Kodak D-31 User Manual

Micrographic Quality

D-31

Storage and
Preservation
of Microfilms

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Electronic Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Record Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Storage Hazards and Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Fire Protectio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Storage Vaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Cabinets and Safes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Effects of High Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Water Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Effects of High and Low Relative Humidities . . . . . . . . . . . . . . . . . . 5

High Humidit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Low Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Molecular Sieves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Humidity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Moisture-Tight Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Humidification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Fungus Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Microscopic Blemishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Toning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Chemical Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Composition of Enclosure Materials . . . . . . . . . . . . . . . . . . . . . . . 10

Paper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Plastic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Adhesive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Printing Inks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Theft Protec tio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Processing for Permanence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Silver-Gel a tin F ilms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Fixing Baths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Squeegees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Washing Aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Residual Hypo Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Residual Silver Compound Test . . . . . . . . . . . . . . . . . . . . . . . . 12

Protective Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

D-31 June 2002 i

Processing of Other Film Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Thermally Processed Silver (TPS) . . . . . . . . . . . . . . . . . . . . . . . . 13

Diazo Films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Vesicular Films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Special Storage and Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Underground Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Effects of Nuclear Ex p lo s io n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Time-Capsule S torage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Handling and F iling Film Records . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Interfiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 1: Applicable Standards for Microfilm . . . . . . . . . . . . . . . . . 15

Table 2: Storage Life of Microfilms . . . . . . . . . . . . . . . . . . . . . . . . 16

Table 3: Storage Temperature and Relative Humidity . . . . . . . . . . 17

Summary of Requirements for Storage and

Preservation of Records on Kodak Microfilm . . . . . . . . . . . . . . . . . 17

Storage Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

References and Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

ii D-31 June 2002

Introduction

Definitions

Photographic film remains an important
documentary material. The increasing quantity
and value of microfilm records used in financial
institutions, libraries, government offi ces, and
industrial firms have focused attention on the
care of such records to make certain that they
last as long as possible.

The distinction between phot ographic film recor ds
intended for storage and those intended for use
has not always been clear. Use or work copies
are the predominant photographic records found
in libraries or record centers and are subject
to much handling due to their value as quick
references. However, because of this handling,
they are subject to dirt, abrasion, fingerprints,
contamination with foreign materials, and
exposure to excessive light, temperatures, and
harmful atmospheric pollutants. As a result, these
copies in daily use cannot be considered suitable
for long-term preservation. For lo ng-t erm stor age,
it is imperative to prepare duplicate copies that
meet certain criteria, such as proper filming,
duplicating, processing, minimum handling,
controlled environment, and storage.

In general, the care needed for storing
photographic records is similar to that for
storing written paper records, although there
are some requirements peculiar to the storage
of photographic film.

The permanence of photographic records
depends on the chemical stability of the film,
how the film is processed, and the conditions
under which the processed film records are
stored. The stability of the film layers is
determined in manufacture and processing, while
storage is controlled by the user. This pamphlet
discusses the composition and properties of
black-and-white silver-gelatin, thermally
processed silver (TPS), diazo, and vesicular films
as they relate to film permanence. It also
describes the essential requirements of good
processing and storage practices.

NOTE:Refer to the latest revision of each ANSI or

ISO Standard specified.

To help understand storage requirements,
the composition and structure of microfilm are
described and definitions of commonly used

1

terms are given.

Structure of a typical black-and-white negative film.

Acetate film—(acetate base) safety film with a
base composed principally of cellulose acetate
or triacetate.

Antihalation undercoat—separate layer of
light-absorbing dye located between the film
emulsion and the base to suppress li ght reflection.
During processing of this film, the dye layer
becomes transparent.

Base or support—a flexible plastic material tha t
is coated with a thin, light-sensitive, image­forming layer. The thickness of the base varies
with different film types.

Dimensional stability—ability of photographic
materials to maintain their origina l size and shape
during and after processing and also under
various conditions of temperature and humidit y.

Emulsion—the image-forming layer. For
unprocessed black-and-white silver-gelatin films,
it is composed primarily of minute silver halide
crystals suspended in gelatin. Exposure to
light in a camera or printer causes no visible
effect, but there is an invisible change which
produces a “latent image.” To obtain a visible,
usable image, the exposed material must be
chemically processed.

For diazo and vesicular films, the sens itized layers
are composed of light-sensitive diazonium salts.
To obtain a visible, usable image with these films,
the exposed material is heat-processed. Diazo
films are typically heat-processed in the presence
of ammonia.

For TPS films, the image-forming la yer is ty pic all y
silver halide and silver salts suspended in a
polymeric binding.

D-31 June 2002 1

Emulsion layer(s)—image or image-forming
layer(s) of photographic films, papers, and plates.

Film base—the plastic support for the emuls ion
and backing layers.

Halation—halo or ghost around the desired
image on a photographic emulsion. (This is
caused by the reflection of rays of light fr om th e
base to the emulsion or by internal scattering of
light within the film.)

Nitrate film—a photographic film with a base
consisting of cellulose nitrate. Nitrate-base films
decompose with age and are not suitable for
permanent records. The manufacture of nitrate
film by Eastman Kodak Company in the United
States of America was discontinued in 1951, but
older nitrate motion-picture fil ms are often found in
storage. It is not always possible to determi ne by
visual examination if a film has a nitrate base.
However , neither KODAK nor RECORDAK
Microfilms in any width were ever made on
nitrate base.

Non-curl backing layer—a layer, usually made
of gelatin, applied to the side of the film base
opposite to that of the emulsion layer, for the
purpose of preventing curl.

NOTE:It is comparable to the emulsion layer

in thickness and is not removed in
processing. (Antihalation or other
layers removed in processing are
excluded from this definition.)

Polyester film—a photographic film having a
polyester base. This type of base manufactured
by Eastman Kodak Company is called Estar Base.
It is exceptionally tough and strong and has
excellent dimensional stability. Microfilm
emulsions on Estar Base are currently supplied
for many purposes. Kodak currently manufact ures
only microfilms on Estar Base.

Safety photographic film—photographi c film
which passes the ignition time test and burning
time test as specified in ANSI and ISO Standards.

Safety poly(ethylene terephthalate ) base—
a polyester film base for recording materials
composed mainly of a polymer of ethylene
glycol and terephthalic acid. All safety films
(both acetate and polyester) manufactured
by Eastman Kodak Company meet these
requirements. This means that they are
difficult to ignite and are slow burning.

All silver-gelatin Kodak Microfi lms on Estar Base,
when processed as recommended by Kodak,
meet the current specific ations established by the
American National Standards Institute, Inc.,
(ANSI) for films intended for use as LE 500.

Substratum (subbing or precoat)—the layer
that bonds the emulsion to the base.

Electronic Imaging

With the coming of electronic digit al imaging
systems, the need for continuing the quality
concepts already est ablished i n the micrograph ics
arena has evolved. Following are a few
key concepts.

Digitization—use of a scanner to convert
documents (on paper or microforms) to
digitally coded electronic images suitable
for electronic storage.

Digital—the use of binary code to record
information. “Information” can be text in a binary
code (e.g., ASCII), images in bitmapped form,
or sound in a sampled digital form or video.

NOTE:Information is recorded digitally for

accuracy in storage and transmission.
Some types of data manipulation are
easier in digi tal form.

Scanning—1.) In electronic imaging, scanning is
the operation which precedes digitization, where
the surface of a document is divided into pixels
and analog values are collected representing the
optical density (brightness and possibly color)
of each pixel.

2.) In electronic imaging, OCR scanning is the
conversion of marks that represent symbols into
symbols for use in a data processing system.
The paper or microfilm with the human-readable
marks is first scanned as an image, then is
analyzed to recognize the intended symbol.
The result is the set of symbolic information,
in a machine-readable code such as ASCII
(also known as handprint character recognition,
intelligent character recognition, and optical
character recognition).

3.) In micrographics, sca nning is the movement of
an image on a reader screen in a direction
perpendicular to the direction of r oll-fil m transport.

4.) Scanning is the systematic examination of
data (ISO).

2 D-31 June 2002

Scanner—a device that electro-optically conver t s
a document into a series of pixels by detecting
and measuring the intensity of light reflected or
transmitted. When initially captured, each pixel is
a level of brightness (gray or color), initially an
analog quantity, but potentially digitized.

NOTE:For many applications, total information

about each pixel is not needed and would
represent a burdensome amount of output
from the scanner. Therefore, most
scanners digitize the value of each pixel
and reduce the amount of data output to
only that which is required. For example,
output might be limited to one bit per pixel
for “black-and-white” scanning.

Scanner threshold—the brightness level above
which a pixel is considered pure white and
below which the pixel is considered pure black
(sometimes set manually [lighter/darker
setting], or set automatically based on the
average brightness of the document).

Record Classification

On the basis of required retention, photographic
records can be classified broadly as requiring
medium-term storage and long-term storage.

Archival medium—recording material tha t can
be expected to retain information forever, so
that such information can be retrieved without
significant loss when properly stored. However,
there is no such material and it is not a term to be
used in American National Standard material or
system specifications.

Life expectancy (LE)—the length of time that
information is predicted to be retrievable in a
system at 21°C and 50% RH.

LE designation—the rating for the “life
expectancy” of recording materials and
associated retrieval systems.

NOTE:The number following the LE symbol is a

prediction of the minimum life expectancy,
in years, for which information can be
retrieved without significant loss when
stored at 21°C and 50% RH.

Extended-term storage conditions—storage
conditions suitab le for the preservation of
recorded information on the majority of freshly
processed photographic films for 500 years .

Medium-term storage conditions—storage
conditions suitab le for the preservation of
recorded information for a minimum of 10 years.

Methylene blue—a chemical dye formed
during the testing of permanence of processed
microimages using the methylene-blue
method. Also called residual thiosulfate ion
and silver densitometric method.

Storage Hazards and Protection

There are a number of hazards to the sat isfactory
storage of photographic film that apply to records
intended for medium-term, long-term, or
extended-term storage. In fact, it is not always
possible to predict the desired life of recor ds at the
time they are made.

While films of medium-term, long-term, or
extended-term interest are subject to the same
hazards, the storage protection provided for
them will differ in degree because of a number
of factors. These include the cost of providing
storage facilities, desired record life, frequency
of record use, value of the records, etc. See

ANSI/PIMA IT9.11-1993

5

and ANSI IT9.2-1991.

Fire Protection

All Kodak Microfilms are slow-burning films as
defined by the American National Standards

Institute, Inc.
will burn considerably slower than paper, the
same precautions against damage by fire
should be taken for them as for paper records
of comparable value.

Depending on the importance of the records,
fire protection provided can vary from the full
protection described on the following pages for
valuable records to that provided by ordinary
office storage.

3

Even though photographic records

6

For example, LE-100 indicates that
information can be retrieved for at least
100 years of storage. Silver-gelatin films
have an LE of 500; thermally processed
silver (TPS) have an LE of 100 years.

D-31 June 2002 3

Storage Vaults

The highest degree of protection for a large
number of records is afforded by a fireproof
storage vault or record room. It should be located
and constructed in accordance with the local
building code, Fire Underwriters ’ Regulations, and
the requirements of the National Fire Protection
Association (NFPA)
room, except that an approved, controlled,
air-conditioning unit shoul d be installed. While
NFPA discourages air conditioning such an
installation, the fire hazard introduced by
openings for air-conditioning ducts can be
overcome by the use of automatic, fire-control
dampers approved by Underwriters’ Laborato ries,
Inc. These can be installed in the ducts in
accordance with recommendations of NFPA.
Sufficient insulati on should be provided in the
vault to permit satisfactory temperature control at
all seasons of the year and to prevent moisture
condensation from forming on the walls.

7

for a valuable record

8

moisture, which will expand under heat and, under
some conditions, might generate slight press ure.
However , such intense heat would be requi red on
the outside of the fire-resistant cabinet that the
cabinet would be seriously damaged from the fire
before appreciable pressure developed.

Effects of High Temperatures

In addition to complete l oss by fire , damage to film
records can also oc cur i f the y ar e exposed t o v ery
high temperatures. Excessive heat causes fil m to
buckle because of shrinkage at the edges. When
severe, this distortion affects the ease with which
the information can be taken from microfilms,
either by projection (for reading) or by printing
onto another film.

Silver-gelatin films that have been conditioned at
a relative humidity of 50% or lower will withstand
121°C (250°F) for 24 hours without significant
loss in readability or printability. At 149°C (300°F),
severe distortion can occur in a few hours.

Cabinets and Safes

For smaller quantities of records , a fi re-resistant
cabinet or safe of the type described by NFPA

will provide considerable protection. Such a safe
should protect records against a severe fire for at
least four hours.

Many fire-resistant safes and cabi nets use a type
of insulation that when heated releases moisture
and thus fills the interior of the safe with steam
during a fire. This can cause melting or stripping
of the film emulsion layer and loss of the image.
For protection, films stored in such a safe should
be placed in moisture-tight cans, as descri bed
under “Humidity Control” in this publ ication.

It is preferable to use fire-resi stant safes that are
available with an inner chamber sealed against
moisture. These are classified by Underwriters’
Laboratories, Inc., as Class 150 Record

Containers.

9

Film damage caused by steam

is not a problem with these safes.
The question is sometimes raised as to whether

microfilm stored in drawers or cabinets designed
to resist fire for several hours might, in case of a
fire, generate enough pressure to damage or
explode the cabinet. There is practically no
danger of an explosion from the storage of either
Estar Base or acetate base safety film under
these conditions. There are small amounts of
organic materials in acetate film base, as well as

7

Films that have been conditioned at a relative
humidity above 50% may show objectionable
distortion in somewhat shorter times or at lower
temperatures. Higher humidities, however , are
undesirable for other reasons, as explained later.

Thermally processed silver films will build
up background densities fairly rapidly at
temperatures of 93°C (200°F) and above.
At these temperatures, even a few hours will
produce significant loss in readability or
printability. At 149°C (300°F) or above, severe
distortion can occur in a few hours.

Diazo films, while quite stable, cont ain dye images
that can fade and/or discolor as a result of high
temperatures. Kodak Diazo Microfilms can
withstand a week at 93°C (200°F) without image
loss. At 149°C (300°F) or above, severe distor tion
can occur in a few hours.

High temperature is the greatest enemy of
vesicular film. Although Kodak Thermal Print
Films can withstand 71°C (160°F) for several
hours, high temperatures can cause a complete
loss of images if care is not taken with regard to
temperature control.

4 D-31 June 2002

Water Protection

Film records should be protected from possible
water damage, such as from leaks, fire-sprinkler
discharge, and flooding. If possible, storage
facilities should be located above basement
levels. Storage cabinets should be raised so that
the lowest shelf or drawer is at least 15.2 cm
(6 in.) off the floor and should be constructed so
that water cannot splash through ventilating
louvers onto the records. Drains provided should
have adequate capacity to keep water from a
sprinkler discharge from reachi ng a depth of

7.6 cm (3 in.).
If the record-storage area s hould become flooded,

prompt steps should be taken to reclai m any
immersed records. Allowing microfilm records
to dry, even partially, will cause the layers to
stick together. If there are no local facilities for
rewashing and drying the films immediately,
promptly place the films in a wat er-filled container
and send them to a laboratory where they can be

washed and dried properly.

10

High Humidity

Stor age in moist air, such as that frequently found
in basement rooms, and storage humid ities above
50% should be avoided; relative humidities of
40% or less are recommended for minimizing the
possibility of growth of microscopic blemishes.
At humidities above 60%, there is the additional
danger of fungus growth.

Effects of High and Low
Relative Humidities

The choice of humidity level for storage depends
on the type of photographic film and the humidity
of the work area. In order to minimize subsequent
moisture conditioning in stora ge, the humidity of
the work area should not be markedly different
from that of the storage area. Very large humidity
differences may lead to some physical distortion.
The best relative humidity for storage is the
lowest that can be achieved practically and
controlled reliably, within the limits specified

in ANSI/PIMA IT9.11-1998 and ISO 18911
their latest revisions.

5

or

These curves show the relationship between relative
humidity and the moisture content of a typical emulsion,
triacetate filmbase, Estar Base, and a complete film at
equilibrium of various relative humidities at 21°C (70°F).

Low Humidity

At low humidities, problems of brittleness or
static might arise if the films are to be handled
frequently. However, in the case of inactive
films (regardless of their intended permanence),
the increased protection that low humidity gives
against microscopic blemishes might be
desirable. The recommended humidity is
30% for silver-gelatin polyester-base film and
15% for silver-gelatin acetate-b ase film and all

other silver and non-silver films.

5

D-31 June 2002 5

Very low humidities have, in the past, caused film
to be brittle. However, film of current manufacture
has not been found to exhibit brittleness or
breaking tendencies under normal handling,
even at relative humidities as low as 15%. Old fil m
that is found to be brittle at low humidity should
be reconditioned to a higher humidity before
use. One day’s storage is usually sufficient for
conditioning a dry 16 mm roll halfway to a higher
ambient relative humidity; to bring i t to full
equilibrium requires about a week. In each case,
both sides of the roll should be exposed to the air.

Molecular Sieves

Molecular sieves are capable of absorbing most
of the potential film degradation agents such as
moisture, oxidants, solvents, and others when
kept in close proximity with the films under

confined storage.
Company recommends the use of molecular
sieves with triaceta te and polyest er-based f ilms to
reduce the physical aging of films and incre ase
the longevity of black-and-white images under
confined storage. It also prevent s ferrotyping
(mold/fungal growth on films), as it reduces the
moisture content of film.

Tests have shown that molecular sieves prevent
vinegar syndrome associated with acetate-based
films and micro-blemishes, and arrests the
oxidation of silver images due to peroxides and
ozone in the atmosphere. Using molecular sieves
slows the rate of these degradation reacti ons
under confined storage and thus extends the
keeping and longevity of older film collections.

24

Therefore, Eastman Kodak

Rate of conditioning a typical safety film from 20% to 50%
relative humidity at 21°C (70°F).

Low humidity affects the curl of silver-gelatin film,
causing a slight contraction of the emulsion layer
and resulting in a slight curl toward that side.
This is generally believed to be an advantage
because the concave emulsion surface is better
protected against abrasion. However, excessive
curl may cause difficult y in focusing images in
some microfilm readers. This can be avoided
by conditioning the film to a relative humidity of
30-50% before use. The curl of diazo, TPS, and
vesicular films is virtually unaffected by humidity.

Film handled at very low humidities may also
develop a static charge as it passes through a
reader or rewinder. This static charge will attract
dust particles that can damage the emulsion by
chemical action or physical abrasi on. Therefore,
it is important that any film handling area be kept
clean. If film is kept in a dry storage area, it may
be necessary to use the film in an office area of
higher humidity to minimize static problems.
However , as previously noted, large humidity
differences may lead to conditioning problems.

A single molecular sieve packet inserted into the
existing flip-top boxes containing microfilm will
last for five to seven years, under recommended
storage conditions. Microfilm should be inspected
periodically to off e r an opportunity to replace
the molecular sieves.

The sieves must be replaced at some interval,
depending on storage conditions. The use of
molecular sieves is cited by the American Natio nal
Standards Institute (ANSI) as another proc edure
to reduce redox blemishes caused by high
humidity conditions and oxidants in the air. For
more information or to obtain molecular sieves
(listed below), call Multisorb at 1-800-445-9890.

Molecular Sieves

Part No. Film Format Content

41 ag 43 16 mm 3.5 grams 400
41 ag 47 35 mm 7.0 grams 200
41 ag 51 105 mm 12.5 grams 125

With or without molecular sieves, it is very
important to foll ow current ind ustry r ecommended
practices for film storage, such as keeping film
under proper temperature and relative humidity
conditions. However, placing recommended
amounts of molecular sieves inside flip-top
boxes will extend the life of the films significantly.

This adds additional protection by slowing the
deterioration process.

6 D-31 June 2002

Humidity Control

Control of relative humidity is required for
preservation of permanent records.

Air Conditioning

Properly controlled air conditioning of the storage
area is definitely recommended for the optimum
long-term preservation of permanent records.
The air should be filtered to remove dust,
cleansed of gaseous contaminants, if present,
and controlled to the desired relative humidity and
temperature. Slightly positive air pressure should
be maintained within the storage room or vault .
Film should be conditioned to this environment
and then placed in containers.

Where air conditioning is not available and hi gh
humidities are likely to be present, the humid ity
of the storage area can be lowered by electrical
refrigeration-type dehumidif iers. These are readily
available and inexpensive. The storage space
should first be vapor-sealed by covering the walls
with asphalt or aluminum paint or, better yet,
paper-laminated aluminum foil or other water­vapor barriers. Painting the sto rage area is
suggested, but follow the painting precautions.
A humidistat set at the desired level of humidity
should be used to control the dehumidifier. The
humidity level should be check ed frequently with a
reliable hygrometer , such as a sling psychromete r .
For added protection against short-term moisture
effects, such as dehumidifier failure, tape the
containers as described in the following section,
“Moisture-Tight Containers.”

Dehumidifiers using desiccants should be used
with caution. They may create a danger of fine
dust particles getting on the film and causing
abrasion when the film is used. Also, when some
chemical-desiccant particles are trapped in rolls
of microfilm, they may form bleached spots.
Therefore, inert desiccates should be used, and
it is essential that the system be designed so
that particulate material cannot enter the storage
area. The use of molecular sieve packets is
recommended, as this is an efficient desiccant.
Chemically pure silica gel may also be used as
a desiccant, provided that filtration is used to
remove particle layers larger than 0.3 micron.
See ANSI/PIMA IT9.11-1998 and ISO 18911-

5

1998

or their latest revisions.

Moisture-Tight Containers

If humidity control of the storage area is not
possible, the storage of film in moisture-tight
containers is required to maintain the film’s
humidity limits. The film must be condi tioned to
the required humidity before being sealed in the
container. This requires the temporary use of an
air-conditioned cabinet or room, or an electrical
dehumidifier. Smaller quantities of film can be
conditioned for two or three weeks in a desi ccator
containing activated silica gel, and then removed
and quickly sealed.

Only properly sealed metal or glass containers
are considered moisture- and gas-proof. They
are preferred when long-term air conditioning is
not practical, when gaseous impurities may
regularly be present, or when low-temperature
storage is used.

Plastic boxes, such as Kodak Microfilm Plastic
Storage Cartons (CAT No. 108-6867—16 mm;
CAT No. 841-8741—35 mm), can be used as
protective containers in controlled areas. They
provide satisfactory protec tion against short-term
problems of moisture or gaseous impurities,
such as might occur with floods, dehumidifier
failures, sm o k e from a fire, or m o is t ure released
by insulation (upon exposure to heat) in certain
fire-resistant safes and cabinets.

With both metal and plastic containers, all
materials (including any gaskets and protective
paints or lacquers) must be non-corroding and
free of peroxides, reactive fumes, and exudations
during storage. Closed containers with friction­type or threaded twist-on l ids may require no other
seal, but should be tested for imperviousness.

If the container is in an area having the prescribed
humidity and known to be free of harmful gases,
taping is not required. If these condi tions are not
met, taping will provide satis fact o ry protection.

Plastic boxes or cans are preferable, as they
provide more insulation in case of fire.

D-31 June 2002 7

Humidification

Humidification is not necessary or desirable
unless the prevailing relative humidity is under
15%—under 30% for polyester-base films—for
long periods of time and unless the film is used
frequently and physical troubles are encountered.
Neither water trays nor saturated chemical
solutions should be used for humidification of
storage cabinets because of the more serious
danger of overhumidification. Even humidification
controlled by instrumentation is risky unless
“fail-safe” devices are installed.

Fungus Growth

Fungus spores are found in the air everywhere.
They germinate and grow under favorable
conditions. When silv er-gelatin f ilms are store d for
any length of time in an atmosphere having a
relative humidity of above 60%, fungus (often
called mold or mildew) has a tendency to grow on
the emulsion surface, the back of the film, or on
the film reel. The higher the relative humid ity, the
greater the chance of fungus attack and the more
abundant its growth. The only real protection
against fungus growth is to make certain that
conditions are unfavorable fo r its growth.

If fungus growth progresses far enough, it can
cause serious and permanent damage to film.
This takes the form of distortion of the emulsion
and eventually causes chemical breakdown so
that the gelatin becomes sticky and readily sol uble
in water. Water or water solutions should not be

used for the removal of fungus growth because
either may lead to disintegration of the image.

Clean affected film by wiping it with a soft plush
or cotton pad moistened with an approved
film-cleaning liquid, such as isopropyl alcohol.
This procedure is described in detail in a separate

Kodak Pamphlet.
Fungus can grow on most surfaces, including

diazo and vesicular films; however, these films are
more resistant to fungu s growth than sil ver-gelatin
films. If necessary, clean these film types by
wiping with a soft, plush or cotton pad, moistened
with water. Do not use solvents on diazo,

vesicular, or thermally processed silver films.

10

Microscopic Blemishes

Some processed silver-gelatin microfilms in
storage for two to twenty years have developed
microscopically small colored spots or blemishes.
The fogged leader at the outside of the roll i s most
frequently affected by the blemishes, which are
generally red or yel low i n c olor a nd s maller i n size
than the image characters (e.g., a typewri tten
letter reduced 20X) on the microfi lm. On occasion,
these spots progress further into the roll and
appear in image areas. A more detailed
description of the blemishes and of the techniques
used in inspecting microfilm is giv en in National
Bureau of Stan dards Handbook 96.

The spots are caused by local oxidation of image
silver , resulting in the formation of minute deposi ts

of yellow- or red-colored colloidal silver.
Possible oxidizing agents entering from outside
the roll of microfilm are aerial oxygen, whose
action on the film is strongly accelerated by
moisture, and atmospheric contaminants such
as peroxides, ozone, sulfur dioxide, hydrogen
sulfide, and nitrogen oxides, which all occur in
industrial atmospheres.

Assuming that your microfilm was processed to
established qualit y control s tan dards, micros copic
blemishes (redox) may occur due to the oxidation
of the metallic silver image by the presence of
oxidants in the storage area: peroxides, ozone,
nitrogen oxides, oil-based paint fumes, organic
solvents, floor-cl eaning agents, cardboard
cartons, excessive temperature and humidity,
or a variety of other materials that generate
peroxides which attack silver microfilms.

The use of low concentrations of potassium
iodide in the fixing bath (0.2 g/L) has been
recommended and has been found to provide
a good degree of protection against these
blemishes.

13

Kodak Microfilm and Prostar Fix

Solutions contain this stability-enhanci ng iodide.
Once the deterioration of the microfilm occurs,

it cannot be reversed. Silver film duplication,
Kodak Brown Toner, and the use of molecular
sieves can be used to stabilize the reaction.

11

12,13

The Kodak Disaster Recovery Laboratory
offers no charge evaluation of suspect microfilm
and can be reached at 1-800-EKC-TEST
(1-800-352-8378) or 1-585-253-3907.

8 D-31 June 2002

The conditions under which microfilm is stored
have been found to play an important role in
the development of microscopic blemishes.
Stor age in cool, dry air that is free of oxidizing
gases or vapors is an effective means for
arresting their formation and growth. Stor age
in sealed, metal cans is a sound preventive
measure, if this is practical and consistent with
the humidity requirements.

Additional protection can be obtai ned 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 microfil m, processed
to established quality control standards and stor ed
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 agent s such as Kodak Brown Toner.
Other types of toners, such as selenium or gol d,
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 atmospher e. 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 st or ed
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.

Contaminants can come from illuminating gas,
coal gas, automobile exhaust, and certain
chemical plants. They are present in harmful
concentrations in most in dustrial and ur ban areas.
Other contamination can come from ozone and
ammonia produced by certain photocopying
devices. For this reaso n, a long-term storage v ault
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-f il m
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.

5,14,15,16,17

Films not of the silver-gelatin t ype (e.g., di azo 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 of f
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, tap e splices, bleached papers,
and printing inks also cause undesirable effects.

D-31 June 2002 9

Composition of Enclosure Materials

Paper

Paper should be made from rag, bleached sulfite
or bleached kraft pulp with an alpha-cellulose
content greater than 87%. It should be free from
highly lignified fibres, such as ground wood, as
determined by the phloroglucinol spot test .

For paper in direct contact with black-and-white
photographic material, the pH should be between

7.5 and 9.5. The pH should be close to 7.0 when
in direct contac t with colo r or diazo mat erial. There
should be an alkali reserve of at least 2% (m/m).
The alkali reserve should be obtained by the
incorporation of an alkaline earth carbonate.
Neutral or alkaline-sizing chemic als should be
employed and the material should be essentially
free from particle s of m e tal. Glassine envelopes

should not be used.

Adhesive

Some photographic images can be damaged
by adhesives incorporating impurities such as
sulfur, iron, copper, or other ingredients that
might react with image silver or gelatin. Pressure­sensitive adhesives and ether-li nked products
should be avoided.

Rubber-based products such as rubber cement
should not be used. Not only might they contain
harmful solvents or plast icizers, but they might be
compounded with photographically damaging
sulfur, usually as a vulcanizer, accelerator, or
stabilizer. Even some “low-desensitizing” or
“sulfur-free” rubbers contain sulfur.

Photographic-quality gelatin and many polyvinyl
acetate and cellulose ester adhes ives are
suitable for use with paper enclosures. Heat
sealing and mechanical sealing should be used
when possible.

Plastic

Suitable plastic enclosure materials are
photographic film support materials such as
uncoated polyester (polyethylene terephthalate)
polypropylene and polyethylene. Chlo rinated
or nitrated sheeting should not be used and
cellulose nitrate, in particular, should be avoided.

Metal

Metal enclosures should be noncorrosive
materials such as anodized alumi num or st ainles s
steel. The use of steel is permissible, provided
that the surface is well protected by lacquer,
enamel, tinning, plating, or some othe r corrosion­resistant finish. Lacquer, which might give off
reactive fumes, peroxides, or exudations during
storage should not be used.

Printing Inks

Printing inks are known to cause microscopic
spots in fine-grain silver microfilm; consequently,
there should be no printed matter on the inside of
the filing enclosure. The ink used for imp rinting
the outside of filing enclosures should not bleed,
spread, or transfer, and it should not be a source
of products that attack the photograph or the
enclosure itse lf.

For additional specifications, see ANSI/PIMA
IT9.11-1998
IT9.2-1991

5

(ISO 18911) and ANSI/PIMA

6

(ISO 18903).

Theft Protection

Safes provide good protection against the theft of
valuable records. Where such records are lar ge in
number , vaults of burglar-proof construction may
be required. Theft of important records involves
double peril—that of classified films falling into
unauthorized hands and the complete loss of
valuable information. Protect ion against the latter
can, of course, be provided by storing duplicate
records in another location.

10 D-31 June 2002

Processing for Permanence

Silver-Gelatin Films

Processing is one of the most important
factors affecting the potential permanence of
photographic records. The removal of residual
processing chemicals, the exclusion of dirt
contamination, and uniform drying are factors
normally controlled by proper processing.

Processed film, for long-term storage or
permanent records, must meet the requirements

of ANSI/PIMA IT9.1-1992 (R1996) or ISO 189 01.
The ability to meet most of these requirements is
controlled in film manufacture, but films must be
fixed and washed adequately, whether given
conventional or full-r eversal processing, to meet
residual thiosulfate requirements. Films
processed without fixation, such as in halide­reversal processes and certain reversal
processes with only redevelopment, may give a
“visible, usable image,” but do not come under the
scope of the long-term storage standards.

If fixing and washing are inadequate, thiosul fates
or silver salts, or both, will be retained by the film.
These can break down, especially under poor
storage conditions, to produce yellow stain in
clear areas and fading in areas containing
image silver.

Fixing Baths

In the fixing step, undeveloped silv er-halide
crystals in the emulsion are converted to soluble
silver compounds which c an be washed away wi th
water. The chemicals most commonly used for
fixing are sodium or ammonium thiosulfate
(commonly called “hypo”). The fixing bath may
also contain other chemicals to maintain a
desirable pH, provide hardening, stabilize the
solution, protect the image from microscopic
blemishes, etc.

For maximum washing efficiency, a non-hardening
fixer followed by a non-oxidizing washing aid,
such as Microfilm Clearing Bath and Replenisher
should be used. (Call Solutek at 1-617-445-5335
to order CAT No. 414-24). Hypo eliminators

containing oxidizing agents, such as peroxide,
should be avoided. Oxid izing agents may promote

image deterioration.

To make sure that there is enough time for the
fixing reaction to be completed, specific
recommendations for each type of film should
be followed. Undeveloped silver halides are
dissolved by the fixer as complex ions of silver
and thiosulfate. As the silver content of the fixer
increases with processing, the silver -thiosulfate
complex becomes increasingly dif ficult to wash
from the film. This can be avoided by frequent
replacement or proper replenishment of the fixing
bath or by in-line recirc ulating electrol ytic recovery
of silver from the fixer.

2

Recovery of silver from fixer is advisable for
reasons of economics, conservation and ecology.
There are three principal methods of silver

recovery:
and sulfide precipitation. For additional

information, refer to Kodak Publication J-212.

18

metallic replacement, elec trolytic

Washing

Adequate washing is essential to the p ermanence
of silver-gelatin microfilm. After all undeveloped
silver halide is converted, the emulsion is still
saturated with fixing bath and some dissolv ed
silver compounds. If these are not removed by
washing, they will slowly decompose and attack
the image, causing discoloration and fading.
The effect is accelerated greatly by high humidity
and temperature. The smaller the grain size of
the image, the greater this reaction is. Microfilms,
being very fine grained, are very sensitive to
this effect.

For good washing, a rapid flow of fresh water
should be used. The water should be filtered to
remove dirt particles. To improve washing,
countercurrent and spray systems are frequently
used in processing-machine constructi on.
Washing efficiency decreases rapidly wit h
decreased temperature and is very low
at temperatures below 16°C (60°F). High
wash-water temperatures produce the most
efficient washing, but emulsion reticulation can
result if the wash-water temperature is too high
and not kept close to that of the other processing
solutions. In some cases, extremely soft water
can also cause reticulation. In the case of
contained chemical kits such as the Kodak
Miniprocessor, the manufacturer's recommended
film processing capacity should not be exceeded.

23

D-31 June 2002 11

Squeegees

It is important to use an adequate squeegee
where the film leaves the water wash and enters
the drying section. Otherwise, res idual water
droplets will dry and form visible sur face defects
and, in some cases, caus e physical stick ing of t he
film laps. In wound-up rolls, these spots may
provide places where microscopic blemishes can
form. Inspect squeegees regularly (particularly
blade and roller types) to make sure that they do
not cause film scratches.

Drying

Drying should be uniform. The drying air should
be filtered so that airborne particles of dirt or
potentially harmful chemical dust s, often present
in processing laboratories, will not become
imbedded in the emulsion while it is t acky.

In machine processing, the recommendations of
both the equipment and film manufacturer for
operating conditions and processing chemicals
should be followed.

In other modes of processing, the following factors
are involved.

Washi n g Ai ds

Using a washing aid, such as Kodak Hypo
Clearing Agent (CAT No. 146-4254—5 gal.) or
Kodak Microfilm Clearing Bath and Replenisher,
greatly increases both the rate and thoroughness
of hypo removal during the washing step.

After fixing, the film is first rinsed to remove the
major portion of hypo; nex t, the film is treated in a
Kodak Microfilm Clearing Bath and Replenisher;
then it is given a final wash.

Residual Hypo Test

The accepted criterion for adequate washing is
the methylene blue method described in ANSI/
PIMA IT9.17-1998.
the silver densitometric method, which has been
suggested by the Association for Information and
Image Management (AIIM) as a simpler and less
expensive alternative. If the silver densitometric
density difference is 0.02 or less, AIIM considers
that the methylene blue requirements for
extended-term storage record films have been
met. In both methods, a clear area of the film is
tested and residual hypo tests may be run up to
two weeks after processing. A simpler, but less
sensitive, method is the use of the Kodak Hypo
Test Kit (CAT No. 196-5847). This test gives an
indication of residual hypo, but it should not be
used as a measurement for meeting the
requirements of the ANSI specification.

NOTE:For satisfactory residual hypo levels in

films, both fixing and washing must be
acceptable—inadequacies in one cannot
be compensated by the other.

19

IT9.17-1998 also describes

Residual Silver Compound Test

ANSI/PIMA IT 9.17-199819 and ISO 18917-1999
contain a test designed to indicate residual silver
salts in the film. Such salts are an import ant cause
of image layer degradation in aged-processed
photographic films.

Protective Coatings

It should be recognized that while lacquers and
other coatings have advant ages for working pri nts
receiving hard use, they are not within the scope
of the ANSI long-term storage specifications.

NOTE:The use of hypo eliminators, such as

Kodak Hypo Eliminator HE-1, is not
recommended for microfilm because
some hypo eliminators contain oxidizing
agents that can contribute to the
formation of emulsion blisters and
microscopic blemishes.

12 D-31 June 2002

Processing of Other Film Types

Special Storage and Hazards

Thermally Processed Silver (TPS)

This film should be processed in accordan ce
with the manufacturers’ recommendations for
optimum image stability. ANSI/PIMA IT9.19-1994

and ISO-18919-1999
stability of TPS films.

24

give specifications for

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-

4

1992

and ISO 18905-1999 give specific details
for methods and measurements for proper
development for image stabil ity.

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 scratch­free and free from airborne dirt and chemicals.

Vesicular Films

The only variables in processing thermal or
vesicular films are the proce ssing 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’ reco mmend ations 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,
“Specifications for S t ability of Processed Vesicular
Film,” discuss the criteria for proper development.

21

Underground Storage

Most large industrial organizations and
government agencies have developed methods
for safeguarding vit al r ecords i n the event of a war
or a natural catastrophe. Many keep their vital
records in underground reposi tories l ocated 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.
controlled sa tisfactorily, film must be dri e d (a s
described under “Air Conditioning”), then placed
in a moisture-proof container. The film must also
be protected, as in other types of storage, again st
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 heat ing
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.

5

If humidity cannot be

Effects of Nuclear Explosio ns

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 vault s, with
duplicate copies in dif ferent locations, provides
the greatest security.

D-31 June 2002 13

Time-Capsule Storage

Only silver-gelatin fil ms conformi ng to ANSI/ PIMA
IT9.1-1998

2

or ISO 18901-1999 should be used
for time capsules or sealed in cornerstones of
buildings. Film intended for thi s kind of storage
should be conditioned to a low relative humidity
(20-30% is recommended for acetate-base films)
in a conditioning room or chamber. During
conditioning, air should be cir culated against
both roll surfaces. Conditioning times should be at
least two weeks for 16 mm film and f our weeks for
35 mm film. This conforms to ANSI/PIMA IT9.11-

1998 and ISO 18911-1999.

5

During conditioning, the film should be in t he form
intended for final storage (wound on itself or a
glass rod, not on a conventional core or reel)
because the possibility of rapid moisture change
makes it inadvisable to rewind the film after
conditioning. The cap sule should b e loaded in the
conditioning chamber, if possible; if not, the film
should be transferred immediately to t he capsule
and sealed tightly.

The capsule should be a stainless steel cylinder
gasketed cover. When there is more than one roll
of film, it is a good idea to separate rolls with
stainless steel disks of the same inside diameter
as that of the capsule. Cores, reels, or wrapp ing of
any kind should not be included; only the film it self
should be put into the capsule.

Handling and Filing
Film Records

Well-planned filing systems and proper handling
of film records are important in the storage of
records. The custodian should set up safeguards
against loss or misplacement of valuable records
and also make sure that the methods of filing and
handling do not add unnecessary wear to the
records. When films must be used, duplicates
should be made and originals retained in storage.

Interfiling

Microfilm may be subject to interactions when
stored with films of different generic types
(e.g., diazo and silver-gelatin). Do not wind
different generic fil m types on the same rol l or
store them in the same container. Diazo and
silver-gelatin microfil ms should be stored
separately before and after processing.
Diazonium salt gases emitted from Diazo
microfilm (pre- and post-process) can be
detrimental to silver-gelatin microfilm.

Continual handling of film, even under favorable
conditions, causes some wear, but wear can be
accelerated greatly by certain factors which can
be controlled. Scratching occurs when film is dirty
or equipment is poorly maintained or wrongly
used. “Cinching” causes scratches and occurs
when film is made to slide layer on layer
(e.g., when the end of a loose roll of film is pul led).
Tearing and fingerprinting occur when equipment
and handling methods are not suitable.

Remove dirt from film by wiping with a lintless
fabric pad moistened with fil m cleaner or its
equivalent. Carry out cleaning operati ons in an
atmosphere of about 50% relative humidity to
minimize the possibility that the film will become
electrostatically charged and attract dust particles.

Another proven method for removing foreign
matter from film is the use of Particle Transfer
Roller (PTR) technology. These rollers are a
polyurethane material whose tackiness and
cushiness pick up dust, hair, and other unwanted
material from a continuous moving film surface.
These rollers can be mounted in-line with most
film operations. They can be cleaned easily with
warm water and mild soap. For more information
about Particle Transfer Roller technology call
FPC, Inc., (an Eastman Kodak Company)
at 1-323-468-5774 or contact your local
Kodak Representative.

Cleanliness of the work space is essent ial to
success in these operations. Static discharge
devices are available for use when handling fi lm
which has been in dry storage. Alternatively, film
can be conditioned to a higher relative humidity
before cleaning and then reconditioned to the
original low relative humidity. Other suggestions
for improving handling operations can be found in

Eastman Professional Motion Picture Films
The Book of Film Care.

22

20

and

14 D-31 June 2002

Inspection

The potential life of photographic records depends
largely on atmospheric conditions—temp erature,
humidity, cleanliness—and the manner in which
the film is used. If storage conditi ons are kept
within the limits suggested in Table 3, inspection
of an adequate number of properly selected lot
samples should be made at two-year intervals.

While extended-term records should definitely be
kept under the recommended storage conditions,
film records of medium-term value may have
more leeway in terms of storage humidity and
temperature. Where humidity is not controll ed
closely, film should be inspected more frequently
than at two-year intervals; the inter vals between
inspection should not initially exceed six months
and then, if no deterioration is noted, can be
extended but should not exceed one year.

12

Sometimes film inspection is considered too
laborious and costly and is neglected for many
years—occasionally with unfortunate results.
If it is not always possible to open every film
can or rewind every roll at the recommended
frequency, select a few rolls at random from
the film collection each month for examination.
This approach provides some protection at a
relatively small cost. If there is any indication
that film records are not keeping properly,
storage conditions should be improved and other
protective treatments given the film. Make copies
of films that show signs of deterioration because
deterioratio n , o nc e in itiated, is an irre v e rs ib l e
process that may be restrained, but not
terminated, by improving storage conditions.
Therefore, extensive and frequent inspections
should be made.

ANSI/AIIM standards and technical reports are
available related to the inspection of silver gelatin
microforms. An example can be found in
American National Standard: “Imaging Materials–
Processed Silver-Gelatin Type–Black and White

Film–Specifications for Stability.”

2

Table 1: Applicable Standards for Microfilm

*LE is for polyester-based
**LE is for acetate-based

“Safety Film Specifications” IT9.6/

“Specifications for Microfilms on
Polyester Base”

and

“... on Acetate Base”
“Methylene Blue Method ...” IT9.17/

“Specifications for Thermally
Processed Silver Microfilms”

“Specifications for Stability of
Diazo Films ...”

“Specifications for Stability of
Vesicular Films”

“Practice for Storage of
Photographic Film”

Silver-Gelatin

Long Term

LE 500*

LE 100**

ISO 18906

IT9.1/

ISO 18901

ISO 18917

IT9.11/

ISO 18911

Thermally

Processed Silver

(TPS)

Long Term

LE 100*

IT9.6/

ISO 18906

IT9.19/

ISO 18919

IT9.11/

ISO 18911

Diazo Vesicular

Medium, Long

LE 100*

IT9.6/

ISO 18906

IT9.5/

ISO 18905

IT9.11/

ISO 18911

Medium, Long

LE 100*

IT9.6/

ISO 18906

IT9.12/

ISO 18912

IT9.11/

ISO 18911

D-31 June 2002 15

Film/Type/Parameter

Table 2: Storage Life of Microfilms

Anticipated Storage Life

Medium Term

(Minimum of 10 Years)

Extended Term

(Minimum of 100 Years)

Long Term

(Indefinitely)

Silver-Gelatin Films

Residual Hypo
Residual Silver Salts

All Films—
Storage Conditions

Temperature and
Relative Humidity

Air Conditioning Not necessary

unless film records
are subjected to
frequent or sustained
high humidity (3)

Air Purification Normal Must be free from airborne gases, dirt particles,

Enclosures Not necessary with

moisture control
and/or air conditioning

NOTES:

(1), (2)

—

Not above 0.030 grams
per square meter (1)

No more than perceptible tint by spot stain test.

See Table 3

Essential—including slightly positive air pressure.

and other contaminants.
If proper humidity control is prov ided, plastic or

metal, unsealed, can be used.
If adequate humidity control is not avai lable, only

metal or glass sealed containers are acceptable.

Not above 0.014 grams
per square meter (1)

(1) Expressed as thiosulfate ion.
(2) Specific limits have not been set—the recommended washing should be satisfactory.
(3) Dehumidification may be necessary even though automatic air conditioning is not pract ical.

16 D-31 June 2002

Summary of Requirements for
Storage and Preservation of
Records on Kodak Microfilm

Storage Facilities

The type of storage vault, safe, cabinet, or area
selected must be based on the value of the film
records and their intended storage li fe. In gener al,
one roll per container is recommended.
Containers should be stored in metal cabinets.
Cabinets should be spaced in the room so there
are no stagnant air pockets or localized areas
where temperature and humidity may reach
higher levels than the general condition. If
humidity is not controlled, sealed metal or glass
containers are required.

Table 3: Storage Temperature and Relative Humidity

Extended and Long Term Medium Term

Although the same general storage principles
apply to medium-term and long-term storage
records, much greater care must be taken to
obtain maximum protection for long-term storage
records; makeshift or temporary arrangements
should not be considered.

In summary, Table 3 indicates the conditions that
are considered suitable for black-and-white silver­gelatin, thermally processed si lver, diazo, and
vesicular Kodak Microfilms.

Film Type Base

Silver-Gelatin Cellulose ester

(Acetate)

Silver-Gelatin Polyester 30–40% 21 69.8 20–60% 25 77
Thermally Processed Silver Polyester 15–30% 21 69.8 20–60% 25 77
Diazo Polyester 20–50%

Vesicular Polyester 15–50% 20 70 20–60% 25 77
Electro-Photographic Polyester 15–50% 20 70 20–60% 25 77
Photo-Plastic Polyester 15–50% 20 70 20–60% 25 77
Color Cellulose ester

(Acetate)

Color Polyester 25–30% 2 35.6 20–60% 25 77

Relative

Humidity

20–50%
20–40%
20–30%

20–50%
20–50%

20-30%

20–40%

Temperature

(Max.)

°C °F °C °F

2
5
7

-10

-3
2

-10

-3

35.6

41.0

44.6

14

26.6

35.6

14

26.6

Relative

Humidity

20–60% 25 77

20–60% 25 77

20–60%
20–60%

Temperature

(Max.)

25
25

77
77

NOTE:If the storage temperature is sufficien tl y low or if the air where the film is to be handled is quite

moist, leave the film in its closed container until it warms up to approximate room temperature.
Otherwise, condensation of moisture will occur on the cold film surfaces.

D-31 June 2002 17

References and Bibliography

1. American National Standard: “Technical Report—
Glossary of Document Technologies,” ANSI/AIIM
TR2-1998.

2. American National Standard: “Imaging Materials—
Processed Silver-Gelatin Type Black and White
Film—Specifications for Stability,” ANSI/PIMAIT9.1­1996 or ISO 18901.

3. American National Standard: “Imaging Materials—
Photographic Films - Specifications for Safety Film,”
ANSI IT9.6-1991 (R1996) or ISO 18906.

4. American National Standard: “Imaging Materials—
Ammonia-Processed Diazo Photographic Film—
Specifications for Stability,” ANSI/PIMAIT9.5-1996 or
ISO 18905.

5. American National Standard: “Imaging Media—
Processed Safety Photographic Film—Storage,”
ANSI/PIMA IT9.11-1998 or ISO 18911.

6. American National Standard: “Imaging Media—
Photographic Processed Films, Plates, and Papers—
Filing Enclosures and Storage Containers,”
ANSI IT9.2-1991.

7. American National Standard: “Protection of Records,”
ANSI/NFPA 232-1995.

8. American National Standard: “Installation of Air
Conditioning and Ventilating Systems,” ANSI/NFPA
90A-1996.

9. American National Standard: “Tests for Fire
Resistance of Record Protection Equipment,”
ANSI/UL 72-1990.

10. “Prevention and Removal of Fungus on Prints and
Films,” Eastman Kodak Company, Kodak Pamphlet
No. AE-22.

11. “Inspection of Processed Photographic Record Films
for Aging Blemishes,” C. S. McCamy , National Bureau
of Standards Handbook 96, January 24, 1964.

12. “Microscopic Spots—A Progress Report,” D. G. Wiest
and R. W. Henn, National Micro-News, 70, 249257,
June 1964.

13. “Microscopic Spots in Processed Microfilm—Their
Nature and Prevention,” D. G. Wiest and R. W. Henn,
Photographic Science and Engineering, 7 (5),
253-261 (1963).

14. “Microscopic Spots in Processed Micr ofilm: The Effect
of lodide,” R. W. Henn, D. G. Wiest, and B. D. Mack,
Photographic Science and Engineering, 9 (3),
167-173 (1965).

15. Fundamentals, ASHRAE Handbook, New York:
American Society of Heating, Refrigerating and Air-

Conditioning Engineers, 1993.

16. HVAC Systems and Equipment, ASHRAE Handbook,
New York: American Society of Heating, Refrigerating

and Air-Conditioning Engineers, 1992.

†

†

17. HVAC Applications, ASHRAE Handbook, New York:
American Society of Heating, Refrigerating and Air-

Conditioning Engineers, 1991.

†

18. Refrigeration, ASHRAE Handbook, New York:
American Society of Heating, Refrigerating and

Air-Conditioning Engineers, 1994.

†

19. “Recovering Silver from Photographic Materials,”
Eastman Kodak Company, Kodak Publication
No. J-10A.

20. American National Standard: “Photography—
Determination of Residual Thiosulfate and Other
Related Chemicals in Processed Photographic
Materials—Methods Using Iodine-Amylose,
Methylene Blue and Silver Sulfide,” ANSI/PIMA
IT9.17-1993 or ISO 18918.

21. “Eastman Professional Motion Picture Films,”
Eastman Kodak Company, Kodak Publication
No. H-1.

22. American National Standard: “Imaging Material—
Processed Vesicular Photographic Film—
Specifications for Stability,” ANSI/PIMA IT9.12-1995
or ISO 18912.

23. “The Book of Film Care,” Eastman Kodak Company,
Kodak Publication No. H-23.

24. “The Technology of Silver Recovery for Photographic
Processing Facilities,” Eastman Kodak Company,
Kodak Publication No. J-212.

25. American National Standard: “Imaging Media (Film)—
Thermally Processed Silver Microfilm—Specifications
for Stability,” ANSI/NAPM IT9.19-1994 or ISO/DIS
14806-1996.

26. “The Effects and Prevention of the Vinegar
Syndrome,” A. Tulsi Ram, David F. Koperl,
Richard C. Sehlin, Stephanie Masaryk-Morris,
James L. Vincent, and Paige Miller, Journal of
Imaging Science and Technology, Vol. 38, No. 3,
249-261, May/June 1994.

27. “Use of Kodak Brown Toner to Extend the Life of
Microfilm,” Eastman Kodak Company, Kodak
Publication No. A-1671.

†

Available from the American Society of Heating,
Refrigerating and Air-Conditioning Engineers,
1791 Tullie Circle NE, Atlanta, GA 30329-2305.

All ANSI Specifications are available from American
National Standards Institute, Inc., 11 W. 42nd St.,
New York, NY 10036 or http://www.ansi.org.

All AIIM Standards are available from Association for
Information and Image Management, 1100 Wayne
Avenue, Suite 1100, Silver Spring, MD 20910 or
http://www.aiim.org.

Kodak Publications are available by calling
1-888-247-1234.

18 D-31 June 2002

KODAK Publication No. D-31
CAT No. 811-6386 6/2002

©Eastman Kodak Company, 2002
Printed in U.S.A.

EASTMAN KODAK COMPANY
Document Imaging
Rochester, New York 14650

www.kodak.com/go/docimaging

Kodak, Eastman, Estar, and Prostar are
trademarks of Eastman Kodak Company.