Columbia University Libraries is strongly committed to the preservation of its books and journals, so that it can continue to provide access to a useful scholarly research collection for the Columbia University community. While it is our good fortune to have such a distinguished, in-depth retrospective collection, it is also true that many of these valuable, often irreplaceable materials are deteriorating on our shelves.
It is well known that from the early 1800s paper was increasingly manufactured through processes that leave an acidic content. The acid gradually breaks down the cellulose fibers of which paper is composed. With sufficient time, especially in conditions of high humidity, high temperature, and polluted air, the paper becomes so brittle that it breaks when folded. We in New York City are particularly unfortunate in our environment, and our collections have suffered more than those in many other parts of the country. Happily, most North American and Western European scholarly volumes are now printed on acid-free paper with a much longer life than the acidic paper to which we are unfortunately accustomed, but large portions of the collections printed on acidic paper constitute a legacy that must be preserved.
Over the past twenty-five years research and academic librarians have worked with conservators, scientists, and micrographics experts on technologies to address these problems. At the same time they have developed policies and principles to guide the application of these technologies. No one technology solves all problems. Libraries like Columbia have adopted a comprehensive approach which carefully matches the appropriate treatment to the damaged book.
The preservation of embrittled materials poses a significant challenge because paper that breaks when folded cannot withstand the manipulation needed for rebinding or repair. This means that a book whose pages have begun to break cannot be put back together again except by extremely costly page-by-page conservation treatment – and this is not always possible. The monetary value of most volumes in the Columbia University collections does not justify spending hundreds of dollars per volume for repair, although we do have rare materials for which such costly conservation is fully warranted.
For most books that are too brittle to be repaired with routine methods, the most appropriate preservation technique is to purchase a reprint or, if none is available, to turn to reformatting create a copy of the text of the volume (its "intellectual content") if not its physical manifestation. The new copy is then properly housed and cared for to ensure its longevity.
As for the brittle volumes themselves, the policy of the Libraries mandates that volumes be reformatted intact whenever possible, so that they may be returned to the shelf for whatever further use they can sustain before finally disintegrating. A volume with a significant binding may be placed in a custom-fitted box for additional protection. If a volume's pages are in pieces before it is reformatted, however, it is already beyond further use and may be withdrawn from the collections once a copy is made.
Three technologies are used for reformatting: microfilming, photocopying, and digitization. Microfilm provides the greatest security for the future, since the master negative of the film is stored under archival conditions to assure a lifespan of several hundred years for the content of the volume, and new positive copies can be produced on demand.
Preservation photocopies are made with acid-free paper that can last at least a century. Unlike preservation microfilm, however, preservation photocopying creates only one copy. There is no a master to be archivally stored for hundreds of years and used to produce a new copy if the first is damaged or destroyed.
Digital imaging is the newest reformatting technology, and when it is combined with optical character recognition it brings with it useful capacities for full-text searching and manipulation that neither film nor photocopies can offer. On the other hand, digital files are quite unstable. Assuring longevity for a book in digital form requires a complex infrastructure for long-term digital archiving and format migration, many of whose aspects are still evolving. Digitizing is thus, at present, the most risky and the most costly reformatting option.
Columbia University Libraries employs the three techologies where each is most appropriate. We are also committed to continuous development of our long-term digitial archiving capacity, in order to enable expanded use of digital conversion. The decision on how to preserve each brittle, unrepairable volume is made by the bibliographer responsible for its subject area, in consultation with staff from the Libraries' Preservation Division. When appropriate, the bibliographer also consults with relevant faculty members. Every effort is made to ensure that the most suitable preservation method is applied. In general this means that the preferred treatment for any damaged volume is rebinding or repair. When a volume is structurally unsound and too brittle to repair, the Libraries will try to locate a non-brittle paper copy, reprint, later edition, or secure access to an online version. Reformatting is normally the last alternative.
Identification of brittle volumes involves library staff, faculty, and other library patrons. Public service staff of all the Columbia libraries screen volumes returned by patrons to find endangered items. Library patrons who use damaged volumes bring them to the attention of the library staff. Concerned faculty are encouraged to discuss endangered parts of the collections with librarians. When special grant funding is available, librarians work with the faculty to identify areas of particular importance for concentrated preservation activity, and collaborate with existing or specially-created faculty advisory groups on large preservation projects. The amount of preservation work needed by the collections is great, and requires participation from all of the Columbia community.