Scanning electron microscopy techniques for imaging materials from paintings

Abstract

This chapter reviews a range of techniques of scanning electron microscopy (SEM), and its application to the study of paintings and artists materials. SEM has been almost universally applied for the surface characterization of materials from art and archaeological objects. The review focuses on imaging the materials (rather than chemical analysis), and its application to the materials used for and from easel paintings. Examples of published experimental studies of cleaning, paint surface defects, biodeterioration of painting materials from the conservation and paint manufacturers literature are discussed, with reference to sample preparation and imaging conditions. Images of selected artists materials and materials from paintings examined using conventional high vacuum SEM, low vacuum (variable pressure) SEM and ESEM are given to illustrate comparative techniques. Electron microscopy offers higher magnification combined with significantly better resolution than the light microscope that has been traditionally used to examine the surface and layer structure of paintings, and provides magnifications up to the range of lOOOx. The magnification is limited by the wavelength of light. The potential for high magnification is advantageous, especially in the examination of problems where illustration of fine topographical features helps to understand gross effects, or in the detection of changes that may occur as the result of a specific treatment beyond resolution of the light microscope.