The Preservation Directorate of the Library of Congress investigated the viability of a preservation program that addresses the condition of those objects that are currently “too brittle to serve.” The extreme fragile condition of these objects does not only exclude them from being served but often even from being reformatted. The Library contains many collections of this type of material and the large quantities of objects they contain preclude them from being treated through costly single-item treatment. The goal of this program is, therefore, to find and evaluate a cost-effective treatment protocol that can handle these items in bulk.
The most effective technique to increase the physical strength of paper, and significantly slow down the chemical degradation, is the mechanized version of a process called “paper splitting.” In this process the brittle paper sheet is “sandwiched” by temporarily adhering two support papers, one on each side. Pulling apart the support papers splits the original paper. A new “core” paper can now be inserted between the original paper halves and the entire package is reassembled. The support layers can be removed in an enzyme bath and the original paper and inserted core paper are pressed and dried. Since washing and deacidification of the original paper is an integral part of the process, both the physical and chemical condition of the paper is improved.
The three-member project research team consists of a book conservator, a paper conservator and a conservation scientist. The team is mainly responsible for evaluating paper strengthening techniques, selecting objects to be treated, and examining and analyzing treated objects. An advisory committee was established at the start of the program to provide guidance and advice. The committee consists of five well-experienced preservation specialists from various research institutions and libraries, and advises on selection criteria, treatment evaluation and potential future collaborative projects. The committee affirmed the promise of paper splitting for various brittle materials and saw an important role for this technique in strengthening 19th century woodpulp paper.
ZFB (the Zentrum für Bucherhaltung) in Leipzig, Germany, is currently the only company that provides mechanical paper splitting services on a commercial basis. The Conservation Division and the Research and Testing Division jointly conducted the evaluation of a large number of samples that were treated by ZFB. In addition, the program research team has compared multiple treatment procedures and optimized the final treatment protocol. Treated samples have been aged artificially in the Research and Testing Division and the results clearly demonstrate the benefits of mechanical paper splitting. The efficacy of the process can be determined by the higher brightness, pH and tensile strength of the treated samples versus the untreated counterparts.
The first two slides show untreated newspaper samples; the last two slides show treated samples. The first and third samples are not aged, while samples two and four have been aged artificially using elevated temperatures. Here one can see that the fourth sample fares much better than the second untreated) sample.
Treatment of the New York Journal
The first collection to be treated as part of this pilot program is the bound volumes of the New York Journal from 1896 to 1899. The paper in these bound newspaper volumes was in extremely poor condition. The poor paper condition did not allow for any use for fear that it would cause further damage. The NY Journal from this time period also contains a high volume of image material. Graphics translate poorly into microfilm, which was further incentive to treat the NY Journal from this time period. And finally, the NY Journal was one of the William Randolph Hearst papers and original issues are becoming increasingly rare and therefore important to preserve.
Prior to treatment the volumes were stored in acid-free boxes and off-limits to library patrons and scholars.
The Library has awarded ZFB a contract for the treatment of 17,500 newspaper pages and the rebinding of the newspaper volumes. At this point 1,500 sheets have been treated, and circa 10,000 sheets are currently in process. Initial examination of the treated volumes shows excellent results. The papers have regained flexibility, can be handled without causing damage, and can be consulted easily because of the new post-binding structure. This binding structure also allows for temporary removal of one or more sheets for exhibition purposes. Additional objects that have been selected for testing include rotogravures, pulp fiction volumes, type written manuscripts, and sheet music. Library staff is actively engaged with the selection and testing of additional material.
The newly treated volume is on the right. Each sheet has been washed, leaf-cast, split and rebound.
For further information on paper splitting:
Dambrogio, J. and I. Bruckle. "Paper Splitting: A Paper Strengthening Process. (Abstract)" Book and Paper Group Annual 19 (2000).