As noted, the storage of microform is critical to ensuring its longevity. Even if the film base, capture procedures, and processing conform to standards, substandard storage can rapidly negate all the care taken. Master negatives are used only when the other generations of film are exhausted from use, and it is devastating when they are found to be unreadable because of poor storage. One of the basic lessons is to duplicate and distribute film copies to avoid the possibility of complete loss. Ideally, master negatives should be stored in a safe, fire- and flood-proof environment with a constant temperature of 18°C and relative humidity of 35 percent. The air filtration system in the storage facility should remove harmful chemical pollutants and provide adequate air circulation.

To repeat, the camera negative must be stored far from the other film generations. In the United States, research libraries store their camera negatives in very stable underground storage complexes such as the National Underground Storage/Iron Mountain facility in Boyers, Pennsylvania. (See http://www.ironmountain.com/ for services available.) Such storage opportunities are rarely available in developing countries, so some consideration should be given to inter-institutional cooperation in securing facilities. (See COLLABORATION.)

The enclosures in which film is housed should also be taken into account when trying to extend the life of preservation film (see CONSERVATION). If the storage facility is acceptable, high-quality acid-free, buffered board/paper boxes are the best and most economical way to house film reels. There is some evidence that sealed, nonferrous metal or certain plastic containers might slow down the process of deterioration in unsatisfactory storage conditions, but not for acetate film. One type of enclosure that can combat industrial pollutants is made from a MicroChamber board, which uses zeolite to absorb and neutralize most pollutants (see http://www.conservationresources.com/).