An X-ray photoelectron spectroscopic study of ancient paper and its deterioration

Studies on the deterioration of medieval paper, in particular on the widespread foxing and discoloration which affects sheets, have attributed the origin of these phenomena to trace elements within the paper itself and/or to the action of external agents. This investigation was carried on the possible correlation between the process of manufacturing and paper deterioration. Attention was focused particularly on the chemical nature of the sizing, such as animal gelatin, vegetal polysaccharides, such as starch, and on the procedure itself used for the sizing. Since sizing is a technique which affects mostly the surface of a sheet, we used X-ray photoelectron spectroscopy as this is an extremely sensitive method for studying surface phenomena. X-ray photoelectron spectroscopy is an ideal analytic tool for measuring the chemical composition of the first few layers of all solid materials. This paper proposes the use of this technique to estimate the effect of sizing on the preservation of paper sheets produced in Europe between the 15th and the 18th centuries.