We use the term "preservation" in a library setting to refer to all the activities that lessen the deterioration of objects over time, enabling us to retain the informational content for as long as it is wanted and, when appropriate, conserve the aesthetic context of the case or cover. We preserve the items we collect, not only because it is incumbent upon us to do so as responsible stewards, but also, pragmatically, so we are not required to spend money to acquire them again. This overview shows how the Middlebury College Libraries work to preserve our valuable shared resources.
Practices as simple as encouraging the careful handling of all materials, and as complex as performing conservation treatments on valuable books, are part of the effort. As the library collection has grown over two centuries, so has the depth of our Preservation Program. From the early years of our library we have endeavored to keep our materials secure on clean shelves, a basic, but important preservation practice. We have also always reinforced materials susceptible to damage, and repaired damaged materials to one degree or another. In the second half of the twentieth century our preservation activities became more consistent and standardized. In the 1970s we significantly increased the number of loose periodical issues bound or microfilmed. In the 1990s an in-house book repair program was created and, recently, we have begun in-house conservation treatments of Special Collections materials. New facilities constructed in recent decades are climate controlled and now all our collections, except the small collection at the Davison Library at Breadloaf, are housed in appropriately controlled environments.
Ginny Faust, Binding & Conservation Technician, busy in the workshop.
ASPECTS OF OUR PRESERVATION PROGRAM
Brittle Books- Perhaps our greatest challenge
This is a "brittle book". (Click on the image to view enlarged version in a new window.) The pages have not been torn, they have been broken. When a book is this brittle, photocopying it just once can result in this kind of damage. Like millions of books published from the 1870s into the 1950s, it was printed on acidic paper made primarily from wood pulp. The paper becomes brittle over time because the pulp fibers are short and do not intertwine to create a strong, flexible paper, and because the acidic chemicals used in the manufacture of the paper break down its constituent elements on a molecular level. This degradation eventually results in the book crumbling and more importantly, the loss of the information contained therein.
Fortunately, environmental-protection laws have restricted the use of many acidic chemicals used in the manufacture of paper, and a side effect of this is that almost all paper manufactured in the United States since the 1960s is not acidic, and is likely to last for hundreds of years. The problem remains however: what to do with deteriorating books already on library shelves? If replacement is not an option, in most cases reformatting the information is the best solution.
REFORMATTING
When the paper in a book becomes so brittle it can no longer be handled without crumbling, there are three options: (1) It can be put aside and rarely used (as would be done when a book's physical properties contribute to its value as an artifact). (2) it can be replaced with a new edition, or (3) it can be reformatted so that the information therein can again be accessed. Paper reformatting options include microfilming, facsimile replacement, and digital file creation. We also reformat old forms of media materials by copying them onto new formats.
MICROFILM AND MICROFICHE
While at first glance they may seem old fashioned and inconvenient, microforms continue to occupy a prominent place in any Preservation Program. Because the technology has been in existence since the 1930s, and national testing and production standards have been in place for decades, preservationists have confidence in the long-term quality and reliability of microforms. Master-negatives kept in cold storage have an expected lifespan of 500+ years, and carefully used copies can last for many decades. Unlike digital files that require "care and feeding" by personnel over time, microform images and viewing technology are static, and therefore very little human interaction is required to maintain microforms. Stability and affordability continue to make microforms a viable option for content preservation.
FACSIMILE REPLACEMENT
A preservation photocopy on permanent paper can be made of the original book. Once bound, the result is basically a facsimile of the original. Costing about 23 cents per page, or about $115.00 for a five hundred-page book, this option is ideal when an easily read copy is required. Digital files of the page scans are often available in addition to the paper copy, and can be added to a digital collection. For an example of this kind of preservation photocopy in our collection, see: Vermont Historical Gazetteer in the Vermont Collection F 46 V51
DIGITAL FILE CREATION
When an original is too damaged or too valuable to be used, a digital file of it can be created both to provide access and, at least to a point, to preserve it for the future. This file can be a text file of the content, an image of the original text, an audio file, or a moving image file. Digitization is still an emerging technology with an uncertain future. Of primary concern is the long-term ability to migrate the files to new formats as they are developed, so the information will continue to be accessible. We have no way of knowing how many hours of staff time may be required to maintain files and we therefore approach the creation of our own digital collections with caution, always retaining the original collections from which the files were created.
We create digital copies of selected Special Collections materials to promote the collections, provide wide access to unique materials, and to protect the originals from handling. To view these collections on the web go to:
http://www.middlebury.edu/academics/lis/lib/library_info/digital/
REINFORCEMENT
When small or flimsy items are added to the collections, the library's Preservation & Processing unit reinforces or repackages them so they can stand up to use and be placed on the shelf.
LIBRARY BINDING
"Library Binding" is the term used for durable bindings meant to withstand heavy use in a shared collection. The Middlebury College libraries have been binding loose copies of periodicals and frequently-used monographs for more than one hundred years. Our Preservation & Processing unit sends shipments to Bridgeport National Bindery (BNB) every two weeks throughout the year. http://www.bnbindery.com/ BNB processes all materials in compliance with the Library Binding Institute's Standard for Library Binding. The Standard was developed in 1923, and refined over the years, by a committee of binders, librarians, and binding materials suppliers to insure consistent quality across the industry. Significant advancements have been made in adhesives, fabrics, and machinery that have resulted in the durable, flexible, and affordable binding we use today. 
Bridgeport National Bindery in Agawam, MA.
The LIS Preservation & Processing Unit offers personal binding services to members of the Middlebury College community. For more information click here.
CONTROLLING THE ENVIRONMENT
An interior climate that is appropriate, stable, and controlled is essential to the preservation of library collections. Heat accelerates the chemical reactions that degrade materials; therefore the temperature should be kept as low as possible while allowing for human comfort. Excessive moisture encourages pests and mold infestations, while extreme dryness breaks down connections between fibers in paper and film. The stability of the environment is also important because fluctuations in temperature and humidity greatly increase paper deterioration. 
The climate control system for the new Main Library maintains a remarkably consistent environment that is constantly monitored by Facilities Services. Readings are taken and tracked throughout the building every thirty minutes. (Click on the image to view an enlarged version in a new window.)
Other aspects of controlling the environment are to keep the library building and its collections clean, to keep pests like insects and rodents out of the library, and to encourage library users to handle materials carefully, especially around food.
REPAIR OF WORN OR DAMAGED BOOKS
The most desired and heavily-used books are more likely to wear out, and therefore are most in need of maintenance. We work to maintain our circulating collection as it wears in order to preserve the content for current and future users. The Preservation & Processing Unit uses acid-free materials and tried-and-true techniques to ensure the long-term stability of the items that are repaired.
Examples: Past and Present
The spine on this book is an example of repairs done in Starr Library in the early part of the 20th century. When proper techniques and quality materials are used, repairs last for many years.
The spine on this book is an example of repairs done in the 1970s. When low-quality materials and techniques are used the repair does not last, and sometimes even damages the item. In this case, the self adhesive book tape has dried out and is falling off the book.
The spine on this book is an example of repairs currently performed using conservation-quality materials and state-of-the-art techniques. A repair of this kind will stand up to regular use for many years. Over the long-term this kind of quality saves money, because the library is not obliged to repair or replace the item repeatedly.
More recent repairs.
(click on images with black borders to see an enlarge version in a new window)
This book from the circulating collection had a worn cover and broken hinges. The old cover was removed, the text block was recased in new materials, and the original spine was salvaged and pasted to the new spine.
The boards and spine on this book had completely separated from the text block, and a few pages were loose.
The loose pages were resewn, the endpapers were repaired and reattached, and the spine was rebacked using a piece of buckram cloth. The original leather spine was mounted onto the buckram.
CONSERVATION OF SPECIAL COLLECTIONS:
When we perform "conservation" treatments on items, we are not only preserving the content therein but also retaining as much of the original material as possible. This is important when working with Special Collections materials because the physical properties of a book add to its value and often provide the researcher with important aesthetic context. All conservation treatments are reversible and minimally invasive.
The leather on this book from Special Collections had split at the hinge but the boards were still attached to the spine by cords and the endpapers in a few places.
The ragged leather was cut away and the boards were reattached using a strip of Japaneses tissue. A strip of Moriki paper was then dyed to cover the tissue and reinforce the head and tail of the spine.
A thin layer of a polymer and wax emulsion was then rubbed on the paper to harden it.
The inner hinge was also reinforced with a thin piece of Japanese tissue.
This book from Special Collections had broken hinges both inside and out, and the spine was loose.
The original cover was removed and rebacked (the old spine was replaced) with book cloth colored to match it. New endpapers and mull were attached to the textblock and the original cover was reattached. The original spine was pasted to the new spine.
BOXING: When the cost of conserving an item is greater than it's value to the collection, placing it in a protective container is good compromise. Pictured below is a box we made for a vellum bound book published in 1650. A box like this will protect the item from the degrading effects of light, dirt, and handling, and will allow it to be safely shelved among other books.
The box is made to perfectly fit the book so that it is fully supported on all sides and will not shift within.
PAPER REPAIR: When paper is damaged by wear or mishandling, we repair it using several techniques. Items from the circulating collections are repaired using high quality pressure sensitive tape made of acid free tissue. Items in special collections are conserved using wheat starch paste and Japanese Tissue.
The photos below show Architectural Drawings of the College's buildings dating to the early 20th century. They were conserved in-house when they were being transferred from the Office of Facilities Services to the College Archives. First, old tape was removed using mechanical methods and some of the paper was cleaned. Then the tears were carefully matched and strips of Japanese tissue were pasted to the back of the drawings. (images with borders will open in a new window)
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