1 INTRODUCTION

MANY MODERN PAINTINGS cannot be cleaned in the traditional manner because their surfaces—either paint or fabric—are sensitive to liquids of any kind. Paintings whose surfaces include exposed areas of unprimed, raw cotton duck, such as works by Helen Frankenthaler, Kenneth Noland, Morris Louis, and Jules Olitski, present difficult cleaning problems for the conservator. The application of a swab moistened with saliva, water, or solvent could alter these surfaces by dissolving some portion of them or some material on them, thereby darkening or otherwise discoloring the area. In order to remove particulate soiling from these kinds of surfaces, painting conservators have had recourse to procedures and techniques used in other conservation fields. Among those is the use of erasers and products developed for wallpaper cleaning. However, a variety of issues need to be addressed when using erasers. These center around the composition of the eraser and its abrasive action on the textile as well as the quantity, color, size, and tenacity of the crumbs left on the surface. In addition, the effect over time of the eraser residue on the fabric's pH, color, and brightness over time needs to be considered if all the crumbs are not able or likely to be removed.

This study was designed to evaluate seven dry cleaning products and their effects on cotton duck (see table 1). Erasers may have also found use on the painted surfaces of art, but due to the complexities and varieties of paint composition, the effect of erasers on these types of layers will not be considered in this paper.

Table 1 Erasers Studied

While the paper conservation literature has recommended a variety of erasers over the past eighteen years, and investigations and analyses of varying scientific rigor have been carried out on several of these products, no research as to their effect on a canvas support has been published to my knowledge. The seven erasers chosen for this study are, for the most part, easily available and likely to be found in conservation studios. Several have been included in paper conservation studies, and, therefore, some of their properties have already been described.1

The experiment undertaken involved treating strips of unaged and preaged cotton duck with the erasers and then aging them further for different periods of time. A qualitative assessment of the abrasive effect of the erasers and of the quantity and tenacity of crumbs remaining on the surface was made. Brightness, color, and pH measurements of the textile samples were taken. Surface and cold extraction pH measurements of the unaged erasers themselves were also taken.