ABSTRACT
OCT provides an art conservator with information about the structure of varnish, glaze and paint layers in a non-contact and non-invasive way (Targowski et al. 2004, Liang et al. 2005,Targowski et al. 2006). In this low-coherence interferometric technique a narrow beam of light is sent to the object. The light scattered and/or back reflected on its structural elements carries information about their locations within the object. The application of the technique is thus limited to imaging of transparent and semitransparent layers. So far, it is well suited for varnish layers imaging, especially in old pictures where the layer is thick enough to clearly distinguish boundaries even with moderate resolution OCT systems. Examinations of modern varnish layers often require a higher axial resolution.
