The Abbey Newsletter

Volume 14, Number 6
Oct 1990

Deacidification vs Microfilming

by Ellen McCrady

All methods of preservation (with the exception of collection-wide protective measures like security systems, pest control and regulation of light levels) are complimentary, in the sense that they do not work to preserve a collection unless they are used together, to provide a full range of treatment options for each item in the collection.1 No single method can be used indiscriminately on all books, because this may result in no preservation effect at all, or even in actual destruction. Although few librarians would disagree with this, libraries have historically had a tendency to overapply whatever method they have the facilities and routines for doing easily. It seems that the pressure to "do something" for the books is stronger than the pressure to sort then out or select them for treatment according to what each one needs. Brittle books have been rebound when they should have been microfilmed, and in libraries where the "clean sweep" or "vacuum cleaner" method of selection for microfilming is used, books get microfilmed that should, for various reasons, be rebound, boxed, photocopied, encapsulated or simply left alone. Other examples of inappropriate wholesale treatment could be mentioned.

This pressure to take some kind of action, whether appropriate or not, may have eased up a bit in recent years. "Phased conservation," a sort of creative postponement used by book conservators, has provided a model for librarians. It involves decisions based on three factors: 1) presently available treatment methods and preventive measures, and their costs, 2) better methods that may not be available (or needed, or affordable) until some time in the future, and 3) interim or stopgap methods that enable an item to survive until the future treatment becomes possible and necessary. Conscious choice of the best measure for the particular case is an important part of phased conservation, and that choice frequently calls for the decision-maker to weigh the relative benefits of present and future action. Mass deacidification is not normally thought of as a phased conservation measure, but if its benefits are weighed against those of microfilming, then one can say that a comparison of present and future action is being made, which is very similar to phased conservation. Deacidification of a book that is acidic but not yet brittle postpones the date of eventual microfilming (or of eventual re-deacidification!); failure to deacidify it before it becomes brittle makes microfilming more likely, eventually. In this sense they are alternative choices.

Deacidification & Microfilming as They Relate to the "National Collection'

A new element in the picture complicates the choice between microfilming and other methods of preservation, including deacidification. This is the concept of the "national collection." No research library today can serve its readers' needs without help from other libraries. Purchases of new books are being made cooperatively; that is, libraries are specializing, because they cannot afford to collect everything any more, and in any case, they can always borrow from each other. So each library can be thought of as owning a part of the nation's "supercollection."

When it comes to Microfilming, there is a consciousness now that it serves the national collection as well as local needs. A master microfilm is produced from which copies can be made as needed, not only for the library that owns the film but for any library that wants to order a copy. In essence, microfilming is a potential reprinting operation: as many copies as desired can be made from the printing master, on demand.

Mass deacidification theoretically does not help to build the "national collection" because it does not produce an identifiable master, but indirectly it facilitates use of the original as a master by maintaining its strength and prolonging its life. Anyone who has fought crowds in a copy center can testify that originals are used as masters nowadays. Although most of the photocopies see only temporary use and do not wind up in a cataloged collection accessible to the public, photocopying is done on such a large scale that its influence an our storehouse of knowledge cannot be ignored. It has become an element in the whole educational and research process, and its success depends partly on the ability of the books to withstand the copying process. So in this sense deacidification would help to maintain the national collection.

This supercollection, like ordinary collections, has a lending program. As more and more libraries decide not to buy a book because other libraries have that title, the average library book becomes scarcer and scarcer. Readers across the country are swamping interlibrary loan offices with requests for books in other libraries. Like photocopying, lending is hard on a book's binding and pages, and is usually not permitted for very brittle books. So deacidification would also help maintain the national collection by keeping books strong enough to lend to other libraries.

Relative Merits of Deacidification and Microfilming

The relative advantages of these two methods cannot be easily summarized. Microfilming creates a master but deacidification preserves the original in usable condition. Deacidification is more of a gamble than microfilming, because the most promising methods are not available commercially and there are no standards yet for it as there are for microfilming (though this situation is bound to change). Is it possible to calculate, for policy purposes, how many copies of a deacidified book would be equivalent to a single microfilm copy and its copies, in term of benefit to research and education Factors to take into account would include:

1) Cost. Microfilming now costs about 10 times as much as deacidification will cost, when it becomes generally available. There will never be enough money to do all the books by either method.

2) Obsolescence vs. enduring value. As time goes on, it may be easier to decide which books to microfilm because the more valuable ones will have had a chance to prove their worth. So fewer books may need microfilming than deacidification in the end, because deacidification has to be done at an earlier stage, when less is known about a book's eventual worth.

3) The usefulness of the format for scholars and students. How much would the microfilm copies actually be used? A 1985 survey in England found that microfilm was underused. How much use are today's microfilm masters seeing in the U.S.? The Commission on Preservation and Access recently found that microfilm copies are sometimes hard to locate and hard to obtain.2 How likely is it that a student or similar would order a microfilm copy of a book if the library did Mt already have one? How important is browsing in the stacks for the advancement of knowledge, in the long run?

4) The relative value of an original and a copy. For some books and some researchers, a copy is not acceptable because it does not transmit crucial information found in the original.

5) Security. How likely is it that the microfilm master could be lost, deteriorated or destroyed before its useful life is over, 500 or more years from now? There is a relative security in having multiple copies in different libraries. There have been few 500-year periods in the history of any country without wars, natural disasters or major disruption of social, economic and political system. Such disruptions have always been hard on library collections. It is often the remote, inconspicuous collections that come through unscathed, while central -repositories a-re plundered or destroyed.

6) Practicality of monitoring in a national database the preservation actions taken by the various libraries. (Treatment of an individual title would probably be carried out regardless of what other libraries are doing, while duplication of another library's microfilming work would be avoided if possible.)

Do We Have to Decide Which Method is Best?

As far as the individual library is concerned, the choice is easy. If a given book is acidic but strong, and likely to be of enduring value, it is a candidate for deacidification. If it is brittle, and likely to be of Enduring value, it is a candidate for microfilming. Both options should be open, and neither should be overused. Since there will always be more candidates of both sorts than any library can handle, some kind of conscious balance should be sought, to avoid giving inappropriate treatments in a one-size-fits-all program.

On a national scale, and in the long run, a similar balance must be struck, not only between deacidification and microfilming, but among all forms of preservations.3 The availability of generous federal funding for microfilming, but not for other preservation options, should not be allowed to affect the quality of preservation decisions for individual copies of books. They have an increasingly important role to play in this age of cooperation. Individual books as well as microfilm masters should be seen as resources that belong, in a way, to all libraries. We should do what we can to assure that the most appropriate method of preservation is used for each one.


1. This editorial point of view was expressed earlier by the author in her review of Brittle Books (Commission on Preservation and Access, 1986) in the Abbey Newsletter for October 1986, p.79, and also in reply to Robert P. Markham's letter to the Editor in the Abbey Newsletter for December 1986, p. 94.

2. Low usage of U.S. microfilms was documented in an informal survey of 13 institutions, reported in the July 1990 issue of the Commission's newsletter, and summarized on p. 69 in the July Abbey Newsletter.

3. Joseph Rosenthal raised this question at a spring 1990 ARL meeting, which was reported in the Commission on Preservation and Access Newsletter, July 1990, p.4.

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