Video Guidance: Determining the Condition of Materials
How Do I Know If My Materials Are In Good Condition?
Video: Condition Assessment
See tables for each media type:
Life expectancy of video media is dependent on factors including:
- Material composition and reaction
- Storage conditions over time
- Handling over time
It is difficult to accurately predict a media’s usable life span. This is further complicated by the fact that media can change considerably between manufactured batches. But history has at least given some indication of what to expect.
- Magnetic tapes stored under archival conditions (U.S. National Archives and Records Administration example) generally have a life span of about 10 to 50 years before exhibiting difficult to handle decay. Somewhere in the middle is most common. Those stored under lesser conditions and not handled carefully will probably have a significantly shorter life span.
- Optical media come in two general categories, recordable and pressed. Pressed are generally fairly durable and can last possibly for generations if kept under favorable conditions and handled well. Recordable optical media have widely varying life expectancies. It is not entirely uncommon for some discs to become unreadable in less than 1 year. Relying on recordable discs to last for generations is probably not viable. Note however that there are manufacturers creating discs intended for archiving using more inert recording and/or reflective layers. One such new technique is M-Disc which uses a "glassy carbon" type recording layer as opposed to organic dyes.
See the Image Permanence Institute calculators to view how varying temperature, relative humidity, and dew points relate and affect life expectancy.
- Safeguarding Our Documentary Heritage: Magnetic Carriers From UNESCO
- Care, Handling, and Storage of Audio Visual Materials From the Library of Congress
- The Preservation of Magnetic Tape Collections: A Perspective From the Image Permanence Institute
- Restoration Tips & Notes, Media Formats & Resources By Richard L. Hess
- Conditions that Affect CDs and DVDs From the Council on Library and Information Resources (CLIR)
- Protect Your DVDs and CDs From the North Carolina Department of Cultural Resources