In situ Accelerated Light Ageing with Portable Microfade Spectrometry

Project Partners: Tate, English Heritage, Fondation Beyeler, Science Museum, Victoria & Albert Museum, Royal Horticultural Museum

Sponsors: NTU, Tate (2006-2009), Science Museum (2011), English Heritage (2012), Fondation Beyeler (2012), AHRC (2013)

Explanation

Microfading was first developed by Paul Whitmore in 1991 for efficiently detecting extremely light-sensitive materials on objects in situ to determine the appropriate exhibition lighting conditions. By focusing an intense beam of light to a tiny sub-mm sized spot and simultaneously monitoring the colour change over time, the fading rate of the material can be measured without producing noticeable damage. The increased intensity of light allows rapid determination of light-fastness of materials. We have been developing automated portable and easy to assemble microfade spectrometers that is capable of high precision fading measurements. The latest version (2013) has improved stability by a factor of four compared with the 2010/2011 version.

Application of Microfade Spectrometry

• A study of how well different paints follow the reciprocity principle. If the light induced degradation of a material follows the reciprocity principle, then the extent of degradation only depend the total energy and independent of the light intensity. However, this does not always appear to be the case for pigments.
• Investigating the light sensitivity of textiles at Audley End House (English Heritage).
• Investigating the light sensitivity of various paint on Henri Matisse's Acanthes, a major work in the artist's series of large format papiers decoupes (Fondation Beyeler).
• Investigating the light sensitivity of Chinese export watercolour paintings from the Royal Horticultural Society and the Victoria & Albert Museum.
• Light sensitivity of wall paintings in a Silk Road cave temple site – Mogao caves.

Conference presentations

• Invited talk on 'Latest Instrumental Developments on Portable Microfading Spectrometry', Anoxia and Microfading: The Impact on Collection Care, Tate Modern, 12-13 September 2011
• Presentation on Development of portable microfading spectrometers for measurement of light sensitivity of materials, at the ICOM-CC 16th Triennial Conference, Lisbon, 19 - 23 September 2011
• Haida Liang, Andrei Lucian, Chi Shing Cheung, Bomin Su, Systematic non-invasive optical investigation of wall paintings at a UNESCO World Heritage Site, SPIE O3A, Munich, May 2013
• Presentation by Haida Liang on Systematic non-invasive optical investigation of wall paintings at a UNESCO world heritage site, EU COST meeting, Mainz, Germany March 2013
• Invited talk on “Contributions of astronomy to the study of art conservation and archaeology" at the workshop From Antikythera to the Square Kilometre Array: Lessons from the Ancients, 11 - 16 June 2012

• Liang H., Lange R., Lucian A., Hyndes P., Townsend J., Hackney S., Development of portable microfading spectrometers for measurement of light sensitivity of materials, in ICOM-CC 16th Triennial Conference Preprints, Lisbon, 19-23 September 2011, ed. J. Bridgland, 1612_882, Lisbon: Critério - Artes Gráficas, Lda. ISBN 978-989-97522-0-7
• Lerwill A., Townsend J., Liang H., Thomas, J. and Hackney, S., Portable Microfading Spectrometer for Versatile Light Fastness Testing, E-Preservation Science, (2008) Vol. 5, 17-28.
• Lerwill A., Townsend J., Liang H., Thomas J., Hackney S., A versatile microfadometer for lightfastness testing and pigment identification, in O3A: Optics for Arts, Architecture, and Archaeology, Proc. SPIE(2007), Vol. 6618, 66181G