D-31 June 2002
9
The conditions under which microfilm is stored
have been found to play an important role in
the development of microscopic blemishes.
Storage in cool, dry air that is free of oxidizing
gases or vapors is an effective means for
arresting their formation and growth. Storage
in sealed, metal cans is a sound preventive
measure, if this is practical and consistent with
the humidity requirements.
Additional protection can be obtained by adding
molecular sieves to the storage containers
or toning the film with toners such as Kodak
Brown Toner (CAT No. 146-4452—8 oz.;
CAT No. 140-0928—1 gal.). For information
about the use of brown toner as a treatment
to extend the life of microfilm, order Kodak
Publication A-1671.
26
Toning
The life expectancy of your microfilm, processed
to established quality control standards and stored
under ideal environmental conditions, can be
many years. However, we do not have control of
environmental surroundings at all times.
Therefore, you should consider taking the extra
precaution of toning your films against oxidative
attack. Toning can be accomplished by use of
sulfide toning agents such as Kodak Brown Toner.
Other types of toners, such as selenium or gold,
are also accepted but not commonly used.
ANSI/PIMA IT 9.1-1998 (ISO 18901) now
recognizes that films toned with toners like
this can still be considered to meet the standards
for records of permanent or long-term value.
Brown toning is a service offered by the
Kodak Disaster Recovery Laboratory.
The lab can be reached at 1-800-EKC-TEST
(1-800-352-8378) or 1-585-253-3907.
Chemical Contamination
Air contaminants may add an oxidizing or
reducing effect to the atmosphere. This in turn
may cause deterioration of the film base and a
gradual fading of the photographic image, as
well as the formation of the microscopic blemishes
mentioned above. Typical contaminants are
paint fumes, peroxides, nitrogen oxides,
hydrogen sulfide, sulfur dioxide, and similar
gases. If an area is to be painted, any films stored
there should be removed beforehand and should
not be returned to the area for three months.
The removal of contaminating gases from the
air requires special consideration.
5,14,15,16,17
Contaminants can come from illuminating gas,
coal gas, automobile exhaust, and certain
chemical plants. They are present in harmful
concentrations in most industrial and urban areas.
Other contamination can come from ozone and
ammonia produced by certain photocopying
devices. For this reason, a long-term storage vault
should be located as far as possible from such
areas. When a contaminated atmosphere cannot
be avoided, steps should be taken either to
eliminate the fumes by air conditioning the
storage area or to protect the film from contact
with the atmosphere by sealing it in containers.
In addition to atmospheric contaminants, care
should be taken about other materials kept or
used in the storage area. It has already been
mentioned that nitrate-base films should never be
used for permanent-record films. Furthermore,
such films should never be stored with safety-film
records (either in the same room or in rooms
connected by ventilating ducts in the same
building) because the gases given off by
decomposing nitrate film will damage or destroy
images on safety-film records.
Films not of the silver-gelatin type (e.g., diazo and
vesicular) should not be wound on the same rolls,
stored in the same containers, or be in physical
contact with silver-gelatin films. In addition, some
older vesicular films have been known to give off
acidic fumes and require a separate storage
housing with a separate circulating air system.
4
Avoid using rubber bands around rolls of film,
since residual sulfur from rubber vulcanization
promotes the growth of microscopic blemishes.
Adhesive tapes, tape splices, bleached papers,
and printing inks also cause undesirable effects.
