Portable Spectroscopy System used at UCL for the study of Dali canvases

Analytik report on the use of the ASD LabSpec portable NIR spectroscopy system in the Centre for Sustainable Heritage at UCL. They use the system for the scientific research of historic objects as part of a project with a prestigious group of European institutions, the work of which has been published by the Royal Society of Chemistry in Analytical Methods.

The group has been collaborating on the development of a new, non-destructive method to diagnose a painting canvas from the back, and without disturbing a single fibre, to see if it can withstand the stress of handling and travel. This project was carried out in a unique collaboration between researchers and conservators at the University of Barcelona's Department of Conservation, University of Ljubljana, University of London's Birkbeck College and The British Library.

Using the method scientists examined 12 paintings by the surrealist painter Salvador Dalí. While all 12 were shown to be in a good condition and can continue to be enjoyed safely, there was evidence of the early canvases approaching the threshold for safe travel.

Using fibre optics to shine invisible near infrared light on the canvas, the scientists obtained information about the 'health' of the painting from the reflection of the light. Since canvas is the carrier of paint, any tears or other mechanical degradation could lead to loss of the image if the canvas is too brittle. "While distressed paint layers can be evaluated visually from the front, there has been no method available so far to evaluate the fragility of canvas without actually cutting off a piece of it, which is certainly unacceptable" explained Irene Civil, Head of the Conservation Department of the Gala-Salvador Dalí Foundation from Figueres, Spain.

Dr Strlic has been working with NIR for several years, first publishing a protocol for testing historic paper in Analytical Chemistry in 2007. He describes the reasons for using NIR in his work. "Regardless of the fact that FTIR and Raman spectrometers are often used for the purpose, and portable solutions are also becoming available, they have not yet proven to be as versatile as NIR. The flexibility offered by our LabSpec system, including the possibility of use of a reflectance probe accessory and fibre optics, enables us to examine samples of different geometries and sizes."