Digital Watermarks


Writers, photographers, musicians, and artists are among those who have taken advantage of the worldwide publishing opportunities provided by the Internet, yet these same people -- all considered "authors" under U.S. copyright law -- are frequently being taken advantage of by on-line pirates. Given the ease with which audio and visual files can be duplicated, it is no surprise that such duplication on the Internet regularly occurs without the rightful owners' permission. This is where digital watermarks come in.  In explaining how exactly digital watermarks affect our everyday life, and what role they play in technology today, I think it best to refer to the infamous case of NAPSTER. 

Napster was the free Internet software that allowed people to share and download music from one another, free of charge.  The only problem was that the record companies did not believe this process to be fair.  If people could download their favorite artists songs for free and then burn a CD, then why would they buy the actual CD.  The music industry was going to lose money.

History of Digital Watermarking

·        Digital Watermarking started back in 1979, but it was not until 1990 that it gained popularity.
·        No one person is credited with founding or inventing the digital watermark
·        Still in its growth stages today, and with cases like Napster, it is showing more and more reason to have digital watermarking.

Digital Watermarking Technology

Digital watermarking, sometimes called "fingerprinting," allows copyright owners to incorporate into their work identifying information invisible to the human eye. When combined with new tracking services offered by some of the same companies that provide the watermarking technology, copyright owners can, in theory, find all illegal copies of their photos and music on the Internet and take appropriate legal action.

·        Watermarks can be viewed with either stand alone technology or plug-in play software
·        Watermarks reveal either:
·        A unique identification code that can be traced to the copyright owner.
·        Complete copyright ownership information.
·        “A pattern of bits inserted into a digital image, audio or video file that identifies the file's copyright information (author, rights, etc.). The name comes from the faintly visible watermarks imprinted on stationery that identify the manufacturer of the stationery. The purpose of digital watermarks is to provide copyright protection for intellectual property that's in digital format.” (Definition from webopedia)

Side Effects of Digital Watermarking

A decision on how much information to include in a digital watermark is consistent least three factors:

1.      The larger amount of information stored on a digital watermark, results in a more distorted picture.  For example, a unique identification code is small and requires less alteration of an image, while a full-blown copyright notice plus the author's address and telephone number requires greater alteration.

2.      Copyright owners may move or assign their ownership interest to another party. Thus, current information that is accurate today may be obsolete in the future.

3.      Some companies are offering their digital watermarking software at no charge and thus make some of their profit by charging annual fees to copyright owners for maintenance of on-line current contact information.

Tracking Digital Watermarks

In order to track the digital watermarks, so that copywriters know where their digital watermark appears on the Internet, there has been robot like programs made.

·        MusicBot, introduced by BMI, is a new web robot designed to gather market information and music trends while monitoring the use of music in cyberspace.

·        MarcSpider, produced by Digimarc (the self proclaimed “leader in digital watermarking technology”), searches the web for images embedded with digital watermarks.

·        This technology allows copywriters.

·        These search tools are still very new and have a while to go until being perfected.

Although we know that digital watermarking will not stop people from taking what isn’t theirs on the Internet, it does however prevent them from doing so without knowledge.  If an image is watermarked then a warning sign will pop up, telling the consumer that this image is copyrighted.  Another added feature of the watermark, is that for audio files, any watermarked software will not play on the realplayer juke box, nor will the play on portable cd players.

Examples of Watermarking Technology

Below is a photo of a watermark (left photo) and then another photo showing how the watermark is applied onto a normal picture (right picture). Click this IBM Web Page for an example.

Digital Watermarking Problems

Digital Watermarks, although highly useful, have some serious problems that must be addressed.  Although the companies who make digital watermarks, such as Digimarc, and SignumTech, claim that the watermarks can survive image alteration and resizing, an article published by the NY times stated otherwise.

“Resizing, compressing and converting images from one file type to another may add noise to an image or diminish its watermark in such a manner that the watermark becomes unreadable.”(NY times)

The search engines created to find the watermarks, are only allowed to access sites that are freely available, meaning that if your site is password protected then the robot cannot sweep your site for copyrighted images.


·        Copyright protection
·        Labeling
·        Tamper Proofing

Beyond Copyright Protection

Digital Watermarking also serves as a means of advertising within digital imagery. For instance, a user may download and view a digital image, use a watermark reader to extract the digital signature, then access a web-based directory to find the company's name and up-to-date address, phone number, and web and e-mail addresses. (This was a brief excerpt in the NY times, nothing mentioned of it on other websites.)


Digital Watermarking provides for the protection of intellectual property in the digital world. Just as plagiarism runs loose in the real world, unauthorized copying of data, whether it be audio, visual, or video, exists in the cyber world and is accomplished with the click of a mouse. Digital Watermarking attempts to copyright the digital data that is freely available on the World Wide Web to protect the originator's rights.

Links of Interest

Webopedia Definition of Digital Watermarking

Digimarc’s Home Page: Leader in digital watermarking

Secure Digital Music Initiative (SDMI) – News that These Watermark Codes have Been Broken

History of the SDMI Challenge