Exploring

Preservation Microfilming

The Filming Process

For most institutions, contracting out for microfilming services is the most efficient and cost-effective choice, since setting up an in-house lab to produce microfilm that conforms to standards and guidelines for preservation filming is extremely difficult and expensive.

The basic procedures involved in preservation microfilming are as follows:

• Preparing Collections for Filming—The materials are examined page-by-page to ensure that they are in the correct order and nothing is missing. Targets are created (informational sheets with bibliographic and condition information that are photographed with the item to assist the user), and reel breaks are determined. During the review process, special instruction for the filmers are noted. The materials are shipped to the vendor.



Filming a document using a planetary camera.
• Filming—A planetary camera (where both the camera and the materials are stationary during filming) is most commonly used. Bound materials may be filmed using a book cradle. Manual exposure is usually necessary for collections with variations in paper color, texture, and/or ink.


• Film Processing—Silver gelatin film processors may be tabletop or deep tank models. They develop, fix, wash, and dry the film. Filmers should use control strips daily to check the performance of the processor.


• Polysulfide Treatment—This treatment was developed to combat the formation of redox spots or rings on silver microfilm, which are a result of poor environmental conditions and exposure to pollutants. Polysulfide treatment (which converts the silver to a form that better resists oxidation) can be used during initial processing, it can be provided for the master and duplicate negatives after all quality control inspections have been done, or it can be applied to older film, as long as it is not yet deteriorated.



Quality control check.
• Quality Control—Before duplication, the master negative is inspected for proper resolution and density; a methylene blue test (for residual thiosulfate from processing) and a polysulfide test (as needed, if polysulfiding treatment was applied during original processing) are conducted; and the master negative is inspected frame-by-frame to ensure that each document has been filmed in the correct order and each frame is legible. If necessary, mistakes are corrected using ultrasonic splicing.


• Duplication—The choice of film for duplicates will depend on cost and use patterns. Silver film is preferred for duplicate negatives, and should receive a polysulfide treatment. Diazo and vesicular films, which are cheaper and less prone to scratching than silver films, are often used for service copies. Duplicate films are inspected for resolution, density, and completeness as required in ANSI/AIIM and RLG standards and guidelines.


• Return of Film and Originals to the Institution—Original materials are generally returned at the same time to facilitate in-house inspection of the film, but master negatives should never be shipped in the same box, or on the same day, with their service copies or duplicate negatives. If possible, master negatives should be shipped by the vendor directly to off-site storage.


• Post-filming Activities—You must conduct in-house quality control inspections once the film is returned. These should include a general inspection of the film, packaging, and labeling, as well as a more comprehensive technical inspection that might include testing for density and resolution, as well as scratches, problematic splices, and other problems.


• Storage—Once materials have been filmed, house all preservation microfilm in archival enclosures, maintain microfilm readers regularly, and insist that researchers use the microfilm instead of the original materials. Master negatives must be stored off-site, preferably under the proper temperature and humidity conditions.

At the beginning of a project, ask the filmer to return the first few rolls as soon as they are finished so that you can inspect them and make sure that your expectations are being met.