What is a watermark?
If you hold a piece of writing paper up to the light you may see a design of some kind. The design may include the words “rag content” and a picture of an eagle, crown or some other symbol such marking are called “watermarks.”
Watermarks are trademarks which paper makers put in their better quality paper to identify the grade of paper and the paper mill where it is made.
Here’s how the paper maker puts the watermark in the paper:
When the paper is being made it passes under a special roller on which is fastened the watermark design.
The design presses into the soggy paper, leaving it a tiny hit thinner where it comes to contact with the design. When the paper dries, the thinner place show as a watermark, which can be seen clearly only when the paper is held up to the light.
Watermarks are sometimes put in stamps and in paper money to prevent counterfeiting.-Dick Rogers