E-RIHS UK partners often design and build bespoke machines and scientific instruments for use in galleries, museums and heritage sites. Based at Nottingham Trent University, ISAAC has been innovating scientific instruments and applying its expertise to solving conservation, art history and archaeology problems across the globe. The laboratory is unique in developing advanced non-invasive imaging systems that are not only novel in optical and remote sensing instrumentation but also novel in applications to the museum and cultural heritage sector.
Among the technique innovation offered by the laboratory, ISAAC has been working on the improvements in Optical Coherence Tomography (OCT). OCT involves fast, non-invasive, non-contact, microscopic imaging of subsurface cross-section and 3D tomography. This imaging method, originally designed for biomedical applications such as in vivo examination of the eye, facilitates non-invasive 3D imaging of subsurface microstructure. As the original OCTs have been optimised for medical use, ISAAC has been researching ways of improving its capabilities for use in the heritage sector.
During instrumentation innovation projects, funded by the Leverhulme Trust and the Arts and Humanities Science and Heritage Programme, ISAAC built and tested prototype OCT systems to generate ‘virtual’ cross-sections of paintings and heritage objects. To this end, the laboratory has worked with heritage partners such as the National Gallery and English Heritage to increase the depth resolution and the probing depth of the instruments. The improved OCT technique enabled in-depth images of artist’s preliminary sketches and underdrawings. It also facilitated a detailed examination of the painting surfaces, and the distribution of the remains of old varnishes. The innovation has reduced the need for sampling and enable the subsurface microstructure to be imaged on intact objects where sampling was not possible. It has also encouraged more frequent and thorough examination of the whole object for early warning of deterioration. For Carolyn Allen from the Leverhulme Trust, developing an instrument that “‘sees through’ layers of paint and varnish, revealing previously hidden levels of detail about paintings and other historical artefacts”.
Bespoke OCT is a powerful imaging tool for heritage institutions. It helps to inform conservation strategy and create long-term savings in the cost of conservation through monitoring degree of deterioration. It also enables the scientists to explore new problems in conservation and art history that the next generation OCT can help to solve. According to Dr Liang, as ISAAC has established Optical Coherence Tomography as a new field of heritage science, the laboratory has been deploying the technique for new user communities:
“We now have a much more enthusiastic response from the conservation community and even private conservators contact us wanting to have access to this type of instrument”.
The ISAAC team has used their bespoke equipment on a variety of projects such as the influential studies of manufacturing techniques of the Limoges enamel and ancient Egyptian Faience at the British Museum or wall paintings at the Tower of London.
Currently, ISAAC is equipped with a range of in-house developed OCT systems that could be used not only in research on underdrawings, but also studies involving the detection of delamination of internal layers and monitoring of varnish removal and glass deterioration. Recently, the team has extended the application of OCT to a variety of industrial and biomedical problems. The laboratory and research group is continuously collaborating with other E-RIHS partners in research and innovation in multiple heritage science applications.
The Imaging & Sensing for Archaeology, Art History & Conservation laboratory (ISAAC) has been applying cutting-edge science to cultural heritage challenges for over twelve years. The laboratory focuses on applications of scientific techniques and works in collaboration with conservation scientists, conservators, archaeologists, archaeological scientists and art historians and curators. Previous collaborations included partners in the heritage sector in the UK, Europe, China, and USA.
The laboratory uses a wide range of instruments, including:
- Spectral imaging systems
- Fibre optic reflectance spectrometer (FORS)
- Portable X-ray Fluorescence (XRF) spectrometer
- Compact Fourier Transform Infrared (FTIR) spectrometer
- Raman Spectrometer
- Microfade spectrometry
- Optical Coherence Tomography (OCT) systems
- Nuclear magnetic resonance (NMR) Mouse