People ask me all the time about watermarks and watermark detectors - some collectors don't even know that they exist on stamps. Most modern stamps do not have watermarks on them, most likely due to the cost of manufacture. A watermark is typically impressed on the base paper by a "DANDY" roller, which contains the watermark design, during the early stages of paper manufacturing.
Since the same stamp could catalog at 10 cents or $1,000 all
depending on the WATERMARK, it becomes imperative that you know i your stamp has the watermark or not. Stamps sometimes come with the watermark
imprinted inverted or sideways or inverted on the same stamp design. And collectors value them differently.
Now on to how to find out if your stamp has a watermark. The oldest and least expensive method is using watermark fluid and a watermark tray. You simply place the stamp face down in the tray, and place a small amount of watermark fluid on the back of the stamp. Hopefully the watermark can be seen. The fluid then evaporates, leaving your stamp unharmed, just needing to dry. A time consuming process to see many stamps. Not to mention, the difficult in analyzing the design of the watermark.
This is why SAFE invented the Signoscope. The world's first optic, electric watermark detector. It operates only on glass, pressure and light. No fluid is required and your stamps are never endangered. You simply place the stamp in the tray, tighten the pressure, turn on the light and you see the watermark (or not).
These watermark detectors have the added benefit of being able to detect even slight variations in the thickness of the paper, making it very
effective at spotting repairs and forgeries. Even as simple as whether the stamp has been hinged in the past.
To this day after 25 years of using the Signoscopes, I am amazed by their simplicity and convenience. They have paid for themselves over and over!
