Testing the light sensitivity of artworks using a portable microfade spectrometer



Museums struggle to balance the need to protect artworks that are light-sensitive with the desire to give visitors the best experience possible. Microfading was developed in the 1990s for efficiently detecting extremely light-sensitive materials on objects in situ, to help better determine the appropriate exhibition lighting conditions. By focusing an intense beam of light on a tiny sub-millimetre-sized spot and simultaneously monitoring the colour change over time, the fading rate of the material can be measured without producing noticeable damage.

Addressing the Challenge

However, the first generation of systems were bulky, manually operated, and not easily portable. We have been developing automated, portable and easy-to-assemble microfade spectrometers that are capable of high-precision fading measurements. It is said that using the results of microfading for accelerated light aging tests can save museums over £1 million a year.


Professor Haida Liang is Head of the Imaging & Sensing for Archaeology, Art History & Conservation (ISAAC) research group.

Teaching duties include: Module Leader for Year One Concepts of: Astronomy and Cosmology, Year Three Cosmology: Theory and Observation; teaching contributions to Year Two Stars & Galaxies, MSc Medical Imaging and MSc Materials and Security Imaging.

Areas of research include the development of advanced optical imaging and spectroscopic instruments for non-invasive and non-destructive examination, applications of physics (particularly imaging and optics) to art conservation and archaeology, as well as astrophysics.

Making a Difference

The Tate Gallery funded a PhD project at NTU to develop a microfadometer to measure the light sensitivity of watercolour paintings and help design the optimum exhibition conditions. A follow-on project with Higher Education Innovation Funding (HEIF) allowed development of a more robust portable system, which has been used for projects in the Science Museum, English Heritage, Fondation Beyler in Switzerland, the Royal Horticultural Society, the Victoria and Albert Museum and Dunhuang Academy in China.

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