Microfilm shall be of the type suitable for archival quality. Archival quality or permanent film is defined as any film that is equal to or better than silver-gelatin film, as specified in the “American National Standard for Imaging Media (Film)—Silver-Gelatin Type—Specifications for Stability (ANSI/NAPM IT9.1-1992)” and in the “American National Standard for Photography—Determination of Regional Thiosulfate and Other Related Chemicals in Processed Photographic Materials—Methods Using Iodine—Amylose, Methylene Blue and Silver Sulfide (ANSI/NAPM IT9.17-1993)”, which are incorporated by reference. Diazo or vesicular film are not acceptable as archival quality microfilm. If an agency is microfilming its own records, it shall be the responsibility of the head of each agency or office to ensure that microfilm equipment is cleaned and maintained according to manufacturer's specifications or accepted industry practice, or both. Microfilm Processing Requirements. For the production of archival quality or permanent film, microfilm shall be processed as described in this section. Permanent text records shall be microfilmed at a reduction ratio not greater than 24X. Permanent graphic records shall be microfilmed at a reduction ratio not greater than 36X. Each film roll shall contain not less than 18 inches of film leader, and 18 inches of film trailer. Microfilm Density. Optimum background densities of microfilm images are dependent upon the quality of the documents filmed. For permanent records, density on negative copies will be between 0.95 and 1.2. For nonpermanent records, the ultimate density criterion is that the microfilm be legible for its intended use (reading, copying, or production of hard copy), and that all images on a roll can be printed, as much as is practicable, at the same printing exposure. The following classification indicates the maximum limits of density: Density not higher than 1.4 is required for high quality printed books, periodicals, and dense typing; Density not higher than 1.3 is required for fine line originals, letters typed with a worn ribbon, pencil writing with a soft lead, and documents with small printing; Density not lower than 1.0 is required for pencil drawings, faded printing, graph paper with pale fine colored lines, and very small printing such as footnotes; Density not lower than 0.8 is required for very weak pencil manuscripts and drawings, and poorly printed, faint, or faded documents; and Readings beyond these densities are unacceptable. Resolution of the completed microfilm may not be less than 100 lines per millimeter, as determined by inspection of a resolution test chart photographed on each roll of film. Residual thiosulfate concentration shall be less than 1 microgram per square centimeter as proved by subsequent testing of the processed film. At regular intervals agencies shall send samples of processed film to the Division's Microfilm Laboratory for methylene blue testing. Samples are to be processed within 1 week before testing if accurate results are to be obtained. The following identification targets, presented in the order in which they are to appear, shall be used on each roll of microfilm: Resolution test target for rotary camera applications derives from the “Standard for Information and Image Management—Practice for Operational Procedures/Inspection and Quality Control of First-Generation Silver Microfilm of Documents, Rotary Camera Test Chart (ANSI/AIIM MS 23-1991)”, which is incorporated by reference, or for planetary camera applications “Photographic Microcopy Target (NBS 1010a)”, which is incorporated by reference; A title target for each volume of records to be filmed shall include the agency name and the record title and volume identification, both identifiable without the use of a magnifier or viewer; A certification target signed by authorized agency personnel; Certificate of Camera Operator Target (RM-4); and The appropriate test chart. During filming, if any document is suspected of not having been filmed correctly, follow that image with a correction target, followed by the document again. After exposure, each roll of microfilm is developed and inspected to insure completeness and legibility of every image. A light box inspection alone is not acceptable. Illegible or missing records shall be microfilmed again as retakes, according to the following procedure: Allow 18 inches of blank leader at the beginning of the retakes for each individual volume; Photograph a start of retake section target; Microfilm the documents that were illegible or missing in the same order in which they would have appeared on the original roll if they had been available; Microfilm an end of retake section target; Allow 18 inches of blank trailer at the end of each section of retakes; and After processing, inspection, and approval, splice retake images onto the beginning of the original roll of microfilm that bears the illegible images or lacks the documents contained on the retake roll. Precautions shall be taken in the handling and storage of original camera microfilm. These precautions include, but are not limited to, the following: Always wear cotton gloves when handling film to prevent fingerprints or dirt on the microfilm images; Never use tape, paper clips, rubber bands, staples, etc., to splice or hold microfilm on rolls or any other microform; Do not place microfilm on reels that corrode or emit toxic elements that destroy microfilm; and Do not store microfilm within 4 inches of the floor because storage under improper conditions of temperature and humidity drastically shortens the useful life of microfilm; Recommended standards for temperature and humidity for the storage of microfilm are as follows: Short-term (under 10 years) storage temperature may not exceed 75°F and relative humidity may not exceed 60 percent, and Permanent or archival storage temperature may not exceed 70°F and relative humidity may not exceed 40 percent. Archival microfilm of records scheduled for permanent retention shall be transferred periodically to the Archives. This microfilm shall be the silver-gelatin master negative.