Visible watermarks change the signal altogether such that the watermarked signal is totally different from the actual signal, e.g., adding an image as a watermark to another image. Stock photography agencies often add a watermark in the shape of a copyright symbol ("©") to previews of their images, so that the previews do not substitute for high-quality copies of the product included with a license.
Visible watermarks can be used in following cases :
* Visible watermarking for enhanced copyright protection.
In such situations, where images are made available through Internet and the content owner is concerned that the images will be used commercially (e.g. imprinting coffee mugs) without payment of royalties. Here the content owner desires an ownership mark, that is visually apparent, but which does not prevent image being used for other purposes (e.g. scholarly research).
* Visible watermarking used to indicate ownership originals.
In this case images are made available through the Internet and the content owner desires to indicate the ownership of the underlying materials (library manuscript), so an observer might be encouraged to patronize the institutions that owns the material.