3D imaging uncovers 19th century painting techniques
The Swiss Institute for Art Research (SIK-ISEA) is using 3D imaging software to help researchers understand 19th century painting techniques.
Among other issues this study is looking at the paintings' grounds, which are mixtures of binding media, fillers, and pigments applied to a suitable support as a preparation for painting. In particular it has set a focus on the possible connection between the porosity of grounds, their absorption characteristics, the overall appearance, and the stability of the paintings.
Recent research at the art technology department of SIK-ISEA in collaboration with Tomcat beamline at PSI Villigen has shown that X-ray tomography is a uniquely powerful method to study the internal structure in intact ground samples. The current research challenge is twofold and lies in, firstly estimating precisely the distribution of voids and pores and the connectivity of the porosity network at a micrometer scale, and secondly visualising the impregnation and transport of moisture through the ground.
The 3D tomographic data sets are being studied using Avizo software from the Visualization Sciences Group (VSG), a provider of high-performance 3D visualisation software and graphics toolkits. Avizo enables visualisation and quantitative analysis of the data sets by providing appropriate filtering algorithms and advanced segmentation tools.
In attempting to characterise the degree of porosity or the capability of a ground to incorporate moisture, the study addresses a pressing conservation question: The presence of an absorbing layer within the painting build-up has important consequences for the painting's stability. Issues of water-accelerated reactivity and moisture gradient-assisted material mobility within complex paint systems have been recognised, but never studied. The characterisation of the structure of absorbent ground layers is a first step towards the study of the mobility of materials between layers.