Microfilm

Microforms are excellent media for long-term preservation and have long been widely used at libraries and archives for media conversion and data acquisition. The long-term storage of microforms requires a properly managed storage environment, regular surveys of the condition of the microforms, and other measures as determined per survey results. There are several types of microfilm that are commonly in use, and those with a cellulose acetate film base are known to deteriorate if stored in an inappropriate environment due to hydrolytic generation of acetic acid (vinegar syndrome). This issue affects mainly black-and-white films made between the 1950s and the early 1990s. In Japan, the black-and-white film in use was switched in the early 1990s to one with a chemically stable polyester base that is suitable for long-term storage.

Since the 1990s, the National Diet Library has proactively implemented measures to prevent the deterioration of microforms. Between 2004 to 2008, emergency measures to prevent deterioration of microforms with a triacetyl cellulose (TAC) base were outsourced to a specialist. These measures included replacing the original acid-based paper packaging with a neutral paper packaging as well as rewinding film rolls to dissipate acetic acid and inspect the film for deterioration. Problematic microforms were then cleaned or recreated.

• Brochure "Basics of Preserving Microforms" by the Preservation Division, National Diet Library (PDF: 678KB)
• Training Program for Handling and Preservation of Microfilms and Photographs in Libraries and Archives Provided by the National Diet Library (INTERNATIONAL PRESERVATION NEWS No.56 May 2012 pp.32-35) (PDF: 96KB)
• Microfilming Project (WARP)

More than 10 years have passed since implementation of these emergency measures, but long-term use can only be guaranteed by continuously guarding against deterioration and damage to the entire collection of microforms, to which end the National Diet Library Long-Term Preservation Policy for Microform Collections was established.

• National Diet Library Long-Term Preservation Policy for Microform Collections (PDF: 44KB)

• FilmCare.org (Image Permanence Institute: IPI)
• IPI Storage Guide for Acetate Film (Image Permanence Institute: IPI)
• Managing Microforms in the Digital Age (Association for Library Collections & Technical Services, American Library Association