Optical coherence tomography for art conservation & archaeology

Optical coherence tomography (OCT) is a fast scanning Michelson interferometer originally designed for in vivo imaging of the eye. In 2004, our group along with two other groups first reported the application of OCT to art conservation and archaeology. Since that time we have been conducting a project to investigate systematically the potential of OCT as a new tool for non-invasive examinations of a wide range of museum objects and to design an OCT optimised for in situ use in museums. Here we present the latest results from this ongoing project, which include the determination of the optimum spectral windows for OCT imaging of paintings and painted objects executed using traditional techniques, and non-invasive imaging of the subsurface stratigraphy of painted layers at multiple wavelengths. OCT imaging in assisting spectral pigment identification and in measuring refractive indices of paint will also be presented to illustrate the potential of the technique.