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University of Iowa News Release


Aug. 15, 2007

Photo: Click on the thumbnail photo to download a high resolution version. Susan Hansen, book repair specialist, checks the status of damaged materials being dried out in the University of Iowa Libraries freezer.

UI Libraries Freezer Helps Restore Books

Don't expect to find pints of rocky road or French vanilla when you open the door to the ice cream freezer in the University of Iowa main library. This freezer is filled with water-damaged books and is used to help restore them to the collection where they belong.

In May 2006, the University of Iowa Libraries received the 55-cubic-inch Hussman upright ice cream display freezer. Unlike the average freezer at home, it has a side control panel that allows staff members to regulate the temperature in the freezer to a precise degree.

When books become wet in an accident, freezing them helps deter the growth of mold and is the first step in restoring the books to their previous condition.

"Using the freezer cycle controls, the books are first blast frozen to a temperature between minus 30 and 40 degrees Fahrenheit," says Gary Frost, UI Libraries conservator. "Once the wet books are frozen solid, we proceed to freeze-drying conditions. In this part of the cycle the books are warmed to a point just below freezing. Now the ice in books will 'sublime' as water molecules are scoured away by compartment fans and transported to the colder freezer coils where the ice reforms.

"Periodically the ice on the freezer coils is melted and purged from the freezer during defrost. The books get dryer and dryer as the ice within them disappears. It's actually an exciting science demonstration of the changing vapor pressure of ice at different temperatures."

"Sublime" refers to a process by which ice is vaporized and then immediately condensed again.

The freezer is currently in use salvaging books and magazines from the Geoscience Library where an experiment went awry and water leaked onto books in the room below. The books went into a regular freezer to freeze the water into ice and were then put into the ice cream freezer to rid the books of the ice.

The freezer isn't the only way the UI is working to salvage books from water damage. Frost recently worked with product developer Nicholas Yeager to test a new super-absorbent paper. This paper has a cornstarch-based powder that quickly rids damaged books of water.

The new development was put to the test when the Hardin Library's roof began to leak on some of its journals. Most of the journals had glossy, coated paper, which is usually unsalvageable if water damaged. With the new paper, Frost and the libraries conservation and preservation staff were able to restore the books to their original state.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500

CONTACT: Kristi Bontrager, UI Libraries, 319-335-5960 or or George McCrory, University News Services, 319-384-0012,; Writer, Lindsey Tinnell