Permanence of Photocopy Images

• In ASTM, a subcommittee of Committee F-5 on Business Imaging Products is working on a guide to photocopy permanence that will appear in a few years. It will include the abrasion test, the hard crease test, and possibly others. (The test target is available now, on paper and in software that will generate it on machines being tested. Contact Theodore Wirth, Chair of F-5, at Industry Analysts, Inc., Technical Services Division, 201/227-8699.) The subcommittee is F05.04 on Electrostatic Imaging Products.

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• ISO/TC 46/SC 10/WG 2 (International Organization for Standardization, Technical Committee 46, Subcommittee 10, Working Group 2, on Permanence of Images on Paper), focuses on the image-paper combination. They are evaluating it for image color strength and appearance, light fastness, water resistance, blocking under heat and pressure, resistance to tear, heat resistance and the effect of the image on the mechanical strength of the paper. At its meeting last May, the Working Group looked at the optical density of the image resulting from the various copying and writing methods. Heat resistance will be measured by standard accelerated aging tests. Round robin testing in a number of labs was planned to begin in September 1994.
• Imaging Products Monthly for May 1994 has a list of toner binders on p. 10-11, assembled by John Cooper, head of Toner Research Services, Inc. (Black Mountain, NC, 704/669-0510, fax 669-0910). It shows which toner binders are used by each of 60 toner manufacturers. The binders used by most companies, if you don't count "miscellaneous," the largest category, are styrene acrylic and wax. Next comes polyester, then styrene butadiene and acrylic. Those used by fewest companies are epoxy, EVA, polyamide, and polystyrene. (These binders are not specific compounds, but families of compounds, the members of which may differ from each other considerably.) The variety and complexity of this picture make it clear how hard it is to generalize about the permanence of toners on the basis of the materials used in their manufacture.

Two references on the permanence of photocopies, for people who missed them the first time around, are:

• Restaurator v.8 #1, 1987. Special issue: Preservation Photocopying in Libraries and Archives: Conference of the U.S. National Archives and Records Administration, Washington, DC, Dec. 9, 1986. One paper addresses the permanence of photocopies directly: Sylvia S. Subt: "Archival Quality of Xerographic Copies," p. 29-39. Fourteen copying systems were examined; most failed one or more tests, though the Kodak Ektaprint 85 system passed all of them. Subt has seven "conclusions and recommendations," which advise against stacking photocopies under any great pressure (because the toners flow slowly even without heat, and this makes them stick together). She also warns against storing copies next to vinyl. She says to use archival quality paper and to keep the machine well maintained to ensure that the temperature is right for fusing the toner to the paper. The tape peel and rub tests are recommended for on-site copy evaluation techniques.
• Archival Copies of Thermofax, Verifax, and Other Unstable Records, by Norvell M.M. Jones. National Archives Technical Information Paper No. 5. National Archives & Records Administration, Washington, DC, 1990. $17.50 + $4 handling, prepaid, from National Technical Information Service, Springfield, VA 22161 (703/487-4600). PB 90 171 836. 28 pp., including the 1987 appendix by S. Subt and J. Koloski that describes the tape peel and rub tests.
• In addition, two ASTM standards relate to this subject. ASTM D 3458 - 85, which was reapproved in 1990, focuses on the paper, but is vague about the permanence of the image. Another standard is being worked up by the business imaging committee, F 5, and will be announced when it is ready. It may or may not address the topic of keeping photocopied images for periods longer than a few decades.