Kodak D-31 manual Toning, Chemical Contamination

The conditions under which microfilm is stored have been found to play an important role in the development of microscopic blemishes. Storage in cool, dry air that is free of oxidizing gases or vapors is an effective means for arresting their formation and growth. Storage in sealed, metal cans is a sound preventive measure, if this is practical and consistent with the humidity requirements.

Additional protection can be obtained by adding molecular sieves to the storage containers

or toning the film with toners such as Kodak Brown Toner (CAT No. 146-4452—8 oz.; CAT No. 140-0928—1 gal.). For information about the use of brown toner as a treatment to extend the life of microfilm, order Kodak Publication A-1671.26

Toning

The life expectancy of your microfilm, processed to established quality control standards and stored under ideal environmental conditions, can be many years. However, we do not have control of environmental surroundings at all times.

Therefore, you should consider taking the extra precaution of toning your films against oxidative attack. Toning can be accomplished by use of sulfide toning agents such as Kodak Brown Toner. Other types of toners, such as selenium or gold, are also accepted but not commonly used. ANSI/PIMA IT 9.1-1998 (ISO 18901) now recognizes that films toned with toners like

this can still be considered to meet the standards for records of permanent or long-term value. Brown toning is a service offered by the Kodak Disaster Recovery Laboratory.

The lab can be reached at 1-800-EKC-TEST (1-800-352-8378) or 1-585-253-3907.

Chemical Contamination

Air contaminants may add an oxidizing or reducing effect to the atmosphere. This in turn may cause deterioration of the film base and a gradual fading of the photographic image, as well as the formation of the microscopic blemishes mentioned above. Typical contaminants are paint fumes, peroxides, nitrogen oxides, hydrogen sulfide, sulfur dioxide, and similar gases. If an area is to be painted, any films stored there should be removed beforehand and should not be returned to the area for three months. The removal of contaminating gases from the air requires special consideration.5,14,15,16,17

Contaminants can come from illuminating gas, coal gas, automobile exhaust, and certain chemical plants. They are present in harmful concentrations in most industrial and urban areas. Other contamination can come from ozone and ammonia produced by certain photocopying devices. For this reason, a long-term storage vault should be located as far as possible from such areas. When a contaminated atmosphere cannot be avoided, steps should be taken either to eliminate the fumes by air conditioning the storage area or to protect the film from contact with the atmosphere by sealing it in containers.

In addition to atmospheric contaminants, care should be taken about other materials kept or used in the storage area. It has already been mentioned that nitrate-base films should never be used for permanent-record films. Furthermore, such films should never be stored with safety-film records (either in the same room or in rooms connected by ventilating ducts in the same building) because the gases given off by decomposing nitrate film will damage or destroy images on safety-film records.

Films not of the silver-gelatin type (e.g., diazo and vesicular) should not be wound on the same rolls, stored in the same containers, or be in physical contact with silver-gelatin films. In addition, some older vesicular films have been known to give off acidic fumes and require a separate storage housing with a separate circulating air system.4

Avoid using rubber bands around rolls of film, since residual sulfur from rubber vulcanization promotes the growth of microscopic blemishes. Adhesive tapes, tape splices, bleached papers, and printing inks also cause undesirable effects.

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