Background: In 1994, the American Society for Testing and Materials (ASTM) and its Institute for Standards Research (ISR) initiated a five-year inter-laboratory research program on the aging of printing and writing papers, supported by 33 institutions in the paper industry, academia, and the library and archive community. The goals of the program were to develop new accelerated aging test methods, which were to model the chemical and mechanical effects of natural aging as closely as possible. Fifteen model papers were custom made for the study to provide well-characterized acidic and alkaline test specimens, with fiber contents representative of contemporary and historic printing and writing papers. Five laboratories conducted this work, investigating the impact of elevated temperature, elevated light flux, and elevated concentration of common atmospheric pollutant gases. The Library of Congress Preservation Research and Testing Division performed research on the impact of elevated temperature at constant paper moisture content, and investigated the effect of different physical presentation of papers in the accelerated aging chamber.
Contributing Studies:Shahani, C.J.; Lee, S.B.; Hengemihle, F.H.; Harrison, G; Song, P.; Sierra, M.L.; Ryan, C.C.; Weberg, N. Accelerated aging of paper: I: Chemical analysis of degradation products, II: Application of Arrhenius relationship, III: Proposal for a new accelerated aging test. Preservation Research and Testing Division, Library of Congress, Washington, DC; June 2000. American Society for Testing and Materials Research Report (RR#) D06-1006 .
American Society for Testing (ASTM) standards: Adopted in Volume 15.09, 2002
D 6819-02, Test Method for Accelerated Temperature Aging of Printing and Writing Paper by Dry Oven Exposure Apparatus
D 6833-02, Test Method for Accelerated Pollutant Aging of Printing and Writing Paper by Pollution Chamber Exposure Apparatus
D 6789-02, Test Method for Accelerated Light Aging of Printing and Writing Paper by Xenon-Arc Exposure Apparatus
Shahani, C. J., Harrison, G.; "Spontaneous Formation of Acids in the Natural Aging of Paper." Works of Art on Paper, Books, Documents and Photographs: Techniques and Conservation. Contributions to the Baltimore Congress, 2-6 September 2002. International Institute for Conservation, London, 2002. p.189-192.
Shahani, Chandru. "Accelerated Aging of Paper: Can It Really Foretell the Permanence of Paper." Proceedings from the ASTM/ISR Workshop on the Effects of Aging on Printing and Writing Papers. Philadelphia, PA July 1994. [PDF: 326 KB / 18 p]
Arnold, B. "ASTM Paper Aging Research Program." The Book and Paper Group Annual Vol 19, Shannon Zachary, Ed, American Institute for Conservation, Washington D.C., 2000.
Arnold, R. Bruce; Chair: ASTM Paper Aging Research Program; R. B. Arnold Associates, Inc. ASTM's Paper Aging Research Program.
Project Description: The research performed by the Preservation Research and Testing Division staff involved Arrhenius-type studies of six papers that modeled a range of paper stability:
- a highly stable cotton-fiber paper, both acidic and alkaline;
- a medium-stability bleached northern softwood Kraft paper, both acidic and alkaline; and
- a low-stability stone ground wood paper, both acidic and alkaline.
The research method utilized free-hung sheets, stacks of sheets in humid ovens, and sheets that were pre-conditioned at 23ºC (73ºF) and 50% RH and then heat-aged in hermetically sealed glass tubes. Accelerated aging tests were conducted at four temperatures ranging from 60° – 90°C, at humidity levels selected to maintain consistent moisture content across all test conditions. Mechanical and chemical data were collected for the aged test papers and analyzed to determine the impact of physical presentation and temperature variations on the reaction kinetics.
Test methods incorporated the use of two chromatographic methods to obtain chemical “fingerprints” of the organic compounds formed as the result of the different aging protocols. The chemical fingerprints from the accelerated aging studies were compared to those from naturally aged papers.
Outcomes/Findings: There were several important findings from this research:
- Chemical analyses reveal that small organic acids form spontaneously in the aging of all cellulosic papers, including highly stable cotton papers and alkaline papers, even at room temperature.
- Chemical fingerprints of the degradation products formed as a result of natural vs. accelerated aging are similar, with the greatest similarity to naturally aged papers seen in the test papers conditioned at 23ºC and 50% RH and then heat-aged within airtight glass tubes.
- Arrhenius relationships show no detectable changes in the reaction mechanisms across the range of elevated temperatures studied. However, aging data obtained at these high temperatures cannot be extrapolated accurately to ambient (room temperature) conditions, as supported by results from the Canadian Conservation Institute (CCI).
- Data from Arrhenius plots and chemical analyses show that accelerated aging of paper samples conditioned at 23°C and 50% RH, and then aged inside an airtight glass enclosure at an elevated temperature, models natural aging better than aging either as loose sheets (normal practice) or in book-like stacks.
- The project highlighted the need for well-documented natural aging studies, to compare to accelerated laboratory tests. ASTM subsequently initiated a 100-year natural aging study, using the fifteen model papers created for this project.
Support: ASTM Institute for Standards Research
Acknowledgements: Canadian Conservation Institute, USDA Forest Products Laboratory, Image Permanence Institute at Rochester Institute of Technology, Oy Keskuslaboratorio Centrallaboratorium Ab (Espoo, Finland).
Update and Images:
Summer 2011: the remaining stocks of paper produced for this project were integrated into the Center for Library and Analytical Scientific Samples (CLASS).
Papers prepared for oven aging in different physical formats: stacks, loose
hanging sheets,
sealed tubes with strips or shredded pieces.
