Optical Imaging Applications for the Study of Cultural Heritage Artifacts

The chapter entitled Optical Imaging applications for the Study of Cultural Heritage Artefacts proposes to make an overview on the contribution that different imaging techniques (from the traditional, more often used, stereomicroscopy and optical microscopy to more innovative tools, such as confocal microscopy and 3D digital microscopy) can bring to the field of cultural heritage conservation and restoration. The paper will present and discuss the surface investigation of cultural heritage artefacts and cross-section examination of samples taken from them, using different optical imaging tools (mainly visible – by reflection, polarized and/or transmitted light observation - and fluorescence imaging). Following a short introduction on the main techniques of optical imaging used today and their specific methods/approaches for Science and Forensic applications, advantages and limitations of these techniques will be discussed in relationship with the specific requirements of the conservation field. A special attention will be paid to the methods of sample preparation such as cross-section and thin section and their use with other tools using imaging and microscopic observation (staining tests, immunologic and histological techniques). The imaging applications on Cultural Heritage artefacts will be discussed according the different steps of investigation in conservation science field: the study and characterization of art materials and techniques, the assessment of the conservation state (studying degradation and deterioration mechanisms and processes), the authentication of works of art, the monitoring of restoration interventions in situ and in laboratory and compatibility studies etc. A particular attention will be paid to characterization of supports (wood, textile fibres, plaster, ceramic, metal and glass), paint and coating materials (such as pigments, metal leafs, binders and varnishes). Case studies on important artefacts (paintings, sculptures, textiles with metallic threads, ceramics and plasters, glass negatives) from the European heritage will illustrate these applications and the usefulness of optical imaging for practical conservation and for authentication purposes. Besides these, other case-studies from ongoing laboratory researches on different topics (such as cleaning with enzymes and application of different cleaning methods on plaster) will contribute to illustrate the usefulness of the optical imaging in the current scientific research in conservation field.