Watermarks provide a unique criterion of quality for handmade paper. They are created during the process of paper production, leaving the watermark as an intrinsic component of the sheet. Paper is the only material that supports this graphic meta-level. Watermarks are created by attaching a form (text, graphic, symbol, pattern, etc.) directly on to the screen of the mould. This results in a image that is visibly lighter or more transparent than the surrounding paper.
They can serve as a security feature to identify the paper as authentic or added to the paper as a trademark.

Over and above such implementations, watermarks can also be used to realize graphic and artistic ideas according to one’s own personal designs. ( www.sheryloring.org , www.maxmarek.de , Siân Bowen , Tayfun Erdogmus )