Saving the Written Word: Mass Deacidifcation at the Library of Congress
The Library of Congress, with strong support from the U.S. Congress, has provided leadership in the development and evaluation of mass deacidification processes and their application to valuable book collections and other paper-based items to achieve economies of scale. Through a competitive process, the Library negotiated a second contract for mass deacidification in 1997. The contract was awarded to Preservation Technologies, Limited Partnership (PTLP) of Pennsylvania. The company is providing book preservation services to the Library using the firm's Bookkeeper mass deacidification process. This contract is an outgrowth of an earlier limited production contract that enabled the Library to deacidify books for the first time and to resolve book selection, shipping, and quality control details of the deacidification program.
LC's "One Generation" Mass Deacidification Plan: A New Multi-Year Contract
Congress demonstrated support for the Library's plan to save 8.5 million retrospective and new books over a 30 year period by approving Fiscal Year 2001 funding that is permitting the Library to award a contract to treat 1,000,000 books and at least 5 million manuscript sheets within five years. The Library plans to ramp up from deacidifying 100,000 books in FY2001, increasing the quantity by 50,000 books per year, until it is treating between 250,000 and 300,000 books annually in the 5th and successive years of the 30 Year Plan.
Library "Demonstration Site"
Given the effective operation of its mass deacidification program for books over the past several years, the Library is serving as a demonstration site for managers and technical staffs from other libraries, archives, and cultural institutions. Anyone interested in learning firsthand about administrative and work flow procedures required for mass deacidification programs should contact Kenneth E. Harris, Preservation Projects Director, Preservation Directorate, Library of Congress, LM-G21, Washington, DC 20540-4500. Telephone: (202) 707-1054; Fax: (202) 707-3434; E-mail: khar@loc.gov.
On-site Contract Work in LC Buildings
Under contract terms, the vendor is providing onsite services in Library of Congress buildings. The company's employees select books for treatment, pack and ship volumes to the deacidification plant, and reshelve books following treatment. After training by Library personnel, the contractor's onsite workers are overseen by a company supervisor, and the Library monitors their progress against contract objectives.
Each
book in a collection is individually examined to decide whether it
is a good candidate for deacidification.
Selection Criteria and Procedures
Deacidification treatment is reserved for books that are acidic and at risk of loss if no action it taken. Due to its role as the national library and the official library of the U.S. Congress, the Library is focusing primarily on selection of "Americana" for early treatment under the mass deacidification program, emphasizing the selection of endangered volumes from collections that are central to the Library's mission. Screening and treatment is being undertaken beginning with the following LC book classes, which have been approved for deacidification processing by Library administrators, preservation managers, and the LC Collections Policy Committee:
| Class E | American History |
| Class F1-975 | U.S. Local History |
| Class CS71 | U.S. Family History |
| Classes PZ3&4 | Fiction in English |
| Class PS | American Literature |
| Class JK | U.S. Political Science |
| Class KF | U.S. Federal Law |
| Class PN | Americana Literary History and Collections |
Contractor staff working onsite in LC buildings examine each book in collections that have been designated by Library management for deacidification screening. Overly brittle books are left on the shelf.
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Assessment of paper acidity or alkalinity using a pH pen.
In addition, books with the following characteristics are generally not considered for deacidification treatment with the Bookkeeper process:
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- Text paper is alkaline or permanent (these books are marked with a white dot on the spine, as are books that are deacidified; in both cases, this mark indicates longevity of the text block)
- Text paper is coated or super-calendered (coated paper is not a high priority for deacidification, due to its alkaline coating)
- Title is already available in (or scheduled for) microform or digital format, or it is a candidate for future reformatting due to advanced embrittlement of the paper
- Duplicates of a given imprint of a specific title (only one copy of any given imprint is treated)
Most books that are deacidified under the terms of this contract will be books that are structurally sound enough to be treated in the vertical Bookkeeper treatment cylinders. However, books that have limited binding damage (hinge, joint, head, or tail damage) or are too large for Bookkeeper vertical-cylinder treatment can be deacidified in other ways by the contractor -- horizontally in manuscript-treatment equipment or sprayed.
Volumes with the following characteristics are considered good candidates for mass deacidification in the Bookkeeper vertical book treatment chambers:
Bound Volumes
- Hardbound books generally treat better; however,
- Paperbacks are OK, if they are in good condition and structurally sound (it is critical to determine whether the paper is too brittle to withstand treatment and whether the binding adhesive is too degraded to support the text)
- Plasticized covers will not fully absorb the magnesium oxide and will require wiping off by contractor staff after treatment
Bindings in Good Condition
- No detached covers (boards)
- Leather covers with red rot are OK
- Minor damages (e.g., head cap, head, or tail, as well as minor spine tears and minor hinge or joint damage) are acceptable -- should be noted on packing lists, to prompt additional examination by contractor staff
Books
are mounted in treatment cylinders, where magnesium oxide is deposited
to neutralize acids in the paper.
Text Block in Good Condition
- No loose or torn pages
- Leaves not overly brittle
- No "blocking" (pages stuck together)
Size Parameters
- 11.5" Height x 9" Depth x 2.5" Thickness = maximum measurements for treatment in Bookkeeper III equipment
- Larger and heavier books can be treated in horizontal Bookkeeper equipment or sprayed
Quality Controls
The deacidification process, utilizing magnesium oxide (MgO) to neutralize acid in the paper, takes two hours from the time books are placed in the Bookkeeper treatment cylinders until the volumes are ready to be packed for return to their home library. All steps in the process, from selection to reshelving, are monitored to ensure that the intended results are achieved.
The Bookkeeper process meets the Library's basic preservation requirements by:
- raising the pH level of treated paper to the acceptable range of 6.8 to 10.4 pH
- achieving a minimum alkaline reserve of 1.5%
- extending the useful life of paper (measured by fold endurance after accelerated aging) by over 300%.
Surrogate test papers that are inserted in 10% of the treated batches of books are tested by both LC and the contractor for alkaline reserve in order to avoid the destructive testing (titration) of actual pages from collection books. At LC's request, the contractor also treats one disposable test book per week to confirm that the process is working properly. Test papers and test books are returned each week to LC for additional laboratory testing.
A further quality control check for alkaline reserve in each batch of books (8 per batch) is made by dividing the weight of the batch into the weight of the MgO used to treat it.
All treated books are marked, like the alkaline books left on the shelf during selection screening, with a white dot on the spine. A Bookkeeper label is also attached inside the back cover of each treated book.
Manuscript Deacidification Equipment
| Preservation Technologies has developed new equipment that it is using to offer deacidification services for loose manuscript and archival materials. The Library is negotiating with Preservation Technologies to build and install a horizontal treater and a Bookkeeper spray booth in a Library building on Capitol Hill, which would enable LC to treat on-site paper-based materials in non-book formats, such as manuscripts, maps, music scores, pamphlets, and posters. |  |
| Manuscripts are placed in hanging files to prepare them for treatment. |
Additional Information
More information and data about the Library's mass deacidification program are available at the following web site:
http://www.loc.gov/preserv/pubsdeac.html
At that site, select "Mass Deacidification Program," then scroll to the bottom of the page and click on "Mass Deacidification Publications Online" to access a number of publications about deacidification activities at the Library.