Preservation

Microfilm - Preservation [TXM-P1]

Record Type
Expected Use Preservation Master
Product Name Microfilm - Preservation [TXM-P1]
Product Purpose

The purpose of this product is to mitigate risk for loss of information. This product is at an appropriate information capture level to substitute for the original record if the original record copy is no longer viable.

Nature of Source Material

The highest quality digital preservation or reproduction master file produced.

Film Stock

Polyester-based silver gelatin type film that conforms to ANSI/NAPM IT9.1—1996 for LE 500 film

Other Information
  • This product is stored in climate controlled conditions off site and is not accessed directly unless the microfilm legacy printing master (if one exists) or digital reproduction master is damaged or destroyed or otherwise compromised.
  • This product conforms to NARA CFR1230 Subpart C Microfilm Standard.
Quality Control Quality Assurance and Quality Control for Microfilm Products
  • Microfilm products conform to the NARA CFR1230 SubPart C: Microfilm Standard
  • Film Processing
    • Black and White Film
      • B&W processing is conducted in-house.
    • Methylene blue testing (implementation underway)
      • ISO 18917 1999 compliance: Methylene blue testing to measure residual thiosulfate and its decomposition products is of use in appraising the adequacy of washing and therefore the permanence of the silver image on photographic films, plates and papers. Inadequate washing can cause a loss in image density and the formation of stain in low-density areas.
Rationale

While the capture process for most original photograph, text-based and object/artifact original source material record types is file-based and results in digital products, there are limited options for hard copy outputs. The first is aerial photonegative prints. While digital capture specifications are established for aerial photo negatives and film positives, this workflow remains an analog-to-analog film duplication process at this time. The lab expects to transition to analog-to-digital workflow in the future. A second area is microfilm. Polyester-based silver gelatin microfilm is generated from digital preservation master files for text and cartographic collections captured in the Photographic Imaging, Microfilm and Textual Preservation Lab and then stored off-site in a climate controlled limited access vault. In addition, polyester-based silver gelatin microfilm copies are available for the Microfilm Publications beginning with the M, P. C or T prefix. Third, there is a very limited option to produce facsimile prints from digital files for specifically identified purposes only.

Currently, the digital distribution copy options are generally the same for all still images regardless of the format of the original source material.

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The U.S. National Archives and Records Administration
1-86-NARA-NARA or 1-866-272-6272

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