Ozone and the deterioration of works of art

Seventeen artists' watercolor pigment samples and two Japanese woodblock prints were exposed to 0.40 ppm ozone in a controlled test chamber for three months. It was found that several artists' pigments when applied on paper will fade in the absence of light if exposed to an atmosphere containing ozone at the concentrations found in photochemical smog. Alizarin-based watercolors containing 1,2 dihydroxyanthraquinone lake pigments were shown to be particularly sensitive to ozone damage, as were the yellow pigments used in the Japanese woodblock prints tested. Indoor-outdoor ozone monitoring in a Pasadena, CA art gallery confirmed that ozone concentrations half as high as those outdoors can be found in art galleries that lack a chemically protected air conditioning system. Care should be taken to protect works of art from damage due to photochemical smog

Protection of Works of Art From Atmospheric Ozone

Assesses the colorfastness of organic colorants and watercolor pigments tested in atmospheric ozone. A summary of a full report of the Environmental Quality Laboratory, California Institute of Technology, Pasadena

Fading of artists' pigments due to atmospheric ozone

Recently, it has been shown that several artists' pigments will fade in the absence of light if exposed to atmospheric ozone at the levels found in Los Angeles photochemical smog. In the present study, a large number of artists' organic watercolors have been examined to further assess the scope of this fading hazard to works of art. Twenty-seven organic watercolors were exposed to 0.31 ± 0.12 ppm 0_3 at 46 ± 6% relative humidity for 90 days. It was found that all of the watercolors containing alizarin derived pigments (1, 2-dihydroxyanthraquinone lakes) are susceptible to fading in the presence of ozone. A number of pigment blends containing at least one ozone fugitive chemical component were found to change their apparent color after exposure to ozone. Several organic red pigments that are much more ozone resistant than the alizarin lakes, including quinacridone reds and BON arylamide reds were identified. This information may aid artists in selecting more durable substitutes for the ozone fugitive alizarin lakes

The Ozone Fading of Traditional Natural Organic Colorants on Paper

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

The Ozone Fading of Traditional Natural Organic Colorants on Paper

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

The measurement and model predictions of indoor ozone concentrations in museums

Eleven museums, art galleries, historical houses and a museum library were monitored for 38 days during the summers of 1984 and 1985 to determine whether high outdoor ozone concentrations are transferred to the indoor atmosphere of museums. Museums having conventional air conditioning systems show peak indoor ozone concentrations about 30–40% of those outdoors. Buildings with no air conditioning but a high rate of air exchange with the outdoors show peak indoor ozone levels 69–84% of the outdoor concentrations, while other buildings where slow air infiltration provides the only means of air exchange have indoor ozone levels typically 10–20% of those outdoors. Indoor ozone concentrations as high as 0.143 ppm were found in one museum that lacks a chemically protected air conditioning system. For purposes of comparison, the recommended ozone level in places where works of art and historical documents are stored ranges from 0.013 to 0.001 ppm depending on the authority cited. A mathematical model was used to study the ozone concentrations within these buildings to confirm that the differences in indoor ozone levels between buildings can be explained in terms of building and ventilation system design

Ozone Fading of Triphenylmethane Colorants: Reaction Products and Mechanisms

Triphenylmethane compounds were exposed in the dark to ozone in air (10 ppm for 4 days), and the exposed samples were analyzed by mass spectrometry. There was no evidence for reaction between ozone and triphenylmethane and between ozone and the triphenylcarbinol pararosaniline base. In contrast, the triphenylmethane cationic dye Basic Violet 14 yielded substituted benzophenones and other aromatic compounds. These products are consistent with a mechanism involving ozone addition on the unsaturated carbon-carbon bond. The results are briefly discussed in terms of the ozone fastness of triphenylmethane dyes used as artists' pigments and industrial colorants

The measurement and model predictions of indoor ozone concentrations in museums

Eleven museums, art galleries, historical houses and a museum library were monitored for 38 days during the summers of 1984 and 1985 to determine whether high outdoor ozone concentrations are transferred to the indoor atmosphere of museums. Museums having conventional air conditioning systems show peak indoor ozone concentrations about 30–40% of those outdoors. Buildings with no air conditioning but a high rate of air exchange with the outdoors show peak indoor ozone levels 69–84% of the outdoor concentrations, while other buildings where slow air infiltration provides the only means of air exchange have indoor ozone levels typically 10–20% of those outdoors. Indoor ozone concentrations as high as 0.143 ppm were found in one museum that lacks a chemically protected air conditioning system. For purposes of comparison, the recommended ozone level in places where works of art and historical documents are stored ranges from 0.013 to 0.001 ppm depending on the authority cited. A mathematical model was used to study the ozone concentrations within these buildings to confirm that the differences in indoor ozone levels between buildings can be explained in terms of building and ventilation system design