ISO 3897:1997
(Main)Photography — Processed photographic plates — Storage practices
Photography — Processed photographic plates — Storage practices
Photographie — Plaques photographiques développées — Directives pour l'archivage
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 3897
Fourth edition
1997-12-01
Photography — Processed photographic
plates — Storage practices
Photographie — Plaques photographiques développées — Directives pour
l'archivage
A
Reference number
ISO 3897:1997(E)
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ISO 3897:1997(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national standards bodies (ISO member bodies). The work of
preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be represented
on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 3897 was prepared by Technical Committee
ISO/TC 42, Photography.
This fourth edition cancels and replaces the third edition (ISO 3897:1992),
of which it constitutes a technical revision.
Annexes A to H and J of this International Standard are for information only.
© ISO 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
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Internet central@iso.ch
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Printed in Switzerland
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ISO ISO 3897:1997(E)
Introduction
Photographic plates on glass or metal supports have been in existence
almost since the beginning of photography. They have become
increasingly important as documentary and pictorial reference material in
archives, libraries, government, commerce and academia.
The stability and useful life of processed photographic plates depends on
their physical and chemical properties, as well as on the conditions under
which they are stored and used. This International Standard provides
recommendations on proper storage conditions and practices. Although it
is difficult to distinguish between the various types of plates covered by the
definitions (see 3.7 to 3.7.8) with respect to storage life, the recommen-
dations may be applied to all processed photographic plates.
The important storage elements affecting the preservation of processed
photographic plates are as follows:
— relative humidity and temperature of the storage environment;
— hazards of fire, water, and light exposure;
— fungal growth;
— contact with certain chemicals in solid, liquid, or gaseous form;
— physical damage.
The extent to which relative humidity and temperature, or variations of
both, can be permitted to reach beyond recommended limits without
producing adverse effects will depend upon the duration of exposure, on
biological conditions conducive to fungal growth, and on the accessibility of
the atmosphere to the surfaces.
The term “archival” is no longer specified to express longevity or stability in
International Standards on image materials since it has been interpreted to
have many meanings, ranging from preserving information “forever”, which
is unattainable, to temporary storage of actively used materials.
This International Standard defines two levels of recommended storage
conditions: medium-term and extended-term. Medium-term storage
conditions can be used to preserve plates for a minimum of 10 years.
Extended-term storage conditions will prolong the life of all plates, even
those not optimized for permanence.
The space requirements and costs for establishing and operating the two
levels of storage conditions (medium-term and extended-term) differ
significantly. Furthermore, the specified limits of temperature and relative
humidity for both sets of storage conditions may not be realizable due to
budgetary constraints, energy considerations, climatic conditions, building
construction, etc. However, it must be recognized that temperatures and
relative humidities which are higher than the specified conditions will
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ISO 3897:1997(E) ISO
reduce the effectiveness of the storage environment. If such deviation is
unavoidable, the environmental conditions closest to the specified limits
should be provided. In any event, the best preservation of plates will be
attained with extended-term conditions.
The recommendations of this International Standard for processed
photographic plates encompass the following:
— storage enclosures, housing and rooms;
— atmospheric and environmental conditions;
— fire protection;
— handling and inspection procedures.
This International Standard does not pertain to means or methods for
protecting photographic plates against natural or man-made catastrophes,
with the exception of fire and its associated hazards; these are sufficiently
common to warrant inclusion of protective measures.
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INTERNATIONAL STANDARD ISO ISO 3897:1997(E)
Photography — Processed photographic plates — Storage
practices
1 Scope
1.1 This International Standard specifies dark storage conditions for, storage facilities for and procedures for
handling and inspecting processed photographic plates having integral photographic layers and intended for record
purposes.
1.2 This International Standard applies to black-and-white, silver-image, gelatin, processed photographic plates as
defined in 3.7.7.
No specific distinction is made, other than the degree of care, between photographic plates for medium-term or
extended-term storage. Recommendations for plate storage relate to materials, methods, conditions, and forms of
protection applicable specifically to plates defined in the first paragraph of this subclause. However, the storage
recommendations may also be applied to lacquered and opaque plates, to black-and-white plates altered by dyes or
toners, colour plates and other historic photographic plates defined in 3.7.2 to 3.7.8. It is not intended to predict or
assign a useful lifetime to processed photographic plates stored in accordance with the specifications of this
International Standard.
1.3 Recommendations for storage of photographic films are given in ISO 5466 and for storage of processed
photographic reflection print material in ISO 6051.
Although there is some variation in recommended storage conditions among these types of photographic materials,
recommended temperature and relative humidity ranges do overlap. If all three types of photographic materials are
found in one collection or within one storage area, the temperature and relative humidity should be chosen so that
all materials are stored within their recommended ranges.
1.4 This International Standard applies to medium-term and extended-term storage conditions as defined in 3.6
and 3.2, respectively.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 5466:1996, Photography — Processed safety photographic films — Storage practices.
ISO 6051:1997, Photography — Processed reflection prints — Storage practices.
ISO 10214:1991, Photography — Processed photographic materials — Filing enclosures for storage.
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3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1 archival medium: A recording material that can be expected to retain information forever so that such
information can be retrieved without significant loss when properly stored.
NOTE — There is, however, no such material and it is not a term to be used in International Standards or system
specifications.
3.2 extended-term storage conditions: Storage conditions suitable for the preservation of recorded information
having a permanent value.
3.3 fire-protection storage facility: Facility designed to protect records against excessive temperatures, water
and other fire-fighting agents, steam developed by insulation of safes or caused by the extinguishing of fire, and
collapsing structures.
3.4 fire-resistant vault: Vault as defined in appropriate national standards and regulations ([1,2] in annex J).
3.5 insulated record containers (Class 150): Insulated record containers (Class 150) as defined in appropriate
national standards and regulations ([3,4] in annex J).
3.6 medium-term storage conditions: Storage conditions suitable for the preservation of recorded information
for a minimum of 10 years.
3.7 photographic layer: A sensitive coating that yields an image after exposure to radiant flux. Exposure is
usually followed by processing to generate the image.
3.7.1 photographic plate: A material consisting of one or more radiation-sensitive layers coated on a rigid
support, for example, of glass or metal, that yields a visible image.
3.7.2 albumen plate: A glass sheet bearing a silver halide/albumen layer which yields a visible image after
exposure and processing.
3.7.3 ambrotype plate: A glass plate collodion positive, i.e. a glass sheet bearing a thin silver halide/cellulose
nitrate layer which yields a visible image after exposure and processing. The processed negative silver image
appears as a positive when backed by a dark field.
3.7.4 collodion plate; collodion wet or dry plate: A glass sheet bearing a thin silver halide/cellulose nitrate layer
which yields a visible image after exposure and processing.
3.7.5 colour screen plate: A glass sheet bearing a colour screen consisting of dyed elements in contact with a
silver halide/gelatin layer which yields a visible image after exposure and processing.
1)
3.7.6 ferrotype plate ; tintype: An enamelled iron sheet bearing a thin silver halide/cellulose nitrate layer which
yields a visible image after exposure and processing.
3.7.7 gelatin plate; gelatin dry plate: A glass sheet bearing a silver halide/gelatin layer which yields a visible
image after exposure and processing.
3.7.8 lantern slide: A glass sheet bearing a silver halide/gelatin layer which yields a visible image after exposure
and processing. The image layer of lantern slide plates is usually protected with a cover glass, bound on all edges
with adhesive tape, as this type of plate is viewed by projection. Albumen and colour screen plates are also found
as lantern slides.
____________
1) Not to be confused with a thin metal sheet with a glossy surface upon which high-gloss photographic prints are dried.
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3.8 storage container: A box or can used to store plates.
3.9 storage enclosure: Any item in close or direct contact with recording material such as folders, envelopes,
sleeves, albums, mats, cartridges or cassettes.
3.10 storage housing: A physical structure supporting materials and their enclosures. It may consist of drawers,
racks, shelves or cabinets.
4 Photographic plate housings: storage enclosures and containers
Processed photographic plates require protection against all types of physical damage such as scratches, abrasion,
fingerprints, breakage, etc. Filing enclosures and containers provide physical protection that minimizes or prevents
such damage. Processed photographic film and prints shall not be stored within the same enclosure or container as
photographic plates. Different types of photographic plates shall not be stored together within the same enclosure or
container, but instead shall be segregated by type (see definitions in 3.7.2 to 3.7.8).
Enclosures and containers shall be designed to permit vertical storage of plates, resting on one long edge. Plates
shall not be stored in a flat or horizontal position since those on the bottom may be put under excessive pressure.
Plates made from 19th century glass are especially vulnerable to stress-related fractures when stored horizontally,
since such glass usually is not flat.
If unprotected plates are stored in contact, they shall be oriented with the emulsion side against the back side, not
emulsion against emulsion. However, plates with very fine-grain images should never be stored in contact, but in
grooved, multiple-plate containers of the type described in 4.2.
For maximum storage life, processed photographic plates shall be in a clean condition before they are placed in
storage.
4.1 Individual enclosures
All enclosures used for medium-term and extended-term storage shall meet the requirements of ISO 10214. This
includes enclosures that are in direct contact or in close proximity to the plates.
Processed photographic plates may be stored in envelopes or sleeves, file folders, folding cartons, boxes, or
albums made from paper or plastic which meet the requirements of ISO 10214. Individual plates should be placed in
suitable individual envelopes (seamed or seamless types), sleeves or folders (see annex H) to exclude dirt, to
protect the plates against mechanical damage and to facilitate identification and handling.
Suitable plastic enclosure materials are uncoated polyester (polyethylene terephthalate), polyethylene and
polypropylene. Other plastics may be satisfactory, but there has been no extended experience with such materials.
Glassine envelopes and chlorinated, nitrated or highly plasticized sheeting shall be avoided.
The adhesive used for seams and joints shall also meet the requirements of ISO 10214. The filing enclosure shall
be so constructed that the seam or joint will be at the edge of the enclosure and not in contact with the image layer.
Adhesives that are suitable for use with paper include photographic-quality gelatin, some acrylic and polyvinyl
acetate adhesives, pure starch paste and methyl cellulose.
4.2 Multiple-plate containers
Container materials should be metals, plastics or paperboard, meeting specifications in ISO 10214. The storage
container materials shall be non-corrodible. Materials made of wood, pressed-board, hardboard, particle-board and
other natural materials shall be avoided because they may contain oxidizing materials which may attack the silver
image (see annex G). Finishes on metal containers shall meet the criteria listed in clause 5 for metal storage
housings.
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There are two types of multiple-plate containers, both of which are available in commonly used plate dimensions:
1) standard document-storage containers for vertical storage of plates filed in contact with each other or a spacer
material,
2) containers having grooved, parallel tracks for holding the plates apart in fixed, vertical positions.
The first type of container must be designed to permit and maintain vertical plate storage on one long edge, as well
as allowing insertion and removal of plates without damage. This requires that the inner dimensions of the container
are only slightly larger than the plate size and that the strength and rigidity of the container are commensurate with
the weight of a full complement of plates. Rigid paperboard inserts or filler pieces meeting the requirements of
ISO 10214 can be used to ensure that plates are kept upright and to prevent them from rubbing against each other.
The second type of container shall be used when plate-to-plate contact must be avoided, as in the case of plates
having a very fine-grain image or when plates are not protected by either individual enclosures or a cover glass.
Such containers normally are lined on the bottom and sides of the interior with inserts that have parallel grooves.
The grooves have a U- or V-type cross-section to restrict contact at the extreme edges of the plates while holding
the plates vertical.
5 Storage housings
Processed photographic plates should be stored in closable storage housings suchs as vertical filing drawers or
cabinets, in storage cabinets with tightly fitting doors, or inside closed containers on open shelves. Storage
housings for photographic plates should be designed to bear a heavy weight load. Plates or plate containers should
be placed so that their weight is centred on the shelving or inside the drawer, thus minimizing the tendency of the
shelving or cabinets to topple over due to uneven weight distribution. Storage housings may be bolted to floors and
wall studs as an added precaution to secure against the danger of tipping over.
The materials used in the fabrication of storage housings should be non-combustible, non-corrosive and chemically
inert, for example, anodized aluminium, stainless steel, or steel finished with a non-plasticized synthetic resin-
powder coating. Wood, pressed-board, particle-board, plywood and other such materials shall be avoided, because
of their combustible nature and the possibility of their producing active deteriorating agents as they age.
The finish on the storage housing materials should be durable and should not contain substances that can have a
deleterious effect on the stored plates. Adverse effects may be produced by finishes containing chlorinated or highly
plasticized resins, or by solvents off-gassing from freshly applied finishes. Paints used on cabinets may give off
peroxides, solvents and other contaminants for up to three months after being applied. Metal housing materials that
have been powder-coated (a solvent-free finish process in which electrostatically applied resin particles are fused
by heat), or cabinets made from stainless steel or anodized aluminium, are recommended.
When air that is temperature- and humidity-conditioned is supplied to storage housings, adequate interior air
circulation must be provided to all shelves and drawers holding plates or their containers to ensure proper and
uniform temperature and relative humidity conditions. Storage housing located in rooms that are properly air-
conditioned in accordance with 7.1 shall be vented to permit adequate air circulation within the interior of the
housing.
Such openings shall not interfere with the requirements for fire-protection storage or water protection.
Photographic reflection prints and film may be stored within the same storage area as processed photographic
plates. Magnetic tapes and optical disks shall not be stored within the same storage area or housing as
photographic plates due to possible deleterious effects of off-gassing during storage.
5.1 Drawer cabinets
Structurally reinforced, modified office-type filing cabinets with drawers are suitable for storing individual plates
when the following handling precautions are observed:
1) care is taken to avoid uneven weight distribution and potential toppling of the cabinet when the upper drawers
are opened all the way;
2) drawers are opened and closed slowly and smoothly to avoid jostling the plates inside.
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The drawers should be flat-bottomed and the vertical height of the drawer should be slightly larger that the vertical
dimension of the plates. Drawers should be fitted with rigid vertical dividers which are the same height as the plates.
Dividers should be fixed at appropriate intervals, e.g. 2,5 cm to 5 cm and not more than 10 cm. In addition to
supporting the plates, the dividers minimize movement of plates during retrieval and filing and relieve pressure on
plates located at the end of rows. Plates should be grouped by size and shall be filed vertically in the drawers, in
one or more parallel rows depending on the plate size. Rows should be divided by suitable partitions. If drawers are
not fitted with rigid dividers, containers can be used as a means to group plates within compartments in order to
minimize jostling, and as an aid to organization and filing.
Structurally reinforced drawer-type cabinets are also recommended for storing plate containers as described in 4.2.
Containers should be filed in a single layer, i.e. not stacked on each other. Care should be taken to ensure that
containers do not tip over when other containers are removed during use.
5.2 Shelving and cabinets
Multiple-plate containers may also be stored on open-sided shelving or racks, or in door-type cabinets equipped
with shelving or racks. The spacing between shelves should allow safe retrieval and filing of containers. Containers
should be filed in a single layer, i.e. not stacked on each other, with the plates oriented vertically. The shelves
should be divided by partitions, arranged to accommodate several containers, to keep the containers upright during
retrieval and refiling. Care should be taken to ensure that containers do not tip over when other containers are
removed during use.
Door-type cabinets with shelving may be used for storing individual plates. Shelves should be fitted with rigid
vertical dividers which are the same height as the plates. Dividers should be fixed at appropriate intervals, e.g.
2,5 cm to 5 cm and not more than 10 cm. In addition to supporting the plates, the dividers minimize movement of
plates during retrieval and filing and relieve pressure on plates located at the end of rows. Plates should be grouped
by size and filed vertically.
6 Storage rooms
6.1 Medium-term storage rooms
Rooms and areas used for plate storage should be located in the same area as rooms containing provisions for
inspection and viewing of the photographic plates. Good housekeeping is essential. Walls and enclosed air-
conditioned spaces shall be designed to prevent condensation of moisture on interior surfaces and within walls,
especially during periods of low exterior temperatures when the walls may be cooled below the dew-point of the air.
Provisions shall be made against damage of photographic plates by water from floods, leaks, sprinklers and from
the steam released from masonry walls during a fire. A special storage room separated from the work areas for
plate records of medium-term interest generally will not be required, provided that the conditions recommended in
7.1 are maintained.
6.2 Extended-term storage rooms
For extended-term storage, the requirements specified in 6.1 shall be met. The value of processed photographic
plates kept for long-term purposes makes it advisable to provide a storage room or vault separate from medium-
term storage facilities, temporary storage facilities, offices or work areas.
7 Environmental conditions
The recommeded relative humidity and temperature conditions given in table 1 shall be maintained either within
individual storage housings or within storage rooms containing such housings.
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7.1 Temperature and humidity specifications for storage (see annexes B, C and D)
Table 1 — Maximum temperatures and average relative humidity ranges for storage
1)
Process Medium-term storage Extended-term storage
Maximum Relative Maximum Relative
2) 2) 3) 3)
temperature humidity range temperature humidity range
°C % °C %
3) 3)
B + W silver 25 20-50 18 30-40
1) Formerly known as “archival storage”; see introduction. For storage of historic still-photographic
records, see annex D.
2) For medium-term storage, the cycling of temperature and relative humidity shall be no greater than
– 5 °C or – 10 % respectively over a 24 hour period. The moisture content in plates shall not be greater
than the moisture equilibrium with these relative humidities.
3) For extended-term storage, a set temperature and relative humidity level should be chosen. The
cycling of temperature and relative humidity shall be no greater than – 2 °C or – 5 % respectively over
a 24 hour period. The moisture content in plates shall not be greater than the moisture equilibrium with
these relative humidities.
The rates of degradation and the potential for physical problems due to storage at low temperature and/or low
relative humidity with photographic plate materials are currently not well-known. Glass decomposition rates are very
moisture dependent at relative humidities above 40 %. However, prolonged exposure to very low relative humidity
may promote contraction or distortion of the photographic layer and potential lifting or frilling (delamination at the
edge) from the plates. Gelatin dry-plate emulsion layers having low moisture content tend to develop electrostatic
charges, causing attraction of dust which can lead to abrasion.
7.1.1 Medium-term storage environment
The maximum temperature for medium-term storage shall not exceed 25 °C, and a temperature below 20 °C is
preferable (see table 1). Some temperature fluctuation is allowable as long as the relative humidity stays within the
specified limits. Cycling of temperature shall not be greater than 5 °C over a 24 hour period.
–
The relative humidity of a medium-term storage environment shall not exceed 50 %. Cycling of relative humidity
shall be no greater than – 10 % over a 24 hour period. Storing plates at the lowest relative humidity in this range, i.e.
20 % to 30 %, may exacerbate existing physical damage such as flaking or delamination by causing the emulsion
layer to contract as moisture is extracted from the emulsion (see annexes B and D).
7.1.2 Extended-term storage environment
The maximum temperature for extended-term storage shall not exceed 18 °C (see table 1). Some temperature
fluctuation is allowable as long as the relative humidity stays within the specified limits. The variation of temperature
shall not be greater than – 2 °C over a 24 hour period.
The relative humidity of an extended-term storage environment shall be a set point within the recommended relative
humidity range of 30 % to 40 %. The variation of relative humidity shall be no greater than – 5 % over a 24 hour
period (see annexes B and D).
When processed photographic plates are handled infrequently, stability may be increased by conditioning and
storing the plates in equilibrium with air at the lower end of the recommended relative humidity range. This may be
accomplished by conditioning plates in a suitable conditioning cabinet before placing them in sealed containers or
storage housings. If plates are accessed and used at a relative humidity above 40 %, they should be reconditioned
to the storage relative humidity before they are returned to sealed containers or storage housings.
The useful life of the support and image layers of photographic plates, as well as that of all other types of
photographs, can be enhanced by storage at low temperature.
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There are two types of cold-storage “systems”: one in which the room or vault is cooled without relative humidity
control, and one in which the temperature and relative humidity are regulated and controlled to set conditions. The
first is a less expensive installation than the second, but requires that photographic materials be sealed in vapour-
and moisture-proof foil bags prior to being placed in the low-temperature storage conditions. However, glass plates
cannot be sealed easily in foil bags without puncturing the bag or physically endangering the plate during the
procedure. Furthermore, the foil bags prevent the plates from resting properly on their edges in a vertical position
during storage. Therefore, low-temperature storage areas for use with photographic plates should have regulated
and controlled relative humidity and temperature so that the use of foil bags is not necessary.
When containers are moved from low-temperature storage into work areas, they must be allowed to equilibrate with
the higher room temperature before opening, in order to prevent moisture condensation on the surfaces of the
enclosed photographs. This requires longer warm-up times with photographic plates than with films or papers,
because the heat capacity of glass is larger than that of other photographic supports.
The benefit of low-temperature storage is reduced dramatically when plates are taken out frequently and/or for
extended periods of time into higher temperature environments.
Therefore, if a plate is accessed (or anticipated to be accessed) from cold storage more than ten times a year or for
extended periods of time, copy prints or negatives of the plates should be made.
7.2 Environmental conditioning requirements
Properly controlled air-conditioning may be necessary for maintaining relative humidity and temperature within the
limits specified, particularly for extended-term storage where the requirements are more stringent than those for
medium-term storage. Slightly positive air pressure should be maintained within the storage room or vault. Air-
conditioning installations and automatic fire-control dampers in ducts carrying air to or from the storage vault shall
be constructed and maintained on the basis of recommendations contained in appropriate national standards and
regulations ([5, 6] in annex J). They shall also follow recommendations for fire-resistant file rooms contained in
appropriate national standards and regulations ([1, 2] in annex J). Mason
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