3. The Preserved Copy

This section addresses technologies employed in the preservation process. The first section broadly classifies different kinds of preservation processes. The remaining sections focus on the different technological stages associated with preservation processes dependent upon media conversion technologies. These are: capture technologies, storage technologies, access technologies, distribution technologies, and presentation technologies.

The divisions among these various stages of technology may, at first, seem artificial, particularly to those used to working with paper. For example, we distinguish between the storage medium (3.3.1), the distribution medium (3.5.1), and the presentation medium (3.6.1). In the world of paper, as stated in the Introduction, these are usually all one and the same, even though the same paper book, say, may play different roles at different times. When it is on the library bookshelf, it is a storage medium; when it is being messengered through interlibrary loan, it is the distribution medium; and when it is being read by the patron, it is the presentation medium. In the world of convertible technologies, the separation becomes more than convenient sophistry--it becomes essential, since different media may well be used at any stage of the process. Consider, for example, a table from a scientific journal article (paper: the storage medium), which is FAXed across the nation using a data network (digital electronic: the distribution medium), and printed out directly onto photographic slides (film; the presentation medium) for projection in a lecture.

Indeed, in the preservation milieu, this conceptual separation also offers considerable flexibility. It offers the flexibility of separating the act of preservation itself from the ultimate means of storage and delivery. Thus, for example, microfilming may be used as a preservation process (3.1.4), but the microfilm contents may be printed later onto paper for user presentation purposes. Or the microfilm may be digitally scanned and the contents stored on computer files for subsequent distribution across networks. As another example of this flexibility, images scanned and stored using digital preservation techniques (3.1.5) may later be interpreted using internal character recognition (3.2.5) or page recognition (3.2.6) technologies.

The point is that the ultimate use of the preserved document may not be well- articulated at the time of preservation. Thus, preservation technologies that offer the greatest flexibility are to be preferred to those (such as photocopying (3.1.3)) that offer less flexibility, although lack of funds and patron preference often dictates the use of the latter.

The distinction between the various technology stages is maintained throughout this Glossary.

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