People can be exposed to benzene in the environment from gasoline fumes, automobile exhaust, emissions from some factories, and waste water from certain industries. Benzene is commonly found in air in both urban and rural areas, but the levels are usually very low. Exposures can be higher for people in enclosed spaces with unventilated fumes from gasoline, glues, solvents, paints, and art supplies. Areas of heavy traffic, gas stations, and areas near industrial sources may also have higher air levels. 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 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 Silence in the face of adversity is the father of complicity and collusion, the first cousins of conspiracy.. It is a useful tool to look at the watermarks and all the small details on stamps clearly. It’s a simple tool to use with no complex parts when may need any kind of replacement….”

Has multiple colour settings for the LED light source, which can also be adjusted in brightness to assist with watermark identification, by the two switches on the side.

I'm curious about the Morley bright detector, just i'm wondering why it has been kept out of production... link to USA 1975-1981 Americana Coils #1613-19, 1811-16 category 1975-1981 Americana Coils #1613-19, 1811-16

link to USA 1898 Universal Postal Union Colors #279-284 category 1898 Universal Postal Union Colors #279-284 I know that's a simplified example, but look closely of illustrations of the watermark possibilities for your stamp first. There are usually clues - the shape of a crown or the detail of a letter or symbol - which you can train yourself to look for.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. The Roll-a-Tector sachet contains a viscous colored goop contained in a thin but strong, sealed plastic bag. The bag is placed over the stamp and a roller is run over the top until most of the goop is forced away from the stamp, leaving a little extra goop in the paper depressions forming the watermark. Under Enhance on the menu, go to Enhance-Adjust Lighting-Brightness/Contrast. Then increase the contrast to 100 and the brightness to around -85 and this really brings out the image. 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 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 plastic needs to be strong enough to protect the stamp and flexible enough to reveal the watermark Place stamp face down in unit close and apply pressure using thumbs to reveal watermark. When the unit is closed the special 'ink' within the sachet will flow into the watermarked section of the stamp, allowing you to clearly see the design of the watermark, whether its inverted, the position of crowns and scripts and other important watermark features. No I am not a chemist but was just interested to find out what exactly I have been using to detect watermarks.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 your Watermark Detector Tray add a small amount of Watermark Fluid, just enough to submerge the stamp. Place the stamp face-down and its watermark should become visible as soon as the stamp is submerged. The stamp shown on the right has a watermarked "S" on it. 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. I followed the above advice last night, for 10 Straits Settlements stamps that I was having a hard time finding the watermarks on. I was looking for either 'Crown CA' or 'Crown CC' watermarks. But when I discovered Equalize I knew it was a winner. You go to Filter – Adjustments – Equalize in the menu structure.

Now, I’m not sure that all these steps are necessary but it’s amusing to try them out and see if they can help with working out those watermarks that can make so much difference.

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.