Watermark is an identifying mark pressed into paper as it is formed by a papermaking machine. Usually, it is the mark left by wires bent into the watermark pattern and attached to the dandy roll of a Fourdrinier machine (see Paper [diagram: How paper is made from wood]). As the wire pattern comes into contact with the layer of wet pulp, a translucent impression is made, which can be seen when the finished paper is held in front of a light. A mark that looks like a watermark can also be produced chemically on finished paper. Watermarked paper is often used for important documents to help prevent counterfeiting.
