A last example of an old solution that is being reused against forgery and for copy protection is the catalog of signed images of Claude Gellée of Lorraine (1600–1682), also known as Claude Lorrain. Lorrain’s reputation as a landscape painter was such that he was attracting imitations. So, he introduced a method for protecting his intellectual property nearly 100 years before any relevant law was introduced.3 From some time around 1635 until the end of his life in 1682, Lorrain kept a book that he called the Liber Veritatis. The Liber Veritatis was a collection of drawings in the form of a sketchbook. The book was specially made for him, with a scheme of alternating pages, four blue pages followed by four white, which repeated in this manner and contained around 195 drawings.
Baldinucci (1624?–1696), the second biographer of Lorrain, reported that the purpose in creating the Liber Veritatis was to protect Lorrain against forgery.4 In fact, any comparison between drawings and paintings goes to show that the former were designed to serve as a ‘‘check’’ on the latter and from the Liber any very careful observer could tell whether a given painting was a forgery or not.
Similar techniques are being used today. ImageLock , for instance, keeps a central database of image digests and periodically searches the Web for images having the same digest. Tracking systems based on private watermarks (e.g., ) also require central databases. Unfortunately, apart from the extent of the problem (which is now global) nothing much has changed, since such services still do not provide any proof of infringement. Chapters 5 and 7 will investigate these problems further.|| Some Applications of Information Hiding >>