The detection of incamottatura through radiography: investigations on real cases and panel painting mock-ups

Abstract

The historical techniques of panel painting manufacturing involve the preparation of boards to be used as painting support. The high affinity of wood for water can cause dimensional variations, deformations, and internal tensions. The application of a canvas over the boards, besides the choice and treatment of wood, is useful to minimize and guarantee the stability and preservation of the painting over time. The detection of the fabric is ensured with different imaging techniques, such as macro photography and radiography. The latter is mainly used to obtain information about the characteristics of the wood, the number of boards, the assembly system, and for the evaluation of the conservation state. The main advantage is the non-invasiveness of the analysis, which is a fast, simple, and widespread method. The limitations are related to different factors, such as the capacity of the materials to absorb the radiation. Despite canvas has a low radiopacity, in several cases it was possible its identification in the radiograph. This is important to investigate the technique of the artists. In our laboratory, we analyzed different panel paintings and while in some cases the fabric is easily detectable, in others it's not visible. Different variables can limit the observation of the canvas. This study is aimed at the comprehension of how acquisition parameters and painting characteristics can affect the detection of incamottatura through radiography.