Mass Deacidification in the Library: A Rare Book Librarian Considers Bookkeeper

Charlotte Tancin, M.L.S.

This report includes a rare book librarian's observations on the issues of handling and logistics, as well as on observed side effects which may suggest guidelines for selection of library materials for mass deacidification. As with any mass treatment process, Bookkeeper is recommended for circulating and research collections rather than for rare book and other special collections. Although only bound, published material was treated and evaluated in these tests, the Technical Evaluation Team recognized that archival collections would also benefit from the development of a reliable mass deacidification process. Twenty-five treated items were subjected to empirical testing for the presence of visual, tactile, and olfactory side effects resulting from processing by Bookkeeper. A checklist was developed and used for the evaluation. Many of the negative side effects seen with other treatments are not in evidence with the Bookkeeper process. Empirical Evaluation

Beyond determining what the Bookkeeper process does to benefit paper--how, whether, and how well the treatment works according to Library specifications--the Technical Evaluation Team also tried to ascertain what the process does to paper (as well as to ink, adhesive, cover material, and other book components) and whether any discernible changes resulted. In particular, the Team wanted to respond to the concerns of the preservation and conservation fields related to specific undesirable side effects. Empirical tests were added so that Team members could look for potential problems in a variety of typical library materials.

In addition to the testing done by the Institute of Paper Science and Technology on the LC blue test books fabricated and supplied by the Library of Congress, empirical tests were also performed by the Team on another, supplemental test batch of twenty-five items which were collected from local libraries. Each of the items was cut in half. One half was treated and the other half retained as a control. The twenty-five treated halves were not subjected to laboratory testing, but instead were examined by Team members who compared them with the control halves for perceptible side effects such as color changes, physical deterioration, odor, and surface deposits. This small sample, which was representative rather than comprehensive, included materials typically found in circulating and research collections.


In most cases, few perceptible side effects on treated material were observed. Test items sometimes emerged from treatment cleaner than the corresponding untreated halves. No odor was perceived after the treatment. In fact, in some cases, a musty smell, obvious in the control half, was removed by the treatment. The clamps used to hold test materials in the August 1993 tests left impressions on the covers of some of the books.

There was a chalky deposit, visible or, more commonly, palpable, observed in several cases. No color change resulted from treatment, except in the case of a pH sensitive marker, and no feathering of inks or pigments was observed. When illustrations on coated paper were rubbed with cotton balls, slight rub-off was observed in some cases. This ink did not come off on fingers, nor did it offset onto facing pages.

No effect on the call number labels and bar codes affixed to book covers in the selected library test batch was noted. There was no blistering, lift-off, or damage. This is good news from the point of view of posttreatment library processing. Treated books displayed no color change on their covers or damage to adhesives.

Following treatment, the test books exhibited no evidence of blocking, sticking, swelling, cockling, or any other distortion which would make the treatment less acceptable to librarians. From the empirical perspective, Bookkeeper is in many ways an attractive process because it eliminates undesirable side effects. Selection

Once the efficacy of the Bookkeeper process and its relatively benign nature have been determined through laboratory and empirical testing, it is important to consider what type of collection materials are appropriate to select for mass deacidification. The potential effects of the mechanics of the treatment process on the material, as well as the effects and side effects of the deacidification process itself are factors in this decision-making. As with any mass deacidification process, the items chosen for treatment should be limited to mainstream research or circulating collection materials. These collections, determined to be of long-term value, are good candidates for treatment before they become brittle. Many archival collections may also be appropriate for mass deacidification. However, archival materials were not tested as part of this project. Interested members of the archival community may wish to be involved in future testing.

Faced with difficult questions such as whether to concentrate on deacidifying new acquisitions or rather on those books already at risk, librarians will need to set priorities carefully based on local collection risk and use. The simplest and ideal solution would be to mass deacidify entire collections with no preselection, except perhaps for those items obviously too fragile or deteriorated to treat. Librarians should assume the presence of materials in every collection which are not appropriate for treatment. Few libraries, of course, except the Library of Congress, have the financial resources to contemplate treatment of entire collections. The rest of us will be faced with the need to set priorities among our collections.

The establishment of local guidelines will make possible the identification of materials appropriate for mass deacidification as well as of those items which should never be treated. Because there are a number of idiosyncratic issues relevant to preselection decision-making, some libraries will have few items to be deacidified, while others may invest significant time in establishing procedures to exclude materials from mass deacidification.


Special collections in general should not be treated in a mass process. Although little damage to materials was observed in these tests, special collections and rare, unique, or exceedingly valuable items should be assessed individually by a conservator who will be aware of potential effects of deacidification and handling as well as the special needs of those materials. The conservator can then make recommendations or perform treatments as appropriate. Items having artifactual value (that is, they have value as objects beyond their information content), warrant extra care in handling. The library's guidelines for preselection must reflect these issues. Brittle Paper Because no deacidification process can restore brittle paper, books whose paper is already embrittled are inappropriate for mass treatment. If items are fragile or deteriorated to the extent that handling would harm them, they, also, should not be sent for mass treatment.

Working with the Vendor

The librarian contemplating mass treatment will want to establish a dialogue with the vendor. Through this communication with prospective clients, the vendor can contribute to the development of selection guidelines and of a framework within which to discuss the special needs and concerns of the library. Mutual understanding will simplify procedures for both the vendor and the customer. For example, because of the necessary unpacking and repacking of books from the boxes which are used to transport the materials to and from the treatment facility, guidelines should be developed for packing and shipping. Librarians will want to ensure that there will be specifications for appropriate care and handling of the materials at the treatment facility.

PTI may wish to consider consulting with preservation experts to develop selection guidelines for treatment and for handling of materials sent for treatment once the process has been scaled up. The guidelines would address routing and handling of materials through the physical plant, the mechanical process, treatment work flow, and other issues. Such guidelines will be useful to customers who are choosing and sending collection items for treatment. They would also assist PTI staff in making decisions about items submitted for treatment which may be too fragile or damaged to treat.

Some potential issues were not addressed in the course of the testing, but could easily be explored. The physical process of immersion and mild, continuous agitation which characterizes the Bookkeeper process could dislodge or damage loose sheets or other material during treatment. However, no floating loose pages, unfolded maps, or damage to mounted plates were observed during the processing of the test batch. Only a few mounted plates and folded maps were included in the test batch. Evaluation after treatment of folded paper charts and maps in book pockets or of mounted plates and maps will indicate whether there is any damage or problem related to complete treatment. None of the test books had pockets containing supplementary material in nonpaper formats such as microfiche, plastic overlays, or computer disks, but the growing presence of these formats presents yet another challenge. In some library collections such supplementary material is stored separately, while in others it is left in the pockets in which it was originally contained. Although not of primary importance to all collections, it will be a matter of interest for some librarians. Guidelines for treatment and handling will help highlight potentially problematic areas and create awareness for new users.


In addition to the mechanics of the treatment process, the logistics of the Bookkeeper process are of interest to librarians. Books to be treated would be unpacked from the boxes they were shipped in, opened and individually fastened to the racks for treatment, removed from the racks after being treated and dried, and repacked for return shipment. This handling should present no problem for books in good condition from circulating and general research collections, and, in fact, would probably produce no more stress on such books than they would sustain through normal use, circulation, photocopying, and interlibrary loan.

In August 1993, the PTI personnel involved in the treatment exhibited care in the handling of the test materials. However, as the process is scaled up, training for PTI staff will become increasingly important. Training would introduce the staff to the appropriate handling of library materials, according to preservation standards. This will enable them to recognize preservation concerns which might arise in the wide range of materials that make up typical library collections. By making available staff training, seeking advice, and/or adding persons with appropriate knowledge and training to the treatment staff, PTI can minimize potential damage to the materials and alleviate any concerns of librarians.

One further matter of logistics should be mentioned. Librarians opting for mass treatment should be prepared to monitor the pH of their collections after treatment just as they monitor the results of other preservation activities. Pretreatment pH testing by the library is recommended not only to determine how much of the collection warrants treatment, but also to provide a baseline of information against which to assess and monitor treatment efficacy. After treatment, an ongoing program of random retesting is recommended to check treatment results and to monitor pH. And, as with all such collection assessments, keeping statistics is recommended to make sense of the data as well as to exploit fully its usefulness.


In conclusion, aside from the few effects noted in this report, little physical change in treated items was observed, making the Bookkeeper process a good potential option for deacidifying mainstream circulating and research collections. As noted above, rare books and special collections should be considered separately because the librarian must consider how treatment could affect value. The safest approach is the individual treatment of any items of artifactual value which warrant deacidification.

Books are such complex, composite objects that it would be difficult to ascertain in advance and guarantee with absolute certainty that a given book will sustain no undesirable effects from mass treatment. One can, however, get a feel for the odds, weighing positive results against potential side effects in order to make a decision. Based on examination of the limited test materials treated in August 1993, it seems likely that library materials of the type included in the test batch will sustain no damage.

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