by
Sarah S. Wagner
1991
Document
Conservation Laboratory
NARA Preservation Programs
These
guidelines should be followed when storing and handling photographs
in cold storage vaults at all National Archives facilities.
I.
Supplies Needed for Accessing Photographs Stored in Cold Storage Vaults
A.
Clear plastic bags such as Zip-locks or flush-cut bags with twist-ties
(polyethylene or polypropylene plastic bags).
B.
Cotton gloves.
C.
Carts and appropriate containers.
II.
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
A.
Locate individual photographs or box in cold vault.
B.
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:
i.
the Zip-lock seal does not work or
ii.
the bag has tears or holes.
C.
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 photographs inside.
DO NOT REMOVE BAGS UNTIL ITEMS NO LONGER FEEL COOLER THAN THEIR SURROUNDINGS
DO NOT ATTEMPT TO SPEED UP THE WARMING OF THE ITEMS BY PLACING NEAR
HEAT
D.
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.
III.
Refiling from Office Conditions to Humidity Controlled Vaults
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.
IV.
Using Cold Vault Acclimation Rooms (For vaults with climate controlled
acclimation rooms)
A.
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.
B.
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 when:
i.
moving directly from the cold vault into the acclimation room or
ii.
the items have warmed up to acclimation room conditions and then
are moved to office conditions.
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.
V.
Accessing Photographs from Refrigerators or Vaults without Humidity
Control (Where photographs are routinely stored sealed in airtight envelopes
or bags)
A.
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.
B.
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.
VI.
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.
VII.
Precautions for Accessing/Refiling Records Taken to Offsite Locations
A.
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 deterioration.
B.
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).
Courtesy
of
US
National Archives and Records Administration (NARA).
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