What steps can be taken to prevent digital image files from being used illegally?
One of the biggest hurdles photographers face in distributing their work in digital form today is how they can protect their images from unauthorised use. Unlike traditional film-based images, original digital files are no different from their copies, so any duplication is as high in quality as the original it was made from
(Mitchell, 1992). Since most copyright infringement stems from a misunderstanding of copyright law (Pickerell and Child, 1994),
the Picture Agency Council of America has produced a set of Copyright Commandments in an attempt to prevent misconceptions of what constitutes legal use. To make unauthorized use more difficult, several digital copyright protection techniques have been introduced:
- Encryption: Two different companies,
Digimarc Corporation and
have recently developed separate "fingerprinting" technologies that embed virtually unremovable identification information into the pixels of graphic image files. Although invisible to the naked eye, this information can be decoded and viewed through the use of free Adobe Photoshop®
plug-in for both Windows and Macintosh platforms.
- Low Resolution Distribution: So far, some distributors of digital imagery have attempted to protect their copyrighted images by restricting the viewing resolution of each image to a 'thumbnail' size, or a size that is just large enough to be reviewed on a computer screen. In many cases, photo-buyers may not feel thumbnail images offer them enough information to determine whether the image is suitable for their needs.
- Watermarks: A fairly recently developed method of protecting digital copyrights has surfaced with the use of semi-transparent watermarks
superimposed on top of digital images. Unlike other forms of copyright protection, watermarks prevent the theft of images by hampering the copying or stealing of the image right off a computer screen. Although this method is not considered completely foolproof, the time and expense required in removing the watermark would theoretically cost more than the licensing fees associated with legally using the photograph (Stone, 1993). Stock photography libraries have
welcomed the idea of using semi-transparent versions of their company logos over their digital images as a way of allowing both copyright protection and the immediate recognition of their name (Senft, 1993).
Some art buyers, on the other hand, have complained about not being able to get a clear view of the obstructed images (Pickerell and Child, 1994).