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Cold Storage Handling Guidelines for Photographs
by Sarah S. Wagner
Document Conservation Laboratory
NARA Preservation Programs
These guidelines should be followed when storing and handling
photographs in cold storage vaults at all National Archives
- Supplies Needed for Accessing Photographs Stored in Cold
- Clear plastic bags such as Zip-locks or flush-cut bags
with twist-ties (polyethylene or polypropylene plastic bags).
- Cotton gloves.
- Carts and appropriate containers.
- Accessing Photographs from Humidity Controlled Cold Storage
Vaults (Where photographs are not routinely stored sealed in
airtight envelopes or bags)
HANDLE GENTLY--COLD PHOTOGRAPHS ARE BRITTLE AND ARE EASILY
DAMAGED BY FLEXING
- Locate individual photographs or box in cold vault.
- Place the photographs or box inside the plastic bag.
Squeeze out the excess air from the plastic bag and seal the bag.
Do not use the bag if:
- the Zip-lock seal does not work or
- the bag has tears or holes.
- Place bagged photographs or box in a designated holding
area. If feasible, spread out bagged items to allow better air
circulation. Allow photographs to warm up slowly in a cool dry
area, such as an office or processing area.
Small quantities of photographs will warm up faster than large
groups or boxes. Warm up time to room temperature may take 30
minutes for one or two photographs or two to four hours for
boxes, depending on the size of the box and quantity of
DO NOT REMOVE BAGS UNTIL ITEMS NO LONGER FEEL COOLER THAN THEIR
DO NOT ATTEMPT TO SPEED UP THE WARMING OF THE ITEMS BY PLACING
- When bagged photographs or boxes no longer feel cool to
the touch and are at room temperature, wipe off any excess
moisture condensed on the bag and open bag to remove items.
- Refiling from Office Conditions to Humidity Controlled
Place photographs or box inside cold vault while pulling other
items. If reshelving a box, open box during this time to let
warmer air escape prior to reshelving. Handle other photographs
carefully during refiling to avoid flexing cold items.
- Using Cold Vault Acclimation Rooms
(For vaults with climate controlled acclimation rooms)
Items do not need to be bagged if moved only from the cold vault
to the acclimation room for inspection, etc. If the items then
are allowed to warm up to acclimation room conditions, they can
be moved to office conditions without the need for bagging.
However, items must still warm up to room temperature prior to
use because plastic film is brittle at cold temperatures.
- Use the acclimation room when entering/exiting a vault
in order to minimize the influx of warm air and the resulting
climate fluctuations in the vault.
- The acclimation room climate is set at a temperature and
relative humidity specific to the climate of the cold storage
vault so that no moisture condensation will occur on materials
- moving directly from the cold vault into the
acclimation room or
- the items have warmed up to acclimation room
conditions and then are moved to office conditions.
- Accessing Photographs from Refrigerators or Vaults without
Humidity Control (Where photographs are routinely stored sealed
in airtight envelopes or bags)
- Photographs or boxes should be sealed in heavyweight
plastic bags or in special metallic foil/plastic bags when stored
in stand alone refrigerators and freezers or in low cost vaults
without climate control. These types of cold storage systems
experience wide fluctuations in humidity either during normal
operation or when opened for access to the records. Humidity
levels can fall below the levels recommended in order to prevent
extreme brittleness or levels can rise to the point where
photographs become moist and allow mold to grow.
- Procedures described above in Section II should be
followed except that photographs or boxes must be resealed in
bags prior to refiling in the vault.
- Precautions against Catastrophic Vault Failure
In some cases, photographs are routinely bagged for cold storage
as insurance against catastrophic failure, even when there is
adequate climate control in the cold vault. Examples of
catastrophic failure include long term power outages, a loss in
climate control in which the temperature and/or relative humidity
rises rapidly, or water release. Bagging for storage is a wise
precaution if the vault is unreliable in terms of climate
control, where there are no backup power units or redundant
climate control systems, or for extremely valuable photographs
where any potential risk is considered unacceptable.
- Precautions for Accessing/Refiling Records Taken to Offsite
- Records taken offsite should be placed in an insulated
container, such as a small picnic cooler or chest, during
transit. Insulated containers are available in a wide range
of sizes from beverage size up to several cubic feet in capacity.
Insulated containers will prevent the records from being exposed
to extreme weather conditions which could accelerate
- Records which were offsite should be allowed to
acclimate to in-house office conditions before they are refiled
to cold storage. This acclimation period should be either
several days for single items or a week for boxes. This
procedure is especially important where records might have been
exposed to higher humidity levels at the offsite location (such
as a laboratory).