1 INTRODUCTION

This review looks at published sources of information regarding Paraloid B-72 and its role in consolidating stained glass, with particular reference to reattaching lifted or unstable paint layers. The aim is to comment on and evaluate recent trends in stained glass conservation practice. Paraloid B-72 has commonly been used to consolidate glass, either alone or in combination with other resins, since the early 1980s. In the museum environment, it is highly regarded as an adhesive for its strength, stability, and reversibility (Koob 1986; Horie 1987; Koob 2000). The ease with which the properties of the resin can be adapted to suit different circumstances by the addition of different types and quantities of solvent has made it a popular choice with conservators. It may, however, be more harshly tested in an architectural situation, where it may be subject to greater extremes of humidity, temperature, and UV radiation, and the resin may possess additional practical limitations as far as the treatment of stained glass is concerned. This study attempts to review and assess, based on sources available in the literature, the suitability of Paraloid B-72 for the treatment of architectural stained glass.

The application of advanced scientific techniques to the study of the behavior of consolidants for different types of stained glass under artificial aging conditions has been largely a Franco-German endeavor. The last 10 years have seen a proliferation of literature on this subject and on the development of new materials specifically suited to the consolidation of glass (Romich et al. 1993; Programme Franco-allemand 1999; Wolff 2000), the salient features of which are reported here. The outcomes of these important and extensive studies—in particular the potential for development of new inorganic and hybrid consolidation products such as silicon-zirconium alkoxides (SZA) and ORMOCER—remain to be tested and observed in the practical domain.

By contrast, empirical approaches to the treatment of objects on-site or in the laboratory, work-shop, or studio, practical experiences with consolidant products, and reviews of previous treatments are rarely reported in the literature of stained glass conservation. Wherever possible, provision should be made to disseminate this documentation more widely. This move would greatly assist researchers of the future, whose task it will be to evaluate past treatments, optimize existing systems, and enhance the properties of new products.