The Preservation Department offers a broad range of services designed to preserve and maintain both general and special collections.
Preservation Department staff rely on a variety of in-house and vendor-based preservation services, including shelf preparation, commercial binding, mass deacidification, microfilming and digitization, to insure that library materials are maintained in the best possible condition.
A well-integrated program of shelf preparation represents one of the most cost-effective means of maintaining the long-term health of collections. By insuring that items are added to the collection in good condition and taking care of small problems before they become major liabilities, the Preservation Department works to minimize the long-term costs associated with preserving large research collections.
All items added to the genaral collection, including new purchases as well as gift books and historical collections of older material, are reviewed by Preservation Department staff. Items are assessed for their ability to withstand normal use and circulation: applying a set of established guidelines, staff determine which items require binding, repair or other treatment (such as the addition of a pocket for loose materials or the tipping in of an errata) before applying a call number, bookplate and property stamp to each item.
The Preservation Department binds over 25,000 volumes each year. This includes the binding of new library materials such as complete volumes of periodicals as well as the permanent binding of paperback monographs. High use items from the general collection, which may become damaged as a result of frequent circulation, are also sent to the commercial bindery.
The Preservation Department works closely with The HF Group  to ensure that volumes are bound within current preservation standards. Upon return from the commercial binder each volume is checked for quality control.
Paper-based collections in the nation's libraries and archives are being threatened by acid contained in the very paper on which they are printed. No fire, flood, tornado or earthquake will ever cause as much damage to the Library collections as these harmful acids. In years past, libraries have chosen to microfilm, photocopy, and create digital surrogates to take the place of items already too brittle for patrons to use.
Mass deacidification is a chemical process that neutralizes acid in paper and deposits a chemical buffer to prevent further acidification, thereby preventing the materials from becoming brittle. The Preservation Department deacidifies several thousand items annually.
The vendor the Preservation Department currently uses is Preservation Technologies Inc.  and the deacidification process is called Bookkeeper.
The use of microfilm as a preservation option has declined significantly in recent years.
The Preservation Department uses the process of microfilming to prerserve two publications: The Daily Northwestern and Vanguard, a Nigerian newspaper collected by the Herskovits Library of African Studies. Backstage Library Works  is our current vendor for microfilming services.
Items from the general collection that are too deteriorated to be used or repaired are reviewed for replacement, digitization or withdrawal from the collection. Preservation Department staff search each title to determine the status of current holdings, the availability of reprints and the cost of digitization and then recommend the best preservation option. These recommendations are reviewed in quarterly meetings with each selector to determine the most appropriate course of action.
Assuming that the book has not already been digitized and archived in HathiTrust , digitization is often the best option for preserving content. Items selected for digitization are sent to the Digital Collections Department for in-house digitization or to Acme Bookbinding  for vendor-based digitization.