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Published 1987 | public
Journal Article

The Ozone Fading of Traditional Natural Organic Colorants on Paper

Abstract

This report details the results of an ozone exposure experiment performed on a large number of traditional natural organic colorants applied to watercolor paper with no binder. These colorants were exposed in an environmental chamber to an atmosphere containing 0.397 ± .007 parts per million (ppm) ozone at 72°F and 50% RH in the absence of light for 12 weeks. This ozone concentration is typical of that found in the Los Angeles atmosphere during a heavy smog episode. The total ozone dose delivered to the samples is equivalent to about four years of exposure to outdoor air in Los Angeles or to about eight years inside a typical air conditioned building in Los Angeles. The ozone sensitivity of these colorant systems was evaluated by monitoring the color changes which occurred during the exposure. Almost all colorant systems tested showed some degree of fading after ozone exposure, and a few of these (curcumin, dragon's blood, indigo, and madder lake) should be considered very ozone-fugitive.

Additional Information

© 1987 Taylor & Francis, Ltd., Maney Publishing. This research was performed under a contract with the Getty Conservation Institute, and this article is based on a paper presented at the 14th Annual Meeting of the American Institute for Conservation in Chicago, Illinois, 21-25 May 1986. Natural colorants were made available with the cooperation of Eugene Farrell and Richard Newman of the Harvard University Art Museums, and Gary Wade Alden, of the Balboa Art Conservation Center. The Munsell conversion calculations were performed using a computer program supplied by Max Saltzman and Dr. Fred Billmeyer. Discussions with Mr. Saltzman were helpful in the spectro- scopic analyses of the pigments. The authors also wish to acknowledge the assistance of Dr. Helmut Schweppe, whose advice and reference materials aided the thin layer chromatographic identification of the natural colorants.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023