A Study on the Retouching Materials for Oil Paintings - Using Restoration Colors and Acrylic Gouache -

Abstract

In this study, we compare the properties and estimate the durability of five oil colors that are the most popularly used colors in the conservation of oil paintings. A set of these colors was obtained form four manufacturers each, and their properties were analyzed by conducting deterioration experiments. Subsequently, we observed the colors and performed X-ray fluorescence analysis. As a result of colour observation and XRF analysis, it was confirmed that there are the differences according to the pigment types, mixing rations and the manufacturers even for colors having the same product name. The deterioration test indicated differences in the appearance of the colors ; for instance, the color difference was above 12.0 in most of the samples, including restoration color and acrylic gouache. In the case of Lemon Yellow a lot of discoloration and cracking occurred, and difference in gloss was ob served in Viridian of manufacturer C. Most cracks were ob served in the restoration color obtained from manufacturer B and were assumed to be because of the resin used by the manufacturer. Nevertheless, additional research will have to be conducted by controlling variables in order to find out the cause. Through this study, we demonstrated that retouching materials for conservation of oil painting differed in their physical properties according to the color and manufacturer. Therefore a conservator should be mindful during the selection and use of materials for retouching oil paintings.