Background image or text in a document is known as ________.

A watermark is a logo or text superimposed on an image to help prevent an image from being copied or allow others to know where it was copied from and who owns the rights. Watermarks are often used on web pages so that the site's logo or banner is always visible in the background. A digital watermark is a kind of marker covertly embedded in a noise-tolerant signal such as an audio, video or image data. It is typically used to identify ownership of the copyright of such signal.