PHOTOGRAPHIC MATERIALS 
written with Ana B. Hofmann

Immediate ,air-drying photographs;is the preferred recovery method for all photographic materials. It results in the least water damage and mold growth as well as less dimensional distortion. However, they must be separated and dried quickly in order to prevent sticking of emulsions and mold growth.

Photographs will stick to each other and to other materials if they are allowed to dry in a stack or block. To keep photographs damp until they can be separated, place them in sealed polyethylene bags and immerse the bags in cold water. Sometimes it is not possible to separate photographs easily even if they have been kept damp. If this is the case, do not force the photographs apart. Instead, freeze them as they are and consult a conservator.

Keep in mind that mold growth can start within 48 hours or less; furthemore, photographs made by some processes will begin to deteriorate much sooner than that. If it doesn't seem likely that you will be able to finish separating and drying the photos in a short period of time, put them in polyethylene bags and freeze them, together with any mats, enclosures or other sources of information. Freezing will slow down deterioration and mold growth.

AIR-DRYING PHOTOGRAPHS

This process should take place in a dry, clean room, as dust-free as possible. Photographs should be removed from their .i.frames ;and mats or enclosures and should be placed emulsion (image) side up on blotters or clean lint-free cloth. Before unframing, make very sure the photo is not sticking to the glass. If the emulsion is stuck to the glass or to the overmat, just remove the molding and backing and allow the photo to dry on the glass. Or freeze the photo and glass. Do not try to force them apart. If pieces have separated from the photograph, save them for later reattachment by a photograph conservator.  Do not allow the emulsion to come into contact with other materials until the photograph is completely dried.

Photographic prints which have been immersed in dirty water should be rinsed in cold, clean water before drying or freezing. Place them on a rigid support , such as cardboard or a wooden board, when moving them. They should then be tilted to allow excess water to run off. To avoid fingerprints, never place fingers on wet emulsions.

Unmounted paper-based photographs can be weighed down evenly at their edges with any small clean weights available to prevent excessive curling. If large numbers of photographs do not permit this, allow the photographs to curl on drying. The photographs can be flattened after drying by a photograph conservator. Do not try to flatten tightly curled prints.

Film-based images (non-glass based negatives and slides) can be clipped to clotheslines by non-image areas. Remove slides from wet paper mounts but save the mounts so the information can be transferred to new mounts later.

Cased photographs such as daguerreotypes; and ambrotypes; should be placed face up on clean blotters to dry. If they are waterlogged, consult a conservator for advice before proceeding.

Glass negatives and lantern slides should be handled very carefully to avoid breakage. They should be placed on blotters to dry. If lantern slides are waterlogged, it may be necessary to disassemble them by carefully slitting the paper seal around the edges and separating the photograph from the protective cover glass. Dry the photograph face up on blotters and keep the cover glass with it, also face up, for later reassembly.

RECOVERY OF PHOTOGRAPHIC MATERIALS: First priority

The following non paper-based processes should be air dried first. Dates when each process was in common use are included with most entries to aid in the first steps of identification and cataloging. Do not blot or touch the emulsions in any way. Some may not survive wetting.

• daguerreotype (1839-1860)
• ambrotypes (1851-late 1860's)
• tintypes (late 1850's-1930)
• glass plate negatives (1847-ca.1975)
• lantern slides and glass stereoviews (1850's-1940's)
• deteriorated nitrate or safety film (1887-present)         
• color slides and transparencies (1935-present)
• color negatives (1942-present)

The following paper-based processes are also first priority:           

• carbon prints (1855-present)
• gum prints (1855-present)
• woodburytypes (1865-present)
• deteriorated or unhardened gelatin prints
• color photographs (1933-present)

After attending to the materials listed as first priority, proceed to salvage other photographic materials, keeping in mind that films (plastic-based materials) are generally more stable in water than paper-based photographs.

FREEZING PHOTOGRAPHS

With large collections, immediate air-drying is not always possible due to lack of space, time and personnel. If this is the case, photographs may be packed in plastic bags and frozen in stacks to await thawing and air drying, Keep groups together. If possible, a conservator should be consulted about problems unique to the collection before freezing and thawing.

The photographs must be kept wet until they are frozen and they should be frozen at a rapid rate to -5_C or colder. Research has shown that interleaving of the photographs before freezing is not necessary; however, the stacks should be kept small enough that all the photographs in the stack can be air dried upon thawing.

As the photographs thaw, they can be separated by peeling them off the stack one at a time. A .i.microspatula ;can be helpful. Although it is not strictly necessary to prevent sticking when freezing, interleaving with non-woven polyester fabric before freezing will certainly make it easier to separate and support the photographs upon thawing. Air dry as described above.

OTHER RECOVERY METHODS FOR PHOTOGRAPHS

If photographs cannot be air-dried immediately, freezing followed by air-drying, as described above, is the next best method.

Freeze-drying is a method of last resort and should not be used with some processes. Sticking of emulsions has sometimes been observed with freeze-dried photographs. Discuss the nature of your collection with a conservator when considering this course of action.

Vacuum thermal drying is not recommended for any type of photographic material as it will cause photographs to stick together in a solid block.

RECOVERY OF FILM ON REELS

Microfilm; and motion picture film; must not be allowed to start drying rolled up because the emulsions will stick. Best results will be obtained if the films are washed and dried by a film processor. Some companies that make microfilm will also reprocess it. Motion picture film must be handled by a motion picture film processor. 

MOTION PICTURE FILM

Wet motion picture film can be sent to a motion picture film processor to be rewashed and dried. Fill film can with clean, cold water and reseal, or follow the directions of the processor. Keep the film wet until it is shipped. This should be done within 72 hours. 

MICROFILM

In the case of microfilm copies, it may be cheaper to make new service copies from the print masters than to salvage wet film. However, if the master negatives get wet, they might well be irreplaceable and salvage might be the only alternative.

Wet rolls of microfilm can be sent to a microfilm processor to be rewashed and dried. Put rolls of microfilm into water-tight containers and fill with clean, cold water, or follow the directions of the processor. Send the film within 72 hours.

If the microfilm was made by Kodak, Agfa  or Fuji, it can be sent back for reprocessing at no charge to the customer except for shipping costs. Each company will give directions for packing.

COMPUTERS AND DISKS  computers and disks, recovery

The best method of preservation is the backing up of data on disks, tape or other means. The method will depend on the size of the institution and how intrinsic computer use is to its operation. In a small museum or historical society, each staff member can back up the day's work on disks and store them off-site in a waterproof container. Copies of catalogs, inventories and other data bases should likewise be off-site, the same applies to software installation disks. This suggestion usually comes with new software and it is excellent advice that should be heeded.

The truly valuable part of a computer is the information in it. Therefore, salvage should concentrate on the retrieval and copying of the hard drives and disks or CD's. This can be done by specialist firms such as those listed in Section 6. Certain of the salvage companies also offer this service. If the institution is sending books or other materials to be freeze-dried, the salvage company might also be the most convenient and economical choice for this aspect of the recovery process.

Some vendors do offer recovery of computers, radio and TV equipment, laboratory instruments, phone systems and so on. (See Section 6, p 82.) This possibility can be explored as part of disaster planning; in an emergency, it will be easier to evaluate options and compare costs if there has been some previous contact with such specialized companies.

Computers and other hardware generally must  be replaced after a water disaster. Since these items lose value extremely fast, it is important that insurance; coverage be for replacement cost, not for the value of the hardware at the time of the disaster.

A library or archives center with large data bases is probably tied in to a mainframe or local area network. There is also likely to be a Chief Information Officer or department in charge of computers. The systems or technical support officer should contact the network to find out how often the system is backed up and decide if the methods are adequate for the institution's needs.

Remember that fire and water are not the only perils to computers: power outages, lightning, viruses, phone disturbances, construction dust, etc., are all likely to cause trouble.

MAGNETIC TAPES

Purchase new copies of magnetic tapes (videotapes, audio tapes, etc) that can be replaced. Unique tapes should be removed from water and sent to be cleaned, dried and copied. They should not be frozen. Some companies specialize in this service; all the large salvage firms can subcontract this part of the recovery as necessary. Don't put tapes that have been wet into VCR's or other players to avoid possible damage to the machine.

PHONOGRAPH RECORDS

Phonograph records were made of plastic or vinyl from about 1969 on. Most LP's are about 12". These records survive wetting quite well if they are not allowed to become moldy. A commercial disk washing product can be used to remove dirt or mold. Wipe them dry with lintless cloths and make sure to retain any labels that might have become detached. When they are quite dry, place each LP in an archival sleeve, available from conservation suppliers and store upright on wide shelving or in archival boxes.

Earlier records were made of many materials including metal, glass, acetate, shellac, and paper. They are fragile and suffer damage according to the type of material. They warp, shatter and can be etched or embossed by contact with other materials. Contact a conservator or a commercial audio recovery firm for advice on handling these. Properly stored records will be more protected and will survive an emergency much better.