A main concern for the documentation of artworks is how to reveal the information that stems from the internal paint layers of artworks (stratigraphy). This information is up to now mainly acquired through analytical spectroscopic methods which require a micro-sampling operation. Most of the times, the objects under study are extremely valuable and therefore must not be subjected to any intervention. This fact constitutes the micro sampling a prohibitive procedure. So there is a demand for the development of Non Destructive Testing (NDT) techniques for the acquisition of cross section (depth profile) information from the paint layers of artworks. The current state-of-the-art developments on the Ultraviolet/ Visible/near Infrared and mid Infrared (UV/VIS/nIR/mIR) spectroscopy in diffuse-reflectance mode and on acoustic microscopy, support the decision to use the combination of these two methods in order to non-destructively identify the stratigraphy in specific Regions Of Interest (ROIs) of artworks. The general conception of the overall system is shown in Fig. 1. Using acoustic microscopy, we can obtain the number of layers in the stratigraphy. Using UV/VIS/nIR and mIR spectroscopy in diffuse-reflectance mode, the identification of materials that exist in each paint-layer can be achieved. Since a wide spectral area is used for the spectra acquisition, the information provided from several sub-spectral areas are eventually be exploited separately. The UV/VIS area provides with “strong” information about the upper layer, while the IR area for the under-layers. The identification of the materials is made using Neural Networks techniques.
Mr. Georgios KARAGIANNIS
Mr. Georgios KARAGIANNIS is Electrical Engineer graduated from Aristotle University of Thessaloniki, Department of Electrical Engineering. He is a Engineer of the ORMYLIA Art Diagnosis Centre. His research field is related to NDT Techniques applied to artwork diagnosis and documentation, Image and Signal Processing, as well as Database Development and knowledge management and representation. He is the author of about 25 publications and communications to national and international conferences. He holds (shares) also three patents (two nationals and one international). He is also project manager in several R&D and industrial projects funded by the European Commission and the Industry.