Specialty Session At AIC's 50th Annual Meeting

Contributor Mary Slater
Sunday, May 15, 2:00-2:30 PM PST
Los Angeles, CA
In-person & online

Evaluating the efficacy of cyclododecane in cross-sectional architectural paint analysis.

Senior Conservator Katey Corda and Conservator Brooke Russell will review the implementation of the cyclododecane preparation method on architectural paint samples that are highly sensitive to resin infiltration.

Abstract:
Embedding finish samples in clear resin is the most commonly accepted method of performing cross-section analysis for the identification of pigments and media in the conservation field. Polyester, epoxy, or acrylic resins are typically used. The resin holds the delicate paint layers intact, allowing the grinding and polishing process needed for cross-section examination while preserving the sequential stratigraphy. The resin additionally allows for enhanced visibility under microscopy.
This standard method of cross-section preparation comes at a cost. The resin often penetrates and embeds within the sample, particularly in more porous samples such as water soluble or under-bound (paint with a higher pigment to media ratio) paint samples, altering not only the optical appearance and color characterization of the layers, but also impacting the ability to perform many types of chemical and molecular analysis accurately. In short: the resin ruins the analytic potential of the sample.

A novel approach to inhibiting the infiltration of the resin into paint samples was published in the Journal of Analytical and Bioanalytical Chemistry in June, 2008. The article, titled Stratigraphic analysis of organic materials in wall painting using micro-FTIR attenuated total reflectance and a novel sample preparation technique (Martin de Fonjaudran, Pique, Nevin and Cather) posits that by coating the paint sample in melted cyclododecane, the cyclododecane will prevent the resin from infiltrating porous paint materials during the embedding process. Upon curing and exposure of the sample face through polishing or cutting, the cyclododecane will sublimate, resulting in a resin-surrounded, but not infiltrated, paint sample.

The aim of this article is to review the implementation of the cyclododecane preparation method on architectural paint samples that are highly sensitive to resin infiltration– namely, distemper paints – and determine if this is a viable alternative to direct resin binding. It will discuss pertinent nuances for success in the preparatory process. In addition, it will compare the process to the standard method and discuss the benefits of the cyclododecane method as a low-cost, low-tech, readily accessible option.

Special thank you to co-authors Senior Conservator Mary Slater and Catherine Matsen of the Winterthur Museum, Garden, and Library for their input and support.