Watermark

Also called: hallmark

A watermark is a logo, text or pattern that is added to printed matter, documents and photographs to prove authenticity or prevent the making of spurious copies.

The watermark finds its origin in paper production, where variation in the thickness of the paper can cause light and dark tones to appear when the paper is held up to the light. The watermark can also often be felt on the surface of the paper. Watermarks to prevent counterfeiting of official papers are used for paper money, among other things. Luxury stationery also sometimes contains a watermark.

A watermark can also be used with digital files, such as text documents and photographs. This can be a visible addition in the background or foreground, or an invisible attribute or key included in the metadata. These digital watermarks are usually added in such a way that they cannot be removed or only with a great deal of effort.

For documents and reports that are still being worked on, the term "draft" is often added as a watermark. Sensitive documents that are distributed to a select group of individuals do have unique attributes or watermarks added so that if pages are leaked, it is clear who leaked from the document.

Photographs are also often watermarked. This may be placed over most of the photo to protect the rights of a photographer or agency (as in a stock photo database), or smaller in a corner to make it clear who the owner or creator of a photo to be distributed is.