2010 IR Workshop

Catherine Patterson

[Click here for the talk abstract]

Biography

Catherine Patterson received a Ph.D. in Chemistry (Physical/Analytical) from Northwestern University before accepting a Postdoctoral Fellowship in Conservation Science at the Getty Conservation Institute (GCI). Dr. Patterson then joined the GCI as an Assistant Scientist in the Collections Research Laboratory, where she is responsible for the scientific study of works of art in the collection of the J. Paul Getty Museum.

Dr. Patterson's research is focused on the application of a diverse range of analytical techniques to the study of cultural heritage objects and materials, with an emphasis on non-invasive and minimally invasive technologies. Her recently published work describes novel approaches to the identification of organic red colorants and the analysis and geological provenancing of lapis lazuli pigments. She is also currently involved in collaborative research investigating 14th century Florentine workshop practice, assessed through technical analysis of the works of the panel painter/manuscript illuminator Pacino di Bonaguida.

Abstract

Use of FTIR Spectroscopy and FTIR Imaging in Cultural Heritage Research

The ability to remove samples from priceless works of art and cultural heritage artifacts is typically very limited, both in terms of sample numbers and their size. The identification of organic materials in such samples often presents a significant analytical challenge since common methods of analysis, such as HPLC or GC-MS, generally require the consumption of a large amount of material. FTIR spectroscopy, which either can be carried out non-invasively in situ, or, more commonly, on micro-samples taken from targeted areas of a work of art, has therefore long played an important role in the analysis of cultural heritage objects.(1)

When applied to cultural heritage samples, FTIR spectroscopy is used either to provide specific material identifications or as a general characterization method to direct further analysis by additional techniques. FTIR spectroscopic analysis has proven particularly important in the analysis of binding media (e.g. oil, acrylic, egg) in paints, adhesives, plastics, resins, and both synthetic and natural organic colorants.  

FTIR microscopy on micro-samples, either in their original form or mounted as cross-sections, provides a means of increasing the amount of information that can be gleaned from each sample removed from a work of art. FTIR imaging provides a more complete measure of the most significant molecular components of a micro-sample than can be developed from individual spot scans. Furthermore, by coupling molecular identification to spatial distribution, cultural heritage scientists may, for example, be able to gauge the extent of degradation processes, evaluate the efficacy of conservation treatments by measuring the distribution of organic components across a cross-section, or elucidate an artists' working technique through an evaluation of individual paint layers. 

In paintings, a layer of interest may only be on the order of only a few microns thick. Therefore, the high spatial resolution (on the order of 1-5 ┬Ám) provided by a synchrotron-based FTIR microscope is well suited to the study of cultural heritage samples,(2) not only facilitating the examination of smaller samples, but allowing the examination of features at an unprecedented level of detail.

(1) Derrick, M. R.; Landry, J. M.; Stulik, D. C. Methods in scientific examination of works of art : infrared microspectroscopy; Getty Conservation Institute Los Angeles, 1991.

(2) Salvado, N.; Buti, S.; Tobin, M. J.; Pantos, E.; Prag, A.; Pradell, T. Anal. Chem. 2005, 77, 3444-3451.