Beneath the Surface: Understanding Paint Analysis in Historic Houses by Christine Leback Sitwell The National Trust is responsible for the care of over 200 historic houses and their collections in England, Wales and Northern Ireland. The houses represent a range of examples of architectural styles with many diverse interiors which are either contemporary with the period of the house or reflect the stylistic changes that occurred and, in some instances, reveal the individual owner's idiosyncrasies. Traditionally, the Trust has used "paint scrapes" (the mechanical exposure of paint layers) in combination with archival information and known research on historic interiors to formulate its approach to the redecoration of decorative schemes. The use of "paint scrapes" provides information about past colour schemes but lacks precision in that thin paint layers, glazes and toned varnishes may accidentally be removed during the mechanical process of scraping. The introduction of paint analysis (the microscopic and analytical examination of paint samples) offers a more precise tool for the understanding of the complete sequence of paint and varnish layers and the identification of pigments by analytical analysis for dating purposes and colour rendering. The paint cross sections also provide information about the condition of the underlying layers and, this information combined with small cleaning tests, can determine whether or not it is feasible to remove the overlying layers thus revealing earlier surfaces. Where applicable, conservation techniques have been used for the removal of these overlying layers of paint. These methods have encouraged the National Trust to consider the feasibility of revealing earlier paint schemes rather than simply recreating a scheme by repainting. Documentation is an important part of any project and with historic interiors it is essential that all information whether archival or technical is recorded not only for a clearer understanding of the development of an interior but also for use by future generations. For a large organisation, retrieval and accessibility are essential so, in conjunction with this work, a database has been developed to document the results of paint analysis as well as all other relevant information about the decorative schemes. In addition, a spectrophotometer is used to record colours of existing schemes and new schemes to provide a more accurate means of colour measurement. The National Trust has always been cautious in its approach to the redecoration or interpretation of historic interiors and exteriors because their decorative histories are often complex. However, the use of paint analysis and conservation techniques enables the Trust to tackle the more challenging interiors and exteriors either to document, recreate or, where possible, reveal earlier schemes. These methods are tools that in conjunction with archival and historical knowledge play a role in the collaborative decision making process. The ability to access information through the database should enable the Trust to undertake comparative studies of decorative styles and their materials and techniques. The Chinese House at Stowe and the Adam Library at Nostell Priory are two examples which show not only the collaboration between the Adviser on the Conservation of Painted Surfaces, the Architectural Historian and the Curatorial staff of the Trust; but also the use of paint analysis in the understanding of the decorative surfaces leading to their preservation or recreation. Back to conference agenda