Kodak D-31 manual Processing of Other Film Types, Special Storage and Hazards, Diazo Films

Processing of Other Film Types

Thermally Processed Silver (TPS)

This film should be processed in accordance with the manufacturers’ recommendations for optimum image stability. ANSI/PIMA IT9.19-1994 and ISO-18919-199924give specifications for stability of TPS films.

Diazo Films

The proper processing of diazo films can also affect keeping qualities. In the diazo process, the film should be processed to completion for maximum storage stability. ANSI/PIMA IT9.5- 19924 and ISO 18905-1999 give specific details for methods and measurements for proper development for image stability.

Also, as with conventional silver films, if processing equipment utilizes squeegees and dryer chambers, regular inspections should be made to make sure that the process is scratch- free and free from airborne dirt and chemicals.

Vesicular Films

The only variables in processing thermal or vesicular films are the processing temperature and time. Insufficient processing can increase the possibility of fading in the heat of the reader and potentially shorten keeping life. Processing within manufacturers’ recommendations should maximize keeping qualities. In addition to monitoring process temperature and time, regular checks should be made to make

sure that scratch-free film is being produced. ANSI/PIMA IT9.12-1995 and ISO 18912-1999,21“Specifications for Stability of Processed Vesicular Film,” discuss the criteria for proper development.

Special Storage and Hazards

Underground Storage

Most large industrial organizations and government agencies have developed methods for safeguarding vital records in the event of a war or a natural catastrophe. Many keep their vital records in underground repositories located many miles from large metropolitan areas. When microfilm is kept underground in caves, mines, tunnels, subbasements, or similar locations, special care should be taken to make certain that there is adequate control of the relative humidity.

Film should not be stored where the relative humidity exceeds the limits recommended for storage. See Table 1 of ANSI/PIMA IT9.11-1998 or ISO 18911-1999.5If humidity cannot be controlled satisfactorily, film must be dried (as described under “Air Conditioning”), then placed in a moisture-proof container. The film must also be protected, as in other types of storage, against airborne dirt or chemical contamination.

In underground situations, proper film-storage conditions can often be achieved by simply heating the cool, moist air that is present.

For example, conditions in a typical mine may be 10°C (50°F) and 85% relative humidity; by heating the storage area to 21°C (70°F), the relative humidity is reduced to 40%. Where it is not practical to lower the relative humidity adequately by this means, supplementary dehumidification may be required.

Effects of Nuclear Explosions

The protection of vital microfilm records against the effects of nuclear explosions is mostly a matter of providing sufficient blast and fire protection. Processed microfilm is essentially unaffected by radiation, even of the intensity encountered in the vicinity of a nuclear explosion. Best protection from blast and fire is afforded by removing security files from potential target areas. Storage in underground vaults, with duplicate copies in different locations, provides the greatest security.

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