The beauty of the HyperText Markup Language (HTML) (or the up-and-coming Extensible Markup Language [XML]) lies in the rapid access, painless browsing, and search capabilities within a set of files. The format is more generic than any file except a bare-bones American Standard Code for Information Interchange (ASCII) file. This is a positive aspect indicating that future format migration will be possible. The indication is hopeful, but there is no accompanying written guarantee.
Format migration is one of the necessary components an electronic publishing specialist must take into consideration, because unlike printed documents which have been able to depend on the reliability of printed language to span generations of readers1, electronic files are rapidly outdated by the changes within software and hardware systems.
Use of HTML/XML as an electronic publication tool is not enough, though. It must be supplemented with a supporting library of Acrobat Portable Document Format (PDF) files (see below). When combined, these two modes of publication deliver what readers really need: speed for accessibility and browsing, non-linear presentation of information, search capabilities, and a traditional printed document.
The beauty of a PDF file lies in its ability to:
Because of these characteristics, Acrobat files could support a print-on-demand system for documents, to replace the current system wherein publishers print and distribute books and journals. However, the promise of print-on-demand is not yet fulfilled.
Print-on-demand is often touted as a solution to the high cost of printing traditional documents. In reality it simply shifts the cost for the printing of documents from the publisher to the consumer, or an organization such as a library.
A print-on-demand system has two facets:
A product for archival use would be printed at 2400 dpi on archive-quality coated paper, AND assembled as a case-bound volume, thus meeting the standards of the U.S. Library of Congress and other archival organizations. The life span goal of such a document is 100 years. An individual user, on the other hand, typically has access to a 300 or 600 dpi laser printer that can print a document on one side of the sheet only, and requiring collation for stapling or insertion into a binder. The quality of such documents usually falls far short of archival specifications, though. In some areas local print and copier businesses offer this service by printing supplied electronic files, usually on a laser printer or copier. Some may even have WWW access.
Desktop printers available to most individual users do not yet reproduce images of the quality required by paleontologists, petrologists, and other geologists, but this situation is likely to change within a few years. Considering archival requirements, "photo-quality" printers are becoming available, but are still based on the application of ink (or toner) to a sheet of paper usually in dots or spray, and are thus not capable of reproducing the full white-to-black scale that is found in a photograph. These printers are not designed for speed or mass production. Then again, mass production is usually not an issue in a print-on-demand scenario.
To date, most of the discussion in the work place regarding viewing electronic documents has assumed their being read on computer monitors, or as printouts on paper. A third technology, combining characteristics of both paper copies and reading from a monitor is upon us in the form of the electronic book, or e-book (see the e-Book Network). These devices, approximating in size a single- or double-page book, offer a convenient way to carry about and read electronic documents that have been downloaded from a remote server. Files in both HTML and Acrobat PDF formats will be appropriate for this type of viewing. One type of e-book has the astonishing capacity of half a million pages in color. Thus it could hold a good-sized reference library, with a fraction of the wall space. Further in the future, but presently under development, is a technology where documents are viewed on a kind of electronic paper (see MicroMedia Laboratory, which is a part of the MIT Media Laboratory).