QUESTION: What is a watermark?
ANSWER: There are two different meanings
for the word "watermark" that are relevant to the electronic-publishing
Our company does not sell software that deals with digital watermarks, but we
do sell both server-based and desktop software that can apply various kinds
of visible watermarks to the pages of PDF files. Click here to find out about such software.
- The term "watermark" is used to refer to faintly visible
text or graphics that are embedded in sheets of paper when the paper is
manufactured, printed on the pages of a
paper document, or embedded in the pages of an
electronic version of a document.
Embedded watermarks are often found in very high quality stationery and
in security papers (such as papers used to print checks or stock certificates).
Printed watermarks and visible electronic watermarks are often used to
call attention to the status of a document or to make people aware of the
the proprietary nature
of a document.
For example, people sometimes put a watermark that says "DRAFT"
on a preliminary version of a document in an effort to ensure that anyone
reading the document is aware that it is not the final version.
Here are samples of three watermarked pages:
- The term "digital watermark" refers to a pattern of information
inserted into a digital image file, digital audio file, or digital video file
that identifies the file's copyright information (author, rights, etc.).
The purpose of digital watermarks is to provide copyright protection for
intellectual property that's in digital format.
Unlike printed watermarks, which are intended to be somewhat visible,
digital watermarks are designed to be completely invisible,
or in the case of audio clips, inaudible. Moreover, the information
representing the watermark is scattered throughout the file in
such a way that it cannot be identified and manipulated.