In 1977, Northwestern University chemist Richard Van Duyne developed a powerful analytical technique called surface enhancing Raman spectroscopy (SERS). It is able to identify the chemical make-up of a particular dye by using laser light and nanoparticles of metals to interact with the dye's molecules. The vibration frequencies of the chemical bonds are measured and are characteristic of the elements present in the sample. Some major advantages of SERS are its ability to analyze extremely small samples of organic dyes and how it is non-destructive when it comes to analyzing organic dyes, particularly red ones. Conventional Raman spectroscopy can easily damage red dyes due to its light and fluorescence. And what sets this technique apart from others is its ability to tell you the elements present in the artwork. According to Van Duyne, unlocking the secrets of dye and pigment analysis will help conservators determine forgery, authenticity, and better restoration methods in the future.
This technique has led Van Duyne to investigate famous art pieces at the Art Institute of Chicago and learn more about the materials used in each of them. One of his recent projects focused on Winslow Homer's painting, "For to be a Farmer's Boy" painted in 1887. Some of the red and yellow pigments have faded in the sky of the painting, leaving it almost colorless. Van Duyne and his colleagues used SERS and other analytical techniques, such as X-ray fluorescence spectrometry, to determine what the original colors of the sky were. They discovered that the white skies in the painting were originally painted with unstable red and orange dyes that have almost completely faded. From this discovery, conservators at the Art Institute plan to create a digital image of what the painting looked like originally to give viewers an idea of the artist's intentions.
1 comment:
The visiting conservation scientist who will speak at the Carlos Museum will be discussing this collaboration.
I had friends in grad school who did research with Professor Van Duyne, but none of them work on art analysis. They were mostly developing instrumentation.
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