OCT system to examine priceless paintings

A team of researchers from Nottingham Trent University have received more than £600,000 of funding to develop a new Optical Coherence Tomography (OCT) system that they hope will become a tool used by art galleries around the world.

The funding was received from the Science and Heritage Programme of the Arts and Humanities Research Council (AHRC) and the EPSRC.

Since 2004, Dr Haida Liang from the university’s School of Science and Technology has led research into the application of Optical Coherence Tomography (OCT) for the non-invasive examination of paintings.

Originally developed as a medical imaging tool, OCT uses infrared light to penetrate biological tissue that scatters the light back. This scattered light is then detected by the device, allowing it to measure the distance it has travelled and therefore produce a three-dimensional image of the inner structures of the tissue.

However, since realising the potential for OCT to be applied in the examination of works of art, Dr Liang and her team have spent the past six years pioneering various applications for work in art history, archaeology and art conservation.

In the case of paintings, the depth and distribution of paint and varnish layers, and even the artist’s preparatory drawings, can be made visible, all of which can help art conservators and curators to better understand the historical significance and what is required to preserve priceless artefacts.

Dr Liang and her team now hope that a variety of improvements can be made to the effectiveness of current OCT systems, all of which will be of benefit to its users.

Using the grant from the AHRC and EPSRC, they will now turn their attention to developing an OCT system that uses a broader band and longer wavelength of light to improve the resolution and depth of penetration that can be achieved.

These improvements will allow OCT users to collect a level of detailed information that is currently only possible by physically removing samples from artefacts and examining them with a microscope. It will also help to establish a reputation for OCT as a tool for non-invasive imaging in the heritage field, highlighting its benefits as an early warning tool for detecting deterioration and problems for conservation.

In addition, an ongoing partnership with the National Gallery and a recently formed collaboration with English Heritage will allow the researchers to apply OCT to the examination of paintings, enamels, glass and ceramics.