for use by future generations. The Library of Congress has carried out its preservation responsibilities using a variety of professionally accepted practices:

  • Providing adequate storage conditions (e.g., proper environmental controls and appropriate binding and shelving);

  • Reformatting materials from their original fragile formats and media to more stable media (e.g., microfilming newspapers and brittle books, transferring audio recordings to more stable media, and copying content on nitrate and acetate film to more stable polyester film bases); and

  • For a small percentage of rare and unique materials with intrinsic value in their original formats, restoring originals through conservation treatments.

The Library also has a long history of providing leadership in the broader field of preservation. Over the last two centuries, it has conducted research and led efforts in areas such as binding and shelving books, proper environmental conditions for storage, use of microfilm for preservation, and mass deacidification of paper. The Library has also contributed to national preservation efforts, such as the development and adoption by many publishers of a standard for permanent paper and the coordination of preservation efforts under the Brittle Books Program, funded by the National Endowment for the Humanities, and the National Newspaper Project.1


The Library faces challenges in digital preservation that are widely recognized and shared by many other libraries and archives. They include the following:

  • Fragile storage media—Digital materials are especially vulnerable to loss and destruction because they are stored on fragile magnetic and optical media that deteriorate rapidly and that can fail suddenly from exposure to heat, humidity, airborne contaminants, faulty reading and writing devices, human error, and even sabotage.

  • Technology obsolescence—Digital materials become unreadable and inaccessible if the playback devices necessary to retrieve information from


For additional information on LC’s preservation efforts for analog materials, see <>.

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