Watermark
A
watermark is a design made by impressing a water coated metal stamp or roll onto
paper during manufacturing. The result is a pale shadowy image that is clearly visible when the paper is held up to the light. Watermarks originally were used to identify paper manufacturers. They were introduced into modern
Europe in
Italy in
1282. They have also been used on
postage stamps,
currency and other government documents to prevent
counterfeiting.
Encoding an identifying code into digitized music, video, picture, or other file is known as a digital watermark.