ANALYSIS OF PIGMENTS USED IN SCROLL PAINTINGS OF A NATIONAL TREASURE 'TALE OF GENJI' USING A PORTABLE X-RAY FLUORESCENCE SPECTROMETER

摘要

X-ray fluorescence spectrometry (XRF) is frequency applied for thernmeasurement of the chemical composition of cultural properties because of its rapidityrnand non-destructiveness. However, it is hard to analyze a sample at the site byrnconventional XRF. In order to solve this problem, a portable XRF has been developed.rnThe pigments used in the Scroll Paintings of the Tale of Genji in the possessionrnof the Tokugawa Art Museum have been analyzed by portable XRF. This instrument wasrnbrought into the museum to avoid various risks that may be caused by moving thernpaintings. The Scroll Paintings of the Tale of Genji are considered as most important inrnunderstanding the materials and techniques of painting in the 12th century. The pigmentsrnused in the fifteen illustrated sheets in the museum were once estimated by anrnexamination using X-ray radiography and ultra-violet fluorescence spectroscopy in 1950-rn1954. However, the elements and the compounds of the pigments have not beenrnidentified yet.rnIn this study, the elements of the pigments were measured by using an X-rayrnbeam with Φ2mm diameter. As a results of measurement of about 20-30 points per eachrnillustrated sheet, composition of pigments corresponding to different colors werernidentified. For example, 4 kinds of white pigment were detected; major component arern(1) Pb (2) Ca (3)Hg (4) not detectable. It was also made clear that the white pigmentsrnconsisting mainly of Pb used for drawing a human face contains a trace of Hg.rnFurthermore, the color used for drawing the human face was slightly different betweenrnillustrated sheets. This study might give some understanding the material and techniquesrnof painting in the 12th century.rnIn conclusion, this portable XRF analyzer is a powerful tool for non-destructiverninvestigation of cultural properties.