860 (the very first stamp was printed in 1840). The purpose was to thwart counterfeiting by creating a stamp that couldn’t be reproduced except by the printing process that had that watermark.

One question many people have is “why would anyone counterfeit stamps or try and reuse them?” The answer to that is simple economics. Before stamps, postage was prohibitively expensive for most people, and sending one letter often costed an entire day’s pay.

Making Postage Affordable

Stamps reduced this cost and made postage affordable for even the common man, but that didn’t stop people looking for a bargain. The average wage per week for most people was under $20, so even the cost of a single stamp had to be worked into a family budget.

That created a market for counterfeit stamps and, when possible, reusing authentic stamps. Postal organizations responded by implementing several anti-counterfeit measures.

Watermarks In The USA

In the USA, the earliest watermark used on a stamp was in 1895 (the “double-line USPS”). The US Bureau of Engraving and Printing had taken over the production of stamps from the American Banknote Company in 1894.

In taking over the production, the Bureau also assumed control of all existing stamps, dies, rolls, printing plates (used, unused and for future use) and all paper stock from American. Because of the timing, the Bureau did not have the means to make their own designs, dies and plates.

It was important, though, to produce stamps that were clearly different than what the American Banknote Company produced. That reality forced the Bureau to get creative. The answer the Bureau came up with was to print triangles in the upper corners of the stamp design. These became known as the Triangle Series of 1894.

Incorporating Watermarks

The triangles worked, but the Bureau wanted more of its own “signature” on postage stamps. It had been printing money and securities as well as revenue stamps since 1862 and had been using watermarks on all of the above since about 1878.

Legally, all government securities had to be printed on watermarked paper. Technically, stamps fell under the umbrella of “securities,” which meant that a watermark should be included on the paper of all stamps. The Bureau, however, did not begin including watermarks until late 1894.

The reason was likely two-fold:

  • To save money as they won the contract by having the lowest bid
  • To avoid having to dump a lot of existing stamps and paper stock

The first US stamp with a watermark was issued in April of 1895. The first usage was on May 2 of that year. The timing of this is interesting because it indicates that the primary reason the Bureau started using watermarks was because of the securities requirement rather than addressing a pressing counterfeit issue.

2 Cent Chicago Counterfeits

Part of the reason many suppose the Bureau started to use watermarks was the discovery of 2 cent George Washington stamp counterfeits. On March 31, 1895, the Chicago Tribune ran an advertisement from an organization in Canada that offered the stamps for sale.

The sale of these stamps was unauthorized, and the Bureau had not printed the stamps in question. This was the first documented attempt to defraud the United States Postal Service. One major “tell” of the counterfeits was that authentic 2 cent George Washington stamps were engraved, while the stamps offered for sale were lithographed (no etching, so lithographed stamps are smooth to the touch).

Why Counterfeit Stamps Were Probably Only One Factor

The main issue with the “watermark because of fraud” supposition is timing. The advertisement ran at the end of March/beginning of April. The first watermarked stamp was issued on April 29, 1895. There simply was not enough time between the discovery of the counterfeit and the issuance of the watermark for that to have been the reason.

To move to a watermarked stamp, the Bureau would have had to:

  • Decide by committee to print the watermarked paper
  • Design and approve the new watermark
  • Produce the paper with the watermark
  • Print the stamps and let the ink dry (which usually took about a week)

Adding to this conclusion is the fact that the Bureau did not add a watermark on 15 or 50 cent stamps until sometime later (almost two years later after existing paper stock was used up).

There are three reasons the Bureau likely decided to go ahead with the watermarked paper:

  • US Securities law
  • To separate Bureau stamps from the American Banknote Company’s
  • To make counterfeiting more difficult (this was certainly one reason, but probably not the driving factor)

United States Postage Stamp Watermark

The first watermark used for securities was “USIR,” which stood for “United States Internal Revenue.” To simplify the postage process and design, that watermark was altered to read “USPS,” or “United States Postage Stamp.”

In 1909, that watermark was reduced in size to save paper costs and to try and strengthen the paper by marring it with less of a watermark. The size reduction was primarily achieved by migrating from a double line USPS to a single line.

The Bureau used watermarks until 1916, when World War I demanded further cost cutting. Unwatermarked paper was less expensive than watermarked paper. Additionally, it was determined that the single line watermark was not a deterrent to counterfeiting. Since then, stamps have been printed on unwatermarked paper.

The Watermark Irony

Postage stamps incorporated the watermark at least in part because of a desire to control counterfeiting. For many stamp collectors today, spotting the watermark on a stamp is extremely difficult. Essentially, watermarks are just thinner parts of a paper segment and not part of the inked design.

The irony is that the watermark has been successfully duplicated in forgeries over the years. Partial designs on counterfeits have tricked less experienced collectors and led them to purchase what they thought was authentic, only to find out afterwards that it was a fake.

While there are several ways to spot a watermark, none are foolproof, and all require a degree of interpretation. Any time there is interpretation, there is room for both mistakes and fraud.

Watermark Terms

Simple – This is a complete watermark design on each stamp.

Multiple – This is when a watermark is duplicated across a stamp multiple times.

Sheet – This type of watermark is large and applied across an entire sheet of stamps. The design only appears on some of the stamps and only on a portion of it. The result is that an exceedingly small portion of the watermark is actually visible on any individual stamp.

Stitch – This type of watermark is an accident. It happens when the seam of a drying belt imprints upon the paper, leaving an indent on the paper the stamp is printed on. These are entirely random and usually only affect a few stamps.

Things To Consider When Checking For Stamp Watermarks

Spotting a watermark requires a fair amount of skill. At the very least, you must know what you are looking for or you will not usually be able to easily spot one. Methods mentioned below are tried and true and just about anyone can implement them without risking damage to their stamps. While there are many ways to identify a watermark, there are only a few that will not damage a stamp.

It Must Be Effective

This is defined as a better than 90% chance of accurately showing a watermark and accurately detailing it is shape and form. Any method that does not show the shape or at least a general form is not included in our list.

It Must Have A Reasonable Chance Of Not Damaging The Stamp

This is self-explanatory. While using alcohol and lighter-fluid is listed on here as a method to reveal the watermark, and they obviously have the potential to damage a stamp, they can still be used safely. If the stamp is left to dry, it will emerge as good as new. Most damage occurs when stamps are prematurely handled. This is especially true with gum damage.

If a person handled the stamp before it has dried, the corrosive nature of the liquids can eat away at the gum. The same, however, can be said for watermark fluid, which is considered harmless to stamps when the proper directions are followed.

The Stamp Must Be Left In Near Identical Condition

The method of watermark exposure should not further damage or mark a stamp. If damage existed before the exposure, the stamp must emerge after the treatment with identical or near identical characteristics. Additionally, once revealed, the method used should not change the appearance of the stamp. Let’s now take a closer look at methods of identifying stamp watermarks.

How To Tell If A Stamp Has A Watermark Using UV Light

The reality is that UV light does not usually work on watermarks. You can hold the stamp up to a UV light and you might be able to see parts of it brighten, but unless the stamp is treated with a substance that illuminates when shown in UV light, your results will be disappointing.

Stamps have been treated since the 1950s in various nations with nearly invisible luminescent ink “bands” that show up on stamps when the stamp is shown under a UV light. The purpose of this was to make sorting and postmarking mail easier.

Increased Automation

UV light and computerized equipment would identify the stamp location on an envelope and a machine would flip the envelope so that the postmark could be applied on the backside. The entire process happened in a fraction of a second.

The process of applying the luminescent bands to a stamp was called “tagging.” The bands could be applied virtually anywhere to a stamp because they were almost invisible to the naked eye. Tagging was done in blocks, bars, bands, and in the margins or across the stamp.

To see the luminescent bands, expose the stamp to a UV light. Be careful to take all recommended precautions when working around a UV light. You can damage your skin and eyes with overexposure. Extreme overexposure to your eyes can lead to burnt corneas and even blindness. So, be careful!

How UV Light Could Reveal A Watermark

The only way UV light can help identify a watermark is if one of the bands of luminescent ink overlaps the watermark. If that happens, the UV will reveal the ink taking on the form of the watermark.

The issue is that watermarks, at least in the USA and Europe, have not been used in official postage stamps for more than a century, except for some commemorative stamps. So, the stamps with watermarks would not have the luminescent ink and the stamps with luminescent ink would not have the watermarks.

How To Tell If A Stamp Has A Watermark Using Regular Light

This is perhaps the easiest way to spot a watermark. The light shows through more easily and clearly where the watermark is located. Hold the stamp up to the light and look for the design. The light will catch the thin part of the paper and the paper will “light up” in comparison to the rest of the stamp.

How To Tell If A Stamp Has A Watermark Using Watermark Fluid

You can purchase watermark fluid at any store that sells stamp collecting supplies. To use this method, you will also need a watermark tray to put the stamp and fluid in and tweezers or tongs to handle the stamp.

Place the stamp in the tray and saturate it with the fluid. The black of the watermark tray will show through the watermark. The area surrounding the watermark will retain its normal color. Once the stamp dries, the watermark will disappear.

Watermark fluid is the best liquid to use because it is formulated to not damage the stamp. Specifically, it will not damage the gum on the back of the stamp, even after saturation. The downside is that watermark fluid has an extraordinarily strong odor.

A Secondary Benefit

Watermark fluid reveals just about any crease, thinness or tear in a stamp. It is great to use when making a major stamp purchase as it does not damage the stamp but can help you verify that you are getting the quality product for which you are paying.

Other Ways To Tell If A Stamp Has A Watermark

Use A Dark Background

If you do not have watermark fluid, you can lay the stamp down against a black background. This will sometimes reveal the watermark without fluid. The risk in using this method is that sometimes micro-creases will make it look like there is a watermark when there is not actually one there. For this method, you really need to know what you’re looking for.

Rubbing Alcohol Or Lighter Fluid

In a pinch, these can be used to reveal a watermark if you use them the same way that you use the watermark fluid. The risk is that both can damage the stamp. Both can affect the gum, which can dissolve and damage the rest of the stamp. Additionally, both fluids have oily ingredients that can lead to decomposition of your stamp.

Optical Watermark Detector

These contrast your stamp against a concentrated bright light. The stamp is placed inside a box against an acrylic block. A light is shown through the block and the watermark’s features are lit up. These machines can be very expensive but are also about as failsafe as you can get.

Portable optical watermark detectors typically run about $50 to $100. Less portable machines can cost anywhere from $200 up to $600. The range indicates differences in capabilities and reliability. A $600 optical watermark detector for a stamp is overkill, for example, unless you are dealing with exceptionally valuable stamps quite regularly.

Morley Bright INST-A-TECTOR

This is an inexpensive piece of equipment (usually about $35 online with ink packets costing about $8) that highlights watermarks using an ink packet. You place your stamp in the box, face down, and a transparent envelope with blue ink is pressed on the stamp.

The ink collects on the thinner part of the paper (in the envelope, not on the stamp), and reveals the watermark. The stamp remains undamaged.

Final Thoughts

While UV light can help with identifying watermarks in certain conditions, it’s by far not the most effect method. Watermark fluid is the best, but scanners and bright light work as well, and you can even use rubbing alcohol or lighter fluid if you’re very careful.

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