•Notícia

Works of art are unique and valuable objects. In technical appraisals and authentications of specific pieces, it is vital to identify the materials used in their production, and this can be done using a range of unambiguous non-invasive analytical techniques introduced in recent years. “When I heard about the applications of Raman spectroscopy in the art world, I was struck by the possibility of relating two disciplines that apparently have little in common”, explains Mireia Castanys, who obtained her PhD in telecommunications engineering at the School of Telecommunications Engineering of Barcelona.

As she suggests, the two disciplines are in fact highly complementary: “We use fiber-optics, lasers, signal processing and communications, but to develop applications for the art world, which is a much less technical field than most engineers are accustomed to working in”.

Raman spectroscopy is a photonic molecular analysis technique that, when applied to art, can be used to determine the pigments in a painting without damaging the materials, since no sample is required and the surface of the painting is not touched. The technique is based on the Raman effect, which occurs when a beam of monochromatic light scatters upon contact with a material, producing highly specific frequencies that identify the composition of the material in question. Mireia Castanys explains that, “The spectrum obtained is like a fingerprint that provides the information needed to characterize and identify a material with absolute certainty”.

Pigments are usually identified by visual comparison of an experimental spectrum obtained from a painting with a series of references stored in a database, which tell us whether we are looking at a Prussian blue or a Naples yellow. However, this procedure can be slow and laborious, and the results are often subjective. The thesis written by Mireia Castanys, based on research carried out at the Raman Spectroscopy Laboratory, aims to solve these problems.


To prevent the influence of subjective criteria and to increase the speed and precision of the process, the thesis proposes an automatic system for identifying Raman spectra.

Castanys explains that the instrument “makes an objective suggestion, for example, giving you the percentage correspondence between the spectrum and the pigment lead-tin yellow. However, once this information has been obtained, the expert will still need to take a final decision”.