Microfilm and Microfiche are typically used for the archival storage of important information. This medium allows people to preserve and compact large amounts of information into a much smaller storage space. It is of the highest importance that Microfilm and Microfiche are stored under the right conditions. If proper conditions are not provided, symptoms of deterioration in photographic images can be detected in some environments in as little as 2 – 5 years. Perpetual Storage, Inc. ensures that conditions are kept at the correct levels for storing these as well as other types of media.
Definitions:
Microfiche usually replicates multiple individual pages in single fiche sheets. It can be made up of strips of film cut from rolls and placed in polyester jackets, or made by filming with a “step and repeat” camera, with images imposed directly onto a single sheet of film.
Microfilm is available in 16 or 35 millimeter widths with 35 millimeters the norm for preservation filming. Microform is now available as silver-gelatin, diazo, and vesicular.Microfilm is available in 16 or 35 millimeter widths with 35 millimeters the norm for preservation filming. Microform is now available as silver-gelatin, diazo, and vesicular.
Film Bases According to the Northeast Document Conservation Center:
“Through the years, microforms have appeared on various film bases, including cellulose nitrate, cellulose acetate, and polyester.
Cellulose nitrate-based microforms, like other cellulose nitrate films, are highly flammable, prone to releasing hazardous gases over time, and subject to natural decomposition. By the early 1950s, commercial production of all formats of cellulose nitrate film had permanently ceased.
Cellulose acetate film, touted as safety base film and non-flammable, will still naturally degrade over time. This degradation process is accelerated when acetate film is not properly stored. Although a great deal of acetate microfilm exists, acetate film is not acceptable as a preservation medium for microforms.
Polyester is the only film base currently recommended for preservation microfilming. Both stable and durable, black-and-white polyester film has a life expectancy of 500+ years under proper storage conditions.” The 500-year estimate is based on independent laboratory tests using artificial aging techniques and observation of film over a considerable time.
Ideal Storage Conditions for Microform Media:
- Storage areas should be environmentally controlled to the proper temperature and humidity. The international standard, ISO 18911:2010, specifies conditions for master microfilm negatives.
Medium Term Extended Term
Temperature: (Max) 77° F 25°C. 70° F. 21°C
Relative Humidity: 20% – 50% 20% – 30%
- Polyester-based silver film requires a temperature cooler than 70°F (2°C); 50-59°F is preferred. The temperature should not vary ±3° F in a 24-hour period. The relative humidity for polyester-base film should have a set-point between 25% and 45%, and should not vary more than ±5% during a 24-hour period.
- Cooler storage is critically important for older cellulose-base film (nitrate and acetate). The maximum temperature is 45°F and relative humidity should be 20-30%. The same daily fluctuations apply for cellulose-based film as for polyester film.
- The storage area should have a separate heating/ventilation/air conditioning (HVAC) system. Whenever the storage area is to be sprayed or painted, all films should be moved off-site until the air has been re-purified. The length of time required will be dependent on the environment, equipment, and chemistry of the spray or paint.
- The facility’s dehumidification air-delivery system must be equipped with a filter capable of removing dust, airborne gases, dirt particles and other pollutant particles. ISO 18911 (Was ANSI IT 9.11)
- Film housings/storage cabinets should be made of non-corroding, non-deteriorating, and non-ferrous metals or plastics.
- Button-and-string ties are appropriate for securing film on the reel as long as they meet the appropriate standards. Do not use tape, strings, rubber bands, or adhesives to secure or fasten film for storage.
- Cardboard boxes used for storage should be acid-free and lignin-free. When purchasing film or storage boxes, always ensure that the items meet national and international standards for archival storage.
Problems That Arise From Improper Storage of Microform Media:
Vinegar Syndrome— “More properly referred to as acetate film base degradation…Its causes are inherent in the chemical nature of the plastic and its progress very much depends on storage conditions.
The symptoms of vinegar syndrome are a pungent vinegar smell (hence the name), followed eventually by shrinkage, embrittlement, and buckling of the gelatin emulsion. Storage in warm and humid conditions greatly accelerates the onset of decay. Once it begins in earnest, the remaining life of the film is short because the process speeds up as it goes along. Early diagnosis and cold, moderately dry storage are the most effective defenses.” (According to The National Film Preservation Foundation)
Redox Blemishes: Some processed negative microfilms in storage for two to twenty years have developed microscopically small colored spots or blemishes. The fogged leader at the outside of the roll is most frequently affected by the blemishes, which are generally red or yellow in color and are smaller in size than the image characters (for example, a typewritten letter reduced 20X) on the microfilm. On occasion, these spots progress further into the roll and appear in image areas…The spots are believed to be caused by local oxidation of image silver, resulting in the formation of minute deposits of colored colloidal silver. Possible oxidizing agents entering from outside the roll of microfilm are aerial oxygen, whose action on the film is strongly accelerated by moisture, and atmospheric contaminants, such as peroxides, ozone, sulfur dioxide, hydrogen sulfide, and nitrogen oxides, all occurring in industrial atmospheres.
The Negative Effects of Fluctuating Temperature and Humidity Levels & Other Factors:
“If low temperatures are maintained for the storage of collections, and if readers are located outside of the storage areas, a conditioning period is required to allow gradual warming of cold films before they are read. Rapid transfer from a cold to a warm space may cause water condensation on the surface of the films.” (According to the Northeast Document Conservation Center)
If the environment is too cold and dry it can cause the film to become embrittled and render the information unreadable. It may also cause static.
If the film is exposed to too much humidity microscopic blemishes growth may occur—also fungus growth.
If film is exposed to extreme temperatures it will distort in the space of a day or even just a few hours if the temperatures are high enough.
If the film is exposed to water it must be treated immediately otherwise once the film dries the layers will stick together. If no facility is immediately available to treat your film, the film should be immediately placed in a water filled container and sent to a laboratory where they can be washed and dried properly.
Unfortunately, ideal storage conditions are rarely found in courthouses, city halls, and typical office facilities. In general, bank vaults are not recommended since they are not in the business of storing large volumes of records for other entities. Perpetual Storage, Inc. stores your Microfilm and Microfiche in ideal conditions.
Perpetual Storage stores these sensitive microfilm reels and microfiche under environmental conditions that fall under stringent ANSI Guidelines for the storage of these types of media.
The below link contains a select list of standards content from ANSI and ISO:
ISO standards are available at www.iso.ch, or may be purchased in paper from the ISO offices in Geneva. The American National Standards Institute (ANSI) also has stringent standards for the production and storage of microfilm; they may be accessed through www.ansi.org.
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