Microfilm Storage and Preservation Guide (EPM D-31)

The Micrographic Quality D-31 guide from Eastman Park Micrographics (July 2015 edition) reviews the composition and permanence characteristics of black-and-white silver-gelatin, thermally processed silver (TPS), diazo and vesicular films, and describes the main requirements for correct processing and proper storage conditions for microfilm records.

Highlights

• The permanence of film records depends on the chemical stability of the film, how it is processed and the storage conditions
• Day-to-day working copies are exposed to dust, scratches, fingerprints, light and pollutants and are not suitable for long-term storage
• For long-term storage, duplicate copies should be made with proper filming and processing, minimal handling and a controlled environment
• All IMAGELINK silver and non-silver microfilms are made on polyester base and have never been made on nitrate base
• IMAGELINK silver-gelatin microfilms meet ANSI specifications for LE 500 when processed according to EPM recommendations

Content overview

Photographic film remains an important documentary material, and the growing volume and value of microfilm records in financial institutions, libraries, government offices and industry make proper storage essential. The stability of film layers is determined during manufacture and processing, but storage conditions are in the user's hands.

The guide begins by defining basic terms: film base (acetate, polyester, nitrate), emulsion and latent image, antihalation layer, non-curl layer, dimensional stability and safety film. Polyester base is very durable and has excellent dimensional stability. Electronic imaging concepts such as digitization are also defined.

The main topics of the guide are:

• Record classification and storage hazards: fire, safes and secure vaults, high temperature, water, high and low humidity
• Humidity control: molecular sieves, air conditioning, moisture-proof containers and humidification
• Fungus growth, microscopic blemishes, toning and chemical contamination
• Composition of enclosure materials: paper, plastic, metal, adhesives and printing inks
• Processing for permanence: fixing bath, washing, drying, residual hypo and residual silver compound tests, protective coatings
• Processing of TPS, diazo and vesicular films
• Special storage: underground storage and time capsules
• Handling, filing and inspection of film records
• Tables of related standards, microfilm life expectancies and recommended temperature and relative humidity