Johns Hopkins Gazette: February 10, 1997

APL, MSEL Rescue
Peabody Books

Ben Walker
Applied Physics Laboratory

Next to fire, water is a book's worst natural enemy. Water swells books, breaks their spines, dissolves the ink, turns them black with mold and glues pages together so they can't be read.

So, two years ago, when water from a faulty air-conditioning system at the George Peabody Library drenched nearly 1,800 out-of-print and irreplaceable 19th-century books, the Peabody community was understandably distressed. Fortunately, though, preservation experts at the Milton S. Eisenhower Library on the Homewood campus were ready with a disaster plan.

After toweling off superficially wet books and setting others out to dry, Eisenhower preservationists froze the 276 books that were completely soaked and placed them in commercial cold storage.

Then they called APL for help.

"Our thermal-vacuum chamber is ideal for freeze-drying materials such as books," says Bill Wilkinson, a space simulation engineer in the Space Department.

Vacuum freeze-drying is an effective technique for restoring frozen books because during the process the ice sublimates, that is, it changes directly into a vapor without passing through a liquid phase, thus preventing any further water damage.

But the technique was more of an art than a science at APL before Wilkinson conducted several preliminary tests to find the best approach. In one test, he soaked an old airline guide--the six-pound book absorbed nine pounds (over one gallon) of water-- and then flash-froze the book and inserted probes to monitor temperature. He placed it in the thermal-vacuum chamber at a reduced atmospheric pressure of less than 0.1 psia (normal atmospheric pressure is 14.7 psia). The book dried in three days and could be read page by page.

"That's the goal--to open every page without sticking or tearing and then be able to read the original printing," says Wilkinson. "We're not trying to return books to their original condition in just one step. The excellent Preservation Department at Eisenhower will complete the restoration process."

To prevent water vapor from damaging the chamber's vacuum pumps during the process, Wilkinson called on the APL Technical Services Department. Using materials paid for by the Eisenhower Library, a Plant Services team of Keith Bush, Lee Thompson and David Richmond built a six-foot-tall liquid nitrogen trap to capture the large volume of extracted water before it gets to the pumps. Wilkinson says it's a permanent addition to the thermal-vacuum chamber that enhances its capabilities, adding that the chamber will be used for book restoration projects only on a non-interfering basis with normal test operations.

Work on space programs, notably NEAR and ACE, delayed use of the chamber for the Peabody books until last October, when Martha Jackson of the Eisenhower Library selected 15 frozen volumes in various states of damage for an initial test. The oldest book, Sheridans Dictionary (English), was published in 1789. After two weeks of drying, every page of every book in the test group was readable.

"It's the result we were hoping for," says Jeanne Drewes, head of the Preservation Department in the Eisenhower Library, which includes the Peabody Library. Drewes inspected APL facilities in December along with Maria Skepastianou, a preservationist from Ionian University in Corfu, Greece, on a visit arranged by Wilda Newman of the Administrative Services Department.

Newman says that today's preservationists are also concerned with electronically stored digital information held in "virtual" libraries. As members of the International Federation of Library Institutions and Associations, Newman, Drewes and Skepastianou are all involved in extending disaster planning to include such data. In this connection, Wilkinson says that freeze-drying also works on computer floppy disks. He recently used the technique to return a water-damaged disk to a usable condition.

Drewes has given APL the go-ahead to restore the remaining 261 Peabody volumes. Wilkinson says the job will start the end of February and take about two weeks. "We're glad to help another member of the Hopkins family," he says.

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