Microfilming is governed by a variety of standards, but it is important to keep in mind that most of these standards were developed for commercial microfilming applications, where the microfilm being produced only needs to be retained for a limited time. Thus, certain practices may be acceptable in the production of commercial microfilm that are not appropriate in the production of preservation microfilm.
Preservation microfilming of paper-based collections makes up only a small fraction of the micrographics industry, so addressing preservation filming is not a high priority for standards-making organizations. The American National Standards Institute (ANSI) issues various standards pertaining to imaging materials, including microfilm, and the Association for Information and Image Management (AIIM) also issues standards for micrographics. These standards can be useful in providing general information, but it is up to the individual institution to decide what level of quality is acceptable.
For specific guidelines for preservation microfilming geared toward libraries, archives, and other institutions that hold paper collections, the Research Libraries Group (RLG) has produced three publications that have come to be considered de facto standards. The RLG Preservation Microfilming Handbook (1992), the RLG Archives Microfilming Manual (1994), and the RLG Guidelines for Microfilming to Support Digitization (2003) should be consulted by any cultural institution planning a preservation microfilming project. Another basic resource is the Association of Research Libraries' Preservation Microfilming: A Guide for Librarians and Archivists (1996). All of these publications are referenced in Additional Resources.
These guidelines specify materials and procedures that must be used to ensure the permanence of the film that is produced:
Microfilm camera negatives (master negatives) must be produced on silver film. Duplicate negatives are also usually silver gelatin. Service copies can be made on diazo or vesicular film if desired.