Use of Raman Microspectroscopy in Various Art Mediums and Discoveries
What is Raman microspectroscopy?
Raman microspectroscopy is one implementation of chemical studies to determine authenticity, degradation effects, and identification of raw materials and their processing (Kelloway and Birmingham). It is the study of light and the manner in which light is scattered, producing a spectra that can reveal much about an artwork and its content beneath the surface.
Leonardo da Vinci Painting
Art conservation is a heavy task involving high stakes – in the art market, millions of dollars are at risk, and there is also the moral responsibility of preserving cultural heritage. Raman microspectroscopy is extremely helpful in discovering forgeries, or in the case of the recently discovered Leonardo painting, establishing authenticity. Salvador Mundi was originally thought to have just been a copy created by Boltraffio, a studio artist working under Leonardo, but chemical analysis revealed it to be an original (Reyburn). The surface layers, consisting of varnish and overpaint, had concealed the identifying characteristics of Leonardo paintings. Raman microspectroscopy was used in conjunction with infrared spectroscopy to reveal the layers beneath the surface, detecting and identifying inorganic pigments and their spectra, as well as the exact order in which paint was applied to the surface (Tague). Such a discovery was extremely noteworthy in contemporary times, when all Leonardo paintings were thought to have been known, catalogued, and in possession of museums and collectors. It quickly sold for $80 million, a high price to be expected because a situation involving the “discovery of a Leonardo” may never happen again.
Pottery and Ceramics
As mentioned before, Raman microspectroscopy can be implemented in the study of degradation and identification of materials from a chemistry standpoint. Such analyses often reveal more than just chemical composition when studying ancient pottery – it serves as an indication of the culture these materials are from as well as its ceramic traditions and how such pottery techniques developed. Raman microspectroscopy can be used to identify glaze inclusions and their origins for future reference (Kelloway and Birmingham). In the case of the 19th century Australian pottery, Raman spectra from inclusions identified in the glazes allowed scientists to determine the glaze ingredients used as well as the potting techniques and practices from which the ceramics were made.
Copper Alloy Artifacts
Raman microspectroscopy was used in conjunction with other art conservation methods to study the blue corrosion products found on copper alloy artifacts from the Asian Art Museum of San Francisco and the Detroit Institute of the Arts (Trentleman). Raman spectra of the blue corrosion product was analyzed, and results indicated the presence of formate and acetate groups, which helped enforce a theory that scientists had. The corrosion product may have been caused by chemical reactions between copper alloys and acid vapors from the storage or display case materials, a discovery that could lead to complications in the way art is stored and shown to the public.
Example of spectra taken from a painting – each line represents a different color present in the piece examined.
Works Cited
KELLOWAY, SARAH, and JUDY BIRMINGHAM. “Profiling Nineteenth-Century Australian Potteries: Approaches to Provenancing Ceramics and Identifying Potting Practices.” Australasian Historical Archaeology, vol. 28, 2010, pp. 35–42. www.jstor.org/stable/41433074.
Leona, Marco et al. “Identification of the Pre-Columbian Pigment Maya Blue on Works of Art by Noninvasive UV-Vis and Raman Spectroscopic Techniques.” Journal of the American Institute for Conservation, vol. 43, no. 1, 2004, pp. 39–54. www.jstor.org/stable/3179850.
Reyburn, Scott. “Putting a Price on Leonardo.” The New York Times. The New York Times, 09 Mar. 2014. Web. 26 Nov. 2016.
Tague, Thomas J., Jr. “Utilization of Infrared and Raman Micro-Spectroscopy for the Chemical Analysis of Art.” Forensic Magazine. N.p., 12 Feb. 2013. Web. 26 Nov. 2016.
Trentelman, K. et al. “The Characterization of a New Pale Blue Corrosion Product Found on Copper Alloy Artifacts.” Studies in Conservation, vol. 47, no. 4, 2002, pp. 217–227. www.jstor.org/stable/1506782.
