The University Record, September 10, 1997
Conservation assistant Tom Hogarth and Shannon Zachary preserve a map with the Minter Welder. Photo by Bob Kalmbach
Whether it's a map, Brahms' sheet music or an underground press pamphlet, the University Library's Conservation and Book Repair facility can preserve and protect it.
Between 1860 and 1960, and still in many parts of the world, ground wood pulp has been used to make paper, says conservation librarian Shannon Zachary. Even after a few years, this paper becomes brown and brittle to handle, a condition afflicting millions of pages in the University Library holdings. "Human use is the most destructive element to a book," Zachary says. "But the books and materials at the U-M are here to be used. A research collection has to be used."
A generous donation has allowed the conservation facility to purchase a Minter Welder, a sophisticated machine that allows a page to be encapsulated in polyester film, a stable, non-acid substance. By using concentrated ultrasonic vibrations, the molecules in the polyester become "excited" and create heat that seals only along a narrow line. There is no excess air caught between the polyester film, no bulking up, no distortion. Storage space is just slightly more than before the process. And there is no adhesive applied to the document, Zachary says.
What was a brittle page, breaking into pieces at the slightest touch, becomes pliable once encapsulated in the polyester film. No white gloves are needed to handle the material. A clear photo copy can be made of the material without removing it from the film.
"This machine deals with a problem that was difficult to solve in any other way," Zachary says. "While many books can be copied or microfilmed to preserve them, some documents must be saved as originals."
The welder can accommodate any size page. Recently a page from a 1942 edition of the New York Times was preserved with the welder. Maps from the University Library's Map Room and sheet music from the Library's Special Collections have been preserved with this process.
With the purchase of the welder, U-M's conservation facility joins the Library of Congress, the New York Public Library and several other university libraries with this preservation capability.