Blanching of unvarnished modern paintings: a case study on a painting by Serge Poliakoff.

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Publication Type:

Conference Paper

Authors:

Koller, J.; Burmester, A.;

Source:

Cleaning, retouching and coatings: Contributions to the 1990 IIC Congress, Brussels, p.138-143 (1990)

Keywords:

beeswax, blanching, blooming, fatty acid, gas chromatography-mass spectrometry, light, Modern, oil painting, oxidation, oxygen, paint, Poliakoff, Serge (1900-1969), unvarnished, white spirit

Abstract:

Oil paintings by Serge Poliakoff (1900-1969) show a remarkable tendency towards surface blanching. The blanching effect is caused by a whitish blooming, covering parts of the surface. As the paintings of Poliakoff are composed of sharply delimited monochrome geometrical areas, different intensities of blooming could be distinguished related to the type of pigmentation. Gas chromatography/mass spectroscopy (GC-MS) analyses revealed that the paint layers contain a lot of free fatty acids. This mixture of unsaturated liquid and saturated solid fatty acids migrates to the surface. All unsaturated fatty acids will be degraded by oxidation on the unvarnished surface under the influence of oxygen and light and only the saturated fatty acids remain on the surface as whitish blooming. A treatment with beeswax dissolved in white spirit was applied. No new blooming has been observed two years after this conservation measure.