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 facilities.

  1. Supplies Needed for Accessing Photographs Stored in Cold Storage Vaults
    1. Clear plastic bags such as Zip-locks or flush-cut bags with twist-ties (polyethylene or polypropylene plastic bags).
    2. Cotton gloves.
    3. Carts and appropriate containers.
  2. Accessing Photographs from Humidity Controlled Cold Storage Vaults (Where photographs are not routinely stored sealed in airtight envelopes or bags)
    1. Locate individual photographs or box in cold vault.
    2. 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:
      1. the Zip-lock seal does not work or
      2. the bag has tears or holes.
    3. 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.
    4. 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.
  3. 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.
  4. Using Cold Vault Acclimation Rooms (For vaults with climate controlled acclimation rooms)
    1. 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.
    2. 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:
      1. moving directly from the cold vault into the acclimation room or
      2. 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.
  5. Accessing Photographs from Refrigerators or Vaults without Humidity Control (Where photographs are routinely stored sealed in airtight envelopes or bags)
    1. 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.
    2. 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.
  6. 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.
  7. Precautions for Accessing/Refiling Records Taken to Offsite Locations
    1. 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.
    2. 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).