Materials such as photographic negatives and transparencies, videotapes, and compact discs (CDs) are frequently found within paper-based cultural collections. It is sometimes assumed that these non-paper-based collections (particularly modern electronic media such as magnetic tapes and/or CDs) are more stable than paper collections, when in fact this is not the case.

This session will focus primarily on the reasons that film-based and electronic media deteriorate. Some related materials, such as glass plate negatives/transparencies and early sound recordings, will also be addressed briefly. You will explore how the interaction among the individual components of each format contributes to deterioration. You will also examine how exposure to external agents of deterioration, such as climate extremes, further accelerates deterioration. This session will continue the process of evaluating the overall condition of your collections and focusing your preservation activities.

If you have not yet reviewed Session 2: Deterioration of Paper Collections of this course, it may be helpful to do so now. An understanding of some of the collection components encountered there (e.g., colorants and photographic emulsions) will be helpful as you move through this session.

Learning Objectives

This session will help you:

• identify the materials and structures that make up film-based and other electronic media commonly found in cultural collections;
• determine why these materials deteriorate, including the interaction of component materials and the role of external factors;
• evaluate the general condition of film-based and electronic media within your collections; and
• identify additional resources to help you learn more about the deterioration of these materials.

As is the case with most paper-based collections, film-based and electronic media are composite structures. To understand the process of deterioration, it is important to be able to identify each component of a particular format. Take a moment to look at the following pictures and name the component materials found in each item. How do you think some of these components might contribute to deterioration?