The use of magnetic media to record and store numeric and textual information, sound, motion, and still images has presented librarians and archivists with opportunities and challenges. On the one hand, magnetic media increase the kinds of artifacts and events we can capture and store. On the other hand, their special long-term storage needs are different from traditional library materials, confusing to those in charge of their care, and demanding of resources not always available to libraries and archives. Audio and video collections require specific care and handling to ensure that the recorded information will be preserved. Special storage environments may be required if the recorded information is to be preserved for longer than ten years. For information that must be preserved indefinitely, periodic transcription from old media to new media will be necessary, not only because the media are unstable, but because the recording technology will become obsolete.
1.1 Magnetic Media Compared to Paper and Film
As an information storage medium, magnetic tape is not as stable as film or paper. Properly cared for, film and nonacidic paper can last for centuries, whereas magnetic tape will only last a few decades. Use of magnetic media for storage is further confounded by the prevalence of several formats (e.g., U-matic, VHS, S-VHS, 8mm, and BetaCam for video), media types (iron oxide, chromium dioxide, barium ferrite, metal particulate, and metal evaporated), and by rapid advances in media technology. On the other hand, books have virtually maintained the same format for centuries, have almost exclusively used ink on paper as the information storage medium, and require no special technology to access the recorded information. Likewise, newer microfilm, microfiche, and movie film are known for their stability when kept in proper environments, and viewing formats have not changed significantly over the years. (The breakdown of acetate backing that plagues older film materials is discussed in Section 2.3: Substrate Deformation.) This report will compare care and handling procedures for tapes with procedures for paper and film whenever possible.
1.2 The Scope of the Report
As noted previously, this report is concerned with the proper care and handling of tapes to prevent information loss. Tape recording technology consists of two independent components – the magnetic tape and the recorder. Neither component is designed to last forever. Information recorded on a tape can be lost because of chemical degradation of the tape. However, access to information on a tape can also be lost because the format has become obsolete and a working recorder cannot be located. This document concentrates on preservation of the tape and mentions recorders only when needed to understand the safekeeping of tape. Care, maintenance, and preservation of recorders is beyond the scope of this report.
Likewise, the subject of disaster recovery is beyond the scope of this document. Recovery from a collection-wide disaster is best accomplished with the assistance of an expert in tape degradation, who can examine the whole collection and recommend a recovery procedure that may require special equipment. A few contacts for diagnosing and treating deteriorating tape collections are provided at the end of this document.
The handling practices discussed in this document are applicable to all audio and videotape collections-those accessed daily and those stored in an archive. If a particular recommendation is appropriate for only one type of storage, it will be indicated as such. Otherwise, it can be assumed that the recommendations herein apply to both types of tape collections – those accessed daily and those archived for preservation.
In this report, the audio or video program recorded on the tape is referred to as information. For example, the information recorded on an audio tape could be a sound studio recording, a concert performance, radio news broadcasts, a college lecture, or songbird calls. The information recorded on a videotape could be a TV program, a movie, a child’s recital, a videotaped interview, an artist’s original work, or a surveillance camera record. To help understand some of the terminology associated with the magnetic recording field, a Glossary is provided. Words included in the Glossary appear in italics the first time they are referenced.