Friday, June 1 • 3:30pm - 4:00pm
35. (Research and Technical Studies) Optimizing Paint Cross-Section Preparation for Modern and Contemporary Art: A Case Study

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Big Egg (1968) by Ed Clark is a large oval-shaped abstract painting on canvas, created while the artist was working in France. The painting is from the National Museum of African American History and Culture (NMAAHC) collection and underwent technical study and conservation at the Museum Conservation Institute (MCI). Clark is known for his technique of painting with the canvas on the floor, pouring and splashing many thin layers of paint and pushing them around with a large broom. Much of the paint surface has a matte and chalky appearance. Big Egg was originally thought to be acrylic, but preliminary analysis showed the underlying paint layers to be water sensitive and the pigments to be bound in polyvinylacrylate (PVAc) with a possible ethylene co-polymer. Currently, the painting is on view at the Visual Art Gallery at NMAAHC. This study is a continuation of research conducted in 2015-2016 on un-embedded paint samples from Big Egg with ATR-FTIR and Hirox microscopy. In this study, a paint cross-section embedding and polishing technique was developed to further the binder and pigment analysis of each paint layer with FTIR chemical mapping and SEM-EDX. This research is part of broader investigations by the authors with the goal to optimize paint sample preparation for modern and contemporary art. The paint cross-section methodology is as follows: 1) embed the paint sample in Bio-Plastic® 2) mount the embedded sample on double-sided silicon tape onto a glass slide 3) place the paint layers parallel to the glass slide 4) ensure strata of paint is fully on view when the sample is released from the mold 5) use metal tube as mold, ¾” in diameter cut to ¾” height 6) coat the interior of the mold with silicon grease 7) a negligible amount of resin exists between the paint sample and silicone tape resulting in minimal polishing 8) dry polish with MicroMesh 8) use Hirox reflective bright field to confirm paint sample surface topography. The analysis of the paint cross-sections starts from the least invasive technique, ending with the more invasive method—from Hirox microscope examination to FTIR mapping (measured in reflectance mode) to SEM-EDX. Using the methodology listed above, a paint cross- from Big Egg was analyzed and 13 layers of paint were observed. The thickness, inorganic elements, and binder of each stratum was examined by FTIR mapping and SEM-EDX. Water-sensitive PVAc paint in Big Egg was confirmed by ATR-FTIR on non-embedded paint and FTIR mapping of the embedded paint cross-section. This result supports the treatment selection of water-based consolidant, water-based inpainting material, and the choice of Beva film as a lining adhesive. Fully polished paint cross-sections ready for analysis can be prepared within a day. The application has been extended to include egg tempera paint, photographs, and polychrome. This cross-section preparation expands the instrumental analysis capability from one paint sample, maximizing the information gathered. Future work includes more comparative experiments with ion milling systems to improve the paint surface quality and further organic material analysis with FTIR-mapping.

avatar for Jia-sun Tsang

Jia-sun Tsang

Senior Paintings Conservator, Museum Conservation Institute
Jia-sun Tsang is senior paintings conservator at the MCI, where she conserves paintings for Smithsonian museums. She holds an M.Sc. from the Winterthur/University of Delaware Program in Art Conservation and an M.Sc. in chemistry from Bowling Green State University, OH. Since 2007... Read More →

avatar for Stephanie Barnes

Stephanie Barnes

Conservator of Paintings, Barnes
Stephanie Barnes is a graduate of the Queen's University Master in Art Conservation program where she specialized in the conservation of paintings. She also holds a B.Sc. in Chemistry from Mount Allison University and an M.Sc. in Chemistry from Laval University. Stephanie recently... Read More →
avatar for Elle D Friedberg

Elle D Friedberg

Pre-Program Intern, Worcester Art Museum
Elle Friedberg is the Pre-Program Intern at the Worcester Art Museum in Worcester, MA. Previously, she has held internships at the Smithsonian Museum Conservation Institute, National Gallery of Art, and Smithsonian National Museum of American History in the greater DC area. Friedberg... Read More →
avatar for Thomas Lam

Thomas Lam

conservation scientist, Smithsonian Conservation Institute
Thomas Lam has a Ph.D. in Ceramics from Alfred University. After his PhD, Thomas completed a postdoc at the National Institute of Standards and Technology (NIST). Thomas is a Physical Scientist at the Smithsonian Museum Conservation Institute (MCI), where he applies his knowledge... Read More →

Friday June 1, 2018 3:30pm - 4:00pm
Texas Ballroom (Foyer outside Ballrooms - Poster Session) Marriott Marquis Houston

Attendees (36)