LASER STAIN REMOVAL OF FUNGUS-INDUCED STAINS FROM PAPERHANNA MARIA SZCZEPANOWSKA, & WILLIAM R. MOOMAW
ABSTRACT—Artworks and other documents on paper often suffer damage from the growth of several species of fungi. These fungi appear to utilize trace mineral elements in the paper for their metabolism and gradually consume the paper itself as a carbon source. In the process, they often produce stains on paper that may arise from colored, organic metabolic waste products, or the fungus may convert colorless metal ions in the paper into visible stains, as occurs in foxing. Sometimes the observed stain is that of the colored fungal bodies themselves. In this paper, we will report on the effectiveness of the intense light from a powerful laser to remove fungus-produced stains from prints, drawings, and artworks executed on paper. In some favorable cases, the fungal mycelia that penetrate the paper were removed along with the stain. Examination of successfully treated areas by both optical and electron microscopy reveals little or no damage to the surface or structure of the paper support following laser cleaning. Care must be exercised to avoid burning the paper with the laser beam or removing ink or pigment from the artwork itself. When used appropriately, laser removal of fungal stains and residue appears to have considerable potential for nondestructive conservation of works on paper.
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