1 INTRODUCTION

The importance of the interaction of environment and collections was recognized long before the then Keeper of the British Museum Research Laboratory published The Conservation of Antiquities and Works of Art (Plenderleith 1956). This book contains a section on “The Influence of Environment” based on research on the deterioration of objects in the collection carried out by the Museum scientists between 1922 and 1950. By today's standards the information is rudimentary, but it did give useful guidance on collections care. In parallel to the work at the British Museum, research into the effects of the environment on oil paintings and on Japanese art was being carried out in other institutions. This work informed two important publications, The Museum Environment (Thomson 1978) and Characteristics of Japanese Art that Condition Its Care (Toishi and Washizuka 1987), both of which have contributed to the framework of what has become known as preventive conservation.

In the early 1970s, under the leadership of A. E. A. Werner, British Museum conservation scientists began a concerted program of research into the effects of the environment on the collection. This research was driven by the development of new galleries and the need to establish whether or not control of temperature and/or relative humidity was needed to safeguard the objects, to justify its inclusion in the projects.

There were several reasons not to attempt largescale climate control. First of all, being designated grade one listed by English Heritage means that the British Museum building is of such historical importance that it should be maintained in its original form. Putting in air conditioning for galleries without affecting the structure is very costly, aside from the expense of installation, running, maintenance, and replacement of the systems. Secondly, the trend was away from single-object galleries, such as the run of upper floor galleries displaying Greek pottery, to thematic mixed-object galleries where no one environment would be suitable for all of the objects. Finally, much of the collection is stable in the ambient conditions in the Museum and air conditioning was simply not needed. Hence, simple approaches and targeted control were favored for the display and storage of those objects which were found likely to deteriorate in normal ambient conditions.

The research focused on single objects or groups of objects which were deteriorating, to identify the cause and a method of prevention. The role of relative humidity soon became apparent. Determining an appropriate relative humidity and suitable method of control was part of the prevention strategy. Gases given off by the materials used in storage and display, and sometimes given off by the objects themselves, were found to cause corrosion of metal objects and to form mixed salts on the surface of some porous stone and ceramic objects.

In this paper an overview of the research between 1970 and 2005 on temperature, relative humidity, and pollutant gases is put in the context of the development of preventive conservation practice in the British Museum.