Kodak D-31 - Manual (Page 16)

D-31 June 2002 13
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-18919-1999
24 give 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-
1992
4 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.
5 If 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.