Volume 19, Number 6
Nov 1992

Selective Mass Deacidification at Harvard

Status Report, October 1992

The Harvard libraries are moving forward with the development of a selective mass (whole-book) deacidification program for acidic library and archival materials following a successful yearlong pilot operational program to select, send, and receive back materials treated at the Akzo Chemicals Inc. deacidification facility in Deer Park, Texas.

Deacidification is one strategy in Harvard's program to address the problem of deteriorating acidic paper. The program includes storing lesser-used materials offsite in the lower temperature environment of the Harvard Depository, and participating in the nationwide brittle books microfilming program administered by the National Endowment for the Humanities. In addition, Harvard expects to use the new digital imaging technology to provide new means of access to and use of research materials at Harvard and elsewhere.

Selection for deacidification at Harvard emphasizes materials in the following categories: materials for which Harvard assumes special responsibility; materials that rely on original format for effective use; materials with graphic or visual images as intellectual content; and research collections that are needed onsite.

Harvard's interest in deacidification at the institutional level was formalized in 1990 with the appointment of a University Library task group. The group was charged to consider the benefits and costs of mass (whole-book) deacidification and recommend a course of action. A subgroup on technology was asked to review deacidification processes, conduct site visits to commercial facilities and recommend a vendor. The subgroup completed its work in fall 1991 and Harvard signed a contract with Akzo Chemicals Inc. to provide deacidification services using the diethyl-zinc gas diffusion process (DEZ) invented by the Library of Congress and developed by LC and Akzo.

The DEZ process chemically treats whole volumes or groups of paper documents to neutralize the acid in the paper and leave an alkaline reserve to buffer against future acid attack from the environment. In the treatment chamber, which will hold approximately 350 books at one time, air and moisture are removed and molecules of the highly volatile DEZ gas are released to penetrate the materials. A post-treatment process helps remove residual odor and restore the natural moisture content of the paper.

The DEZ process is the result of 20 years of research and development by the Library of Congress, including extensive toxicological tests. In addition, Harvard Professor Andrew Barron and postdoctoral Associate Andrew MacInnes of the Chemistry Department collaborated to conduct additional research into the viability of the process using scanning electron microscopy (SEM), Rutherford back-scattering (RBS), and X-ray photoelectron spectroscopy (XPS). Their research demonstrated that the DEZ process uniformly deacidifies fibers all the way through the paper. However, the current DEZ process is less successful in treating coated paper (glossy paper with a kaolin or other coating). DEZ does not penetrate the coating to treat the acidic core of coated paper. Further research is planned by Barron and MacInnes to investigate treatment options for coated paper. A recent survey at Harvard's Loeb Design Library (architecture, landscape design, and urban design and planning) determined that 32% of the monographs and 68% of the periodicals were printed on either all coated or a combination of coated and uncoated paper. Thus, the resolution of the coated paper issue is critical information for both mass deacidification and preservation planning.

Seven Harvard libraries/collections participated in the pilot operational program in fiscal 1991/92. Approximately $65,000 was spent to deacidify materials from the Law School Library, the reference and map collections of Widener Library (humanities and social sciences), Tozzer Library (anthropology), Loeb Music Library, Kummel Library of Geological Sciences, and the Botany Libraries. Altogether, more than 3700 books and 4688 maps were successfully treated. In fiscal 1993, Harvard will expend approximately $110,000 and expand the number of libraries/collections participating in the program. Proportionally this is still a very modest program, as Harvard spends approximately $1 million each year on library binding and another $1 million on microfilming.

A report detailing Harvard's pilot operational program and a copy of the Barron/MacInnes paper can be obtained by contacting the Preservation Office, Harvard University Library, 25 Mt. Auburn St., Cambridge, MA 02138 (617/4958596). Also available is Harvard's "Ten-Year Plan for Preservation and Continued Access to the Collections."