The capture of document images for use in DL's is often
carried out in large-scale batch operations. The operations are almost always
designed narrowly to meet the immediate purpose. For reasons of cost, only
rarely will the documents ever be rescanned. In fact, documents can be damaged
or destroyed in the process, sometimes deliberately, e.g. spines of books cut
off to allow sheet-fed scanning. Even more drastically, many libraries have
discarded large collections of books and documents after they have been
scanned, triggering anguished charges of violations of the public trust.