The ideal conditions are in a controlled environment. Low temperatures and low humidity improve the chemical stability of motion picture film. Under normal conditions, i.e., room temperature (about 70F) and moderate humidity (50% RH), color dyes fade, and triacetate base film decays at an unacceptable rate for long-term preservation of the materials. Cold and dry are the best conditions for the storage of film. A home freezer is the best option for long-term storage where access to the film is not required on a frequent basis. Long-term is defined in this case as longer than several months. Freezers and refrigerators control the temperature, but don't adequately control the amount of water in the air. Therefore, moisture-proof packaging is required to control the humidity in the microenvironment.

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Fresh film stored at normal household conditions (70°F and 50% RH) will have an average lifespan of 40 to 50 years before significant signs of decay occur (e.g., vinegar syndrome and color dyes density loss). Reducing the temperature by 15 degrees Fahrenheit increases that number to 100-125 years.
The recommended conditions for extended-term film storage are between 40-50 F and 20%-40% RH (relative humidity). [Preservation Calculator] Excessively dry air (below 20% RH) can lead to film becoming brittle, while damp conditions will compromise the benefits of cold temperature and invite mold growth. Good air circulation will help prevent mold growth, but mold is possible any time the RH remains above 70% for more than a few days.

Rapid changes in either relative humidity or temperature should be avoided. Many people assume that freezing is dangerous for film, but tests have shown that film is not damaged by a freeze/thaw cycle in controlled settings. There is a great danger, however, in condensation accumulating on the film so film should be frozen in steps to avoid this.

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Make sure that the film and packing materials are room temperature before beginning. It does not take long for film materials to equilibrate thermally. However, if the film was previously stored in a humid environment it may take two to three weeks to equilibrate to a drier climate.

This may be done by keeping the film in a can with the lid off in a room where the RH does not exceed 50-60% at room temperature. These conditions are necessary for the room in which you will prepare your film for freezing. Do not prepare film for freezer storage on a hot and humid day, or moisture will be trapped with the film in the bag and can.

If you have the space and the funds, you should consider buying a freezer just for your film. Depending on the size of your collection several options could be considered—e.g., a household freezer or industrial freezer.

1. Seal the cans or boxes with archival tape to make them as airtight as possible.

2. Use heavy-duty zip-lock freezer bags (3 mil or thicker).

3. Enclose one or several cans in the freezer bag and seal the bag with tape. Minimize the amount of air inside the bags. Label the bags clearly so they can be read without opening.

4. Double-bag the sealed bag containing the film and seal the outer bag with tape as above. Optional: enclose a moisture indicator in between the inner and outer bag.

5. Place in the freezer in an area where it is least likely to become punctured. Inserting cardboard supports between the packages will improve the stability of the stacks.

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When going from cold storage [38 F/ 30% RH] to normal room conditions [68 F/ 50% RH], film should first be brought into an intermediate staging area in order to avoid condensation. The climate of the staging area should ideally be midway between both the temperature and the relative humidity levels of the cold storage and the working environment so that the film never reaches its dew point. Put simply, film should go from a freezer to a refrigerator and then to the workroom.

The length of staging time needed depends on the mass of the film; a single small roll will reach its equilibrium point faster than a large reel or a stack of small reels. Six 400 ft. rolls of 16mm film will reach a usable point in 25 minutes and will be fully acclimatized in about three hours. When moisture-proof bags are used, the minimum usable point will be slightly less because the condensation will occur on the outside of the bag, not on the film. Nevertheless, it is always a good idea to leave films out for at least an hour before using them.

When it is necessary to remove the film from cold storage for use, it should be allowed to come to room temperature before any attempt is made to open the outer bag.

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If cold storage is not an option, where then should film be stored? Look around your house for possible storage locations and consider the following.

  • Do not store films in an attic. In the summer this is too hot, and the temperatures vary too much throughout the seasons.
  • Don't store film near heaters, plumbing pipes, radiators, sprinklers, windows, electrical sources, or sinks.
  • Do not store film in direct sunlight.
  • Avoid high humidity--do not store in a basement. Most basements are quite humid and perfect for mold. Also, there can be danger of flooding.
  • Avoid exterior, south-facing walls or locations that receive direct sunlight.
  • For films with magnetic soundtracks, keep away from magnets such as those found in stereo speakers as well as heavy-duty electrical cables.
  • Avoid any locations near chemicals, paint, or exhaust. Chemical fumes, including those found in everyday air pollution, when combined with a high relative humidity can cause film to deteriorate and images to fade.

Many independent filmmakers leave their original materials in storage in film laboratories. Before doing this, question the lab about their storage facilities and keep tabs on the lab, as there are countless stories about films being lost after a lab has moved, been sold, or gone out of business.

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