An Exploration of Consolidants for Ancient Egyptian Limestone

ABSTRACT

The Penn Museum has many monumental architectural elements of the Palace Complex of Merenptah, a 19th Dynasty Egyptian pharaoh. The palace was excavated in Memphis by Clarence Fisher and elements of it, including columns, doorways, and windows, were brought to Philadelphia and installed in the Museum in 1926. The limestone architectural pieces exhibit various condition issues including powdering, flaking, and cracking. In preparation for reinstallation in the Museum’s renovated Egyptian galleries, methods and materials for strengthening and stabilizing the stone were investigated. First, the stone was characterized using thin-section petrographic analysis. After a literature search, the following consolidation materials were selected for initial testing: Conservare, CaLoSil E5, CaLoSil E25, CaLoSil E50, CaLoSil IP5, CaLoSil IP25, diammonium phosphate (DAP), and M-3P bacterial nurturing solution. Test areas were evaluated for reduced powdering, improved strength, and minimal visual change (if any). CaLoSil E5 and M-3P were then further tested to better compare their performance with each other. Paraloid B-72 was also considered for this project and selected for stabilizing areas with structural damages like breaks and cleavage. This article outlines the steps taken and results of testing. It also addresses the treatment choices made for these architectural elements, and the rationale for them.

RÉSUMÉ

Le Penn Museum possède plusieurs éléments architecturaux monumentaux du Palais de Mérenptah, un pharaon de la 19e dynastie d'Égypte Ancienne. Le palais fut fouillé à Memphis par Clarence Fisher et certains éléments, dont des colonnes, des portails et des cadres de fenêtre furent importés à Philadelphie et installés au Museum en 1926. Les éléments architecturaux en calcaire démontrent certains signes de détérioration, par exemple : de la pulvérulence, de la délamination et de la fissuration. En vue de la réinstallation de ces éléments dans les galeries égyptiennes rénovées du Museum, certaines méthodes et matériaux pour renforcer et stabiliser la pierre ont été investigués. Premièrement, la pierre fut caractérisée à l'aide d'examen pétrographique sur tranche mince. Après une recension de la littérature, les agents de consolidation suivants ont été sélectionnés pour les premiers essais : Conservare, CaLoSil E5, CaloSil E25, CaLoSil E50, CaLoSil IP5, CaLoSil IP25, le phosphate diammonique (PDA), ainsi qu'une solution d'élevage bactérien M-3P. Les aires d'examen furent évaluées avec comme critères, la réduction de pulvérulence, le renforcement de la pierre, et les changements visuels minimes éventuels. Le CaLoSil E5 et la solution M-3P furent ensuite réexaminés pour mieux comparer leur performance. Le Paraloid B-72 fut aussi envisagé pour ce projet et sélectionné pour stabiliser les régions avec des dommages structuraux tels des cassures ou des clivages. Les étapes et les résultats des examens sont présentés dans cet article. Les traitements de restauration choisis pour ces éléments architecturaux et le raisonnement derrière ces choix y sont aussi décrits. Traduit par Anne-Marie Guerin.

RESUMO

O Penn Museum tem muitos elementos arquitetônicos monumentais do Complexo do Palácio de Merenptah, um faraó da 19a. Dinastia Egípcia. O palácio foi escavado em Memphis por Clarence Fisher e seus elementos, como colunas, portais e janelas, foram trazidos para a Filadélfia e instalados no Museu em 1926. As peças arquitetônicas de calcário apresentam várias questões de conservação como pulverização, delaminação e rachaduras. Nos preparativos para a reinstalação das galerias egípcias renovadas, foram pesquisados métodos e materiais para fortalecer e estabilizar a pedra. Primeiro, a pedra foi caracterizada por meio de análise petrográfica de lâmina delgada. Após uma pesquisa bibliográfica, os seguintes materiais consolidantes foram selecionados para testes iniciais: Conservare, CaLoSil E5, CaLoSil E25, CaLoSil E50, CaLoSil IP5, CaLoSil IP25, fosfato diamônico (DAP) e M-3P solução nutritiva bacteriana. As áreas de testes foram avaliadas quanto à redução de pó, melhora na resistência e alteração visual mínima (se houver). CaLoSil E5 e M-3P foram então testados para comparar melhor os desempenhos de ambos entre si. O Paraloid B-72 também foi considerado para este projeto e selecionado para estabilizar áreas com danos estruturais como quebras e clivagem. Este artigo descreve as etapas executadas e os resultados dos testes. Também aborda as escolhas de tratamento feitas para estes elementos arquitetônicos e suas justificativas. Traduzido por Sandra Baruki; revisado por Beatriz Haspo.

RESUMEN

El Museo Penn cuenta con numerosos elementos arquitectónicos monumentales del Complejo del Palacio de Merenptah, un faraón egipcio de la Dinastía XIX. El palacio fue excavado en Menfis por Clarence Fisher y algunos de sus elementos, como columnas, entradas y ventanas, fueron traídos a Filadelfia e instalados en el Museo en 1926. Las piezas arquitectónicas de piedra caliza presentan diversos problemas de conservación, como pulverulencia, descamación y agrietamiento. En preparación para su reinstalación en las galerías egipcias renovadas del Museo, se investigaron métodos y materiales para fortalecer y estabilizar la piedra. En primer lugar, se caracterizó la piedra mediante análisis petrográfico de secciones delgadas. Tras una búsqueda bibliográfica, se seleccionaron los siguientes materiales de consolidación para pruebas iniciales: Conservare, CaLoSil E5, CaLoSil E25, CaLoSil E50, CaLoSil IP5, CaLoSil IP25, fosfato de diamonio (DAP) y solución bacteriana nutriente M-3P. Se evaluaron áreas de prueba en función de la reducción de pulverulencia, mejora de la resistencia y cambios visuales mínimos (si los hubiera). Luego, CaLoSil E5 y M-3P se probaron más a fondo para comparar su comportamiento entre sí. Paraloid B-72 también se consideró para este proyecto y se eligió para estabilizar áreas con daños estructurales, como fracturas y desprendimientos. Este artículo describe los pasos realizados y los resultados de las pruebas. También aborda las decisiones de tratamiento tomadas para estos elementos arquitectónicos y la lógica detrás de ellas. Traducción y revisión: Vera de la Cruz y Ramón Sánchez; revisión final: Amparo Rueda e Irene Delaveris.

KEYWORDS:

• Merenptah
• limestone
• consolidation
• CaLoSil
• nanolimes
• bacterial consolidant

Acknowledgements

The authors are deeply grateful for all our colleagues at the Penn Museum, the University of Pennsylvania, the Winterthur Museum, the University of Delaware, and at various other locations for sharing their expertise with us. At the Penn Museum, specific thanks go to Lynn Grant, Tessa de Alarcon, Dr. Kevin Cahail, Conservation Department, Egyptian Section. At the University of Pennsylvania, specific thanks go to Dr. Marie-Claude Boileau, Courtney Magill, Paul Verhelst, CAAM Students. At the Winterthur Museum, specific thanks go to Dr. Rosie Grayburn, Catherine Matsen, Dr. Judy Rudolph. Additional thanks to Pepe Cabello, Hiroko Kariya, Carolyn Riccardelli, Carrie Roberts, Anna Serotta, Dr. George Wheeler, Skyler Jenkins, and those who offered comments and/or feedback following our initial presentation of this study during the American Institute for Conservation Annual Meeting in 2020.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Nina Owczarek

Nina Owczarek (she/her) is Assistant Professor at the University of Delaware in the Art Conservation Department, primarily teaching in the undergraduate program. Prior to joining UD faculty, she was Associate Conservator at the University of Pennsylvania Museum of Archaeology and Anthropology (Penn Museum), where she worked for nine years. She is a graduate of the Conservation Center, Institute of Fine Arts, New York University. Owczarek served as Secretary/Treasurer for the Object Specialty Group (2016–2020) and was on the Education and Training Committee (member 2014–2020, Vice Chair 2018, Chair 2019). She is a Fellow member of AIC. Address: 305 Old College Hall, 18 E Main St., Newark, DE 19711, USA. E-mail address: [email protected].

Anna O’Neill

Anna O’Neill Alexander (she/her) is the owner of A. O’Neill Conservator, LLC, providing treatments and consultations for institutions and individuals. She was an objects conservator working with the Egyptian Collection at the Penn Museum from 2017 to 2020. She received her MSc in Conservation Practice at Cardiff University in 2014. Her interests include ethnographic and ethical conservation. Address: 2141 N. 62nd Street, Wauwatosa, WI 53213, USA. Email: [email protected].

Molly Gleeson

Molly Gleeson (she/her), is the Schwartz Egyptian Collections Conservator at the Penn Museum, located at the University of Pennsylvania in Philadelphia, PA. Molly regularly works in the museum’s visible conservation lab where she treats artifacts in full public view, interacts with museum visitors daily, and blogs about the work in the lab and is a lead project conservator for the Ancient Egypt and Nubia Galleries project. Molly completed her MA at the UCLA/Getty Master’s Program in the Conservation of Archaeological and Ethnographic Materials and her undergraduate degree in art conservation from the University of Delaware. Molly is a Professional Associate member of AIC and is the AIC Board Director for Professional Education. She works closely with AIC's Emerging Conservation Professionals Network (ECPN), the Education and Training Committee, and the Equity and Inclusion Committee. Address: 1354 Marlborough St., Philadelphia, PA 19125, USA. Email: [email protected].

Jessica Betz Abel

Jessica Betz Abel (she/her) is a Project Conservator at the Penn Museum in Philadelphia. She was previously the Andrew W. Mellon Fellow at the Michael C. Carlos Museum at Emory University specializing in objects conservation. She has worked as a conservator at the Museum of Modern Art, the Smithsonian Museum Conservation Institute, and the Hirshhorn Museum and Sculpture Garden. Jessica earned her M.S. from Columbia University in architectural conservation. Additionally, she has participated in archeological excavations at Gordion, Turkey and Samothrace, Greece. Email: [email protected].

Julia Commander

Julia Commander (she/her) is the Alice and Herbert Sachs Conservator of Egyptian Collections at the Penn Museum. She joined the Ancient Egypt and Nubia Galleries reinstallation project in 2019, focusing on monumental stone architecture. Julia earned her M.S. from the Winterthur/University of Delaware Program in Art Conservation in 2017 and completed post-graduate training at the J. Paul Getty Museum and the Metropolitan Museum of Art, as well as field work at the Gordion Archaeological Project. Address: 2206 E Gordon St., Philadelphia, PA 19125, USA. Email: [email protected].