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Conservation of Easel Paintings, Second Edition provides a much-anticipated update to the previous edition, which has come to be known internationally as an invaluable and comprehensive text on the history, philosophy and methods of the treatment of easel paintings.Including 49 chapters written by more than 90 respected authors from around the world, this volume offers the necessary background knowledge in technical art history, artists’ materials and scientific methods of examination and documentation. Later sections of the book provide information about the varying approaches and methods for treatment and issues of preventive conservation, as well as valuable reflections on storage, shipping, and exhibition. Including exciting developments that have taken place since the last edition was published, the book also covers new techniques of examination, especially MacroXRF scanning and Reflectance Transmission Imagery. Drawing on research presented at recent professional conferences, information about innovative methods for cleaning modern and contemporary paintings and insights into modern oil paints is also included.Incorporating the latest regulations and understanding of health and safety practices and integrating theory with practice throughout, Conservation of Easel Paintings, Second Edition will continue to be an indispensable reference for practicing conservators. It will also be an essential resource for students taking conservation courses around the world.

A collaboration aiming to improve knowledge and procedures for conservation of Panel Paintings has been in force since several years between OPD (Opificio delle Pietre Dure, Florence) and the Research Group on Wood Technology of DAGRI (University of Florence). In such framework a research is here presented, which for the first time has led to dimensioning rationally (i.e. by means of objective criteria based on Conservation, on Engineering and on Wood Science principles) the stiffness of the crossbeams of an original Panel Painting. Crossbeams typically have a double function: a) to control the deformation of the panel painting when it undergoes climate changes and b) to stiffen the panel painting for handling purposes. If too stiff or too yielding, crossbeams might damage the wooden support or the paint layers; until today the choice of their stiffness was entrusted to the expert but subjective judgment of the Restorers alone, who therefore have been calling for a confrontation with Wood and Engineering Scientists in order to develop more objective criteria. To satisfy this request the research here mentioned has been carried out, in close collaboration between the Restorers of OPD and the Wood Scientists of DAGRI, to develop a specific protocol allowing for the rational dimensioning of the stiffness of crossbeams. This protocol is based on an engineering modular approach, and for the first time it has been applied on an original artwork, the Adorazione del bambino e committente attributed to Cesare da Sesto (1514-1520). One of the modules of such protocol is to assess the stiffness of both the crossbeams and the wooden support and, in such framework, this paper presents the non-invasive mechanical tests that were designed and implemented to check in-situ various mechanical parameters (including the axial holding capacity) of the original nail connections between the crossbeams and the wooden support. Such knowledge might in general be helpful especially during the diagnostic phase, to understand the internal forces still acting into the wood structure, and possibly their influences on the degradation of the paint layers in relation to the behaviour of the wooden support.

When wooden supports of panel paintings have been severely altered or damaged and the original crossbeams are missing, new crossbeams or other types of auxiliary supports can be connected to the panel’s back-face in order to achieve desired effects including panel strengthening and control of deformations. In order to make such connection, the Restorers of Opificio delle Pietre Dure use small wooden blocks, each glued on the back face of the panel, and holding freely the head of a screw connected (often by means of springs) to the auxiliary support; the English term ‘buttons’ has been proposed for such blocks. This research examines in depth how the shape (conical or cylindrical) and dimensions (diameter in the 20-30 mm range, and thickness in the 3-6 mm range) of the buttons, all made from oak wood, influence their stiffness and load-carrying capacity. Each button was glued onto a dummy beech board by means of epoxy structural resin; a 3 mm diameter steel screw was inserted in each button’s hole prior to gluing, so that its head remained ‘trapped’ between the button’s cavity and the board. A short-term mechanical test was performed with a universal testing machine by axially pulling out the screw from the button. Load and displacement were recorded, and the load–displacement curves were analysed. The results showed that within the tested range: a) the ultimate load-carrying capacity of the buttons is only influenced by the residual thickness above the screw head, b) nor the shape nor the external diameter of the buttons have any influence on their mechanical properties, c) the stiffness (slope of the straight part of the load-displacement curve) of the connection depends only on the embedding of the screw head into the wood (i.e. mainly on the wood density).