Preliminary study of the formation of cracking and flaking phenomena on oil paintings on copper through the artificial aging of two miniature paintings

Abstract

Fluctuations in environmental conditions appear to affect the conservation of paintings on copper and in this article we report the results of tests carried out using a simple experimental setup to confirm previous studies to show how temperature and RH (relative humidity) fluctuations influence the development of degradation phenomena affecting these paintings. The experiment was conducted on real miniature paintings and the results underline the impact that variations in RH can have on the preservation of oil paintings on copper. The contribution here aims to provide more data to enrich the available information on this topic and broaden the reflection on the risk factors for the conservation of this type of painting. The study also proposes a simple experimental setup with self-made climate chambers which can be useful to artificially test samples or materials for other studies in the conservation field.

Riassunto

“Studio preliminare dei fenomeni di formazione di crettature e sollevamenti sui dipinti ad olio su rame attraverso l’invecchiamento artificiale di due miniature”

Le fluttuazioni delle condizioni ambientali sembrano influenzare la conservazione dei dipinti su rame e in questo articolo riportiamo i risultati dei test eseguiti utilizzando un semplice assetto sperimentale per confermare studi precedenti ed evidenziare come le variazioni di temperatura e l’umidità relativa (UR) influenzino lo sviluppo di fenomeni di degrado che interessano questi dipinti. L’esperimento è stato condotto su due vere miniature e i risultati sottolineano l’impatto che le variazioni di umidità relativa possono avere sulla conservazione di dipinti ad olio su rame. Il presente contributo si propone di fornire ulteriori dati per arricchire le informazioni disponibili su questo argomento e ampliare la riflessione sui fattori di rischio per la conservazione di questa tipologia di dipinti. Lo studio propone inoltre un semplice assetto sperimentale con l’utilizzo di camere climatiche autoprodotte che può essere utile per testare artificialmente campioni o materiali per altri studi nel campo della conservazione e il restauro.

Résumé

« Etude préliminaire sur la formation de phénomènes de fissuration et d'écaillage sur des peintures à l'huile sur cuivre grâce au vieillissement artificiel de deux peintures miniatures »

Les fluctuations des conditions environnementales semblent affecter la conservation des peintures sur cuivre et dans cet article nous rapportons les résultats de tests effectués à l'aide d'un dispositif expérimental simple pour confirmer des études antérieures montrant comment les fluctuations de température et d'humidité relative influencent le développement des phénomènes de dégradation affectant ces peintures. L'expérience a été menée sur de véritables peintures miniatures et les résultats soulignent l'impact que les variations d'humidité relative peuvent avoir sur la conservation des peintures à l'huile sur cuivre. La contribution vise ici à fournir plus de données pour enrichir les informations disponibles sur ce sujet et élargir la réflexion sur les facteurs de risques pour la conservation de ce type de peinture. L'étude propose également une installation expérimentale simple avec des chambres climatiques fabriquées manuellement qui peuvent être utiles pour tester artificiellement des échantillons ou des matériaux pour d'autres études dans le domaine de la conservation.

Zusammenfassung

„Vorläufige Studie zur Entstehung von Riss- und Abplatzerscheinungen bei Ölgemälden auf Kupfer durch künstliche Alterung zweier Miniaturgemälden“

Schwankungen der Umweltbedingungen scheinen die Konservierung von Gemälden auf Kupfer zu beeinflussen. In diesem Artikel berichten wir über die Ergebnisse von Tests, die mit einem einfachen Versuchsaufbau durchgeführt wurden, um frühere Studien zu bestätigen und zu zeigen, wie Temperatur- und Luftfeuchtigkeitsschwankungen (relative Luftfeuchtigkeit) die Entwicklung von Degradationserscheinungen bei diesen Gemälden beeinflussen. Das Experiment wurde an echten Miniaturgemälden durchgeführt, und die Ergebnisse unterstreichen die Auswirkungen, die Schwankungen der relativen Luftfeuchtigkeit auf die Konservierung von Ölgemälden auf Kupfer haben können. Der vorliegende Beitrag zielt darauf ab, mehr Daten zur Verfügung zu stellen, um die verfügbaren Informationen zu diesem Thema zu erweitern und die Überlegungen zu den Risikofaktoren für die Erhaltung dieser Art von Gemälden zu vertiefen. In der Studie wird auch ein einfacher Versuchsaufbau mit selbstgebauten Klimakammern vorgeschlagen, der nützlich sein kann, um Proben oder Materialien für andere Studien im Bereich der Konservierung künstlich zu testen.

Resumen

“Estudio preliminar de la formación de fenómenos de agrietamiento y descamación en pinturas al óleo sobre cobre mediante el envejecimiento artificial de dos pinturas en miniatura”

Las fluctuaciones de las condiciones ambientales parecen afectar a la conservación de las pinturas sobre cobre. En este artículo se presentan los resultados de las pruebas realizadas con un sencillo montaje experimental, para confirmar estudios anteriores y mostrar cómo las fluctuaciones de temperatura y HR (humedad relativa) influyen en el desarrollo de los fenómenos de degradación que afectan a estas pinturas. El experimento se llevó a cabo con pinturas en miniatura reales y los resultados subrayan el impacto que las variaciones de la HR pueden tener en la conservación de las pinturas al óleo sobre cobre. Esta contribución pretende aportar más datos para enriquecer la información disponible sobre este tema y ampliar la reflexión sobre los factores de riesgo para la conservación de este tipo de pinturas. El estudio también propone un montaje experimental sencillo con cámaras climáticas de fabricación propia que puede ser útil para ensayar artificialmente muestras o materiales para otros estudios en el campo de la conservación.

摘要

“关于形成铜版油画裂纹和剥落现象的初步研究——基于两幅微型油画人工老化实验”

环境条件的波动似乎会影响铜板油画的保存。本文报告的测试结果证实了先前的研究，通过简易实验装置，说明了温度和相对湿度（RH）的波动如何影响油画产生降解现象。实验是在真实的微型画作上进行的。实验结果强调了相对湿度的变化对铜板油画保存的影响。本研究旨在提供更多数据，以丰富该主题的现有信息，并加深人们对此类绘画保存风险因素的思考。该研究还提出了一种自制气候室的简易实验装置，可用于人工测试其他保护研究的样本或材料。

Keywords:

• degradation of oil paintings
• paintings on copper
• preventive conservation
• self-made climatic chambers
• RH
• temperature

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19455224.2023.2299458.

Acknowledgements

The authors would like to thank Paolo Plebani, curator of the Accademica Carrara di Bergamo, Angelo Loda from the Soprintendenza Archeologia Belle Arti e Paesaggio per le province di Bergamo e Brescia, and Marianna Ferrero from the Centro Conservazione e Restauro Venaria Reale and Tommaso Poli from the Università degli Studi di Torino. Our gratitude goes also to the conservator Isabel Horovitz for her extreme cordiality, her interest in the project, and her availability and advice.

Notes

1 Laura Fuster Lopez and Marion F. Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties of Oil Paint Film in Copper Paintings and the Effects of Environment in their Structural Behaviour’, in Paintings on Copper and other Metal Plates. Production, Degradation and Conservation Issues, ed. Laura Fuster Lopez et al. (València: Politècnica de València, 2017), 95–102.

2 Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

3 Isabel Horovitz, ‘The Consolidation of Paintings on Copper Supports’, in ICOM Committee for Conservation 11th Triennial Meeting Edinburgh 1–6 September 1996 (Edinburgh: James & James Ltd, 1996), 276–81, https://www.icom-cc-publications-online.org/2955/The-Consolidation-of-Paintings-on-Copper-Supports (accessed 24 November 2023).

4 See, for example, Isabel Horovitz, Copper as Canvas: Two Centuries of Masterpiece Paintings on Copper, 1675–1775, Exhibition catalogue, Phoenix Art Museum (Oxford: Oxford University Press, 1999); Isobel Horovitz, ‘Paintings on Copper: A Brief Overview of their Conception, Creation and Conservation’, in Fuster Lopez et al., Paintings on Copper and other Metal Plates, 17–26; Lydia-Chara Pavlopoulou, ‘Chemical, Physical and Mechanical Decay Processes in Oil Painted Copper Objects’, in Fuster Lopez et al., Paintings on Copper and other Metal Plates, 83–94.

5 Isabelle Leegenhoek-Wade, ‘Les tableaux peints sur cuivre. Origine, constitution, conservation’ (unpublished Masters Thesis, Institut Francaise de Restauration des oeuvres d’art, 1983); Horovitz, ‘Paintings on Copper: A Brief Overview’; Isobel Horovitz, ‘To Those Who Like Their Pictures in Pristine Condition … : Techniques of European Paintings on Copper’, Picture Restorer 22 (2002): 16–9; David A. Scott, Copper and Bronze in Art: Corrosion, Colorants, Conservation (Los Angeles: Getty Conservation Institute, 2002); Pavlopoulou, ‘Chemical, Physical and Mechanical Decay Processes in Oil Painted Copper Objects’; Nico Broers, ‘Preparation Techniques and their Impact on the Conservation of Copper Paintings’, in Fuster Lopez et al., Paintings on Copper and other Metal Plates, 71–82; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

6 Horovitz, Copper as Canvas; Horovitz, ‘To Those Who Like their Pictures in Pristine Condition’; Horovitz, ‘Paintings on Copper: A Brief Overview’; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

7 Isabel Horovitz, ‘Paintings on Copper Supports: Techniques Deterioration and Conservation’, The Conservator 10 (1986): 44–8; Horovitz, Copper as Canvas; Horovitz, ‘Paintings on Copper: A Brief Overview’; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

8 Alan Bush, ‘Copper as a Support: The Chemical Deterioration of Copper Panels’, Picture Restorer 3 (1993): 16–7; Daniella Serrano Serrano, Consolidamento e stuccature dei dipinti su rame: Il restauro della Madonna con Bambino e angeli di provenienza sconosciuta (Firenze: Tesi di Laurea, Opificio delle Pietre Dure, Scuola di alta formazione e studio, 2017); Horovitz, ‘Paintings on Copper Supports’.

9 Horovitz, ‘Paintings on Copper Supports’; M. Letizia Amadori, Fabiano Ferrucci, and M. Giulia Terenzi, Dipinti su rame: storia, tecnica, fenomeni di degrado, diagnostica; indicazioni per la conservazione e il restauro (Padua: Il prato casa editrice, 2006).

10 M.F. Mecklenburg, ‘Structural Response to Relative Humidity. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 1’ (2007), https://www.si.edu/sisearch/search-all-else?edan_q=conservation%2Bmecklenburg; M.F. Mecklenburg, ‘Structural Response to Temperature. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 2’ (2007), https://www.si.edu/sisearch/search-allelse?edan_q=conservation%2Bmecklenburg (both accessed 24 November 2023); Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

11 Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

12 Mecklenburg, ‘Structural Response to Temperature. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 2’.

13 Horovitz, Copper as Canvas.

14 Mecklenburg, ‘Structural Response to Relative Humidity. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 1’; Mecklenburg, ‘Structural Response to Temperature. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 2’; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

15 Mecklenburg, ‘Structural Response to Relative Humidity. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 1’.

16 Mecklenburg, ‘Structural Response to Relative Humidity. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 1’; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

17 Mecklenburg, ‘Structural Response to Relative Humidity. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 1’; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

18 W.K. Asbeck and Maurice Van Loo, ‘Critical Pigment Volume Relationships’, Industrial & Engineering Chemistry 41, no. 7 (1949): 1470–5.

19 Dodd S. Carr and B.J. Harris, ‘Solutions for Maintaining Constant Relative Humidity’, Industrial & Engineering Chemistry 41, no. 9 (1949): 2014–5; Lewis Greenspan, ‘Humidity Fixed Points of Binary Saturated Aqueous Solutions’, Journal of Research of the National Bureau of Standards—A. Physics and Chemistry 81A, no. 1 (1977): 89–96.

20 Robert L. Opila, Charles J. Weschler, and Rudolf Schubert, ‘Acidic Vapors above Saturated Salt Solutions Commonly used for Control of Humidity’, Transactions on Components. Hybrids and Manufacturing Technology 12, no. 1 (1989): 115–20.

21 Mecklenburg, ‘Structural Response to Relative Humidity. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 1’; Mecklenburg, ‘Structural Response to Temperature. Determining the Acceptable Ranges of Relative Humidity and Temperature in Museums and Galleries, Part 2’; Fuster Lopez and Mecklenburg, ‘A Look into some Factors Influencing the Film Forming Properties’.

22 Horovitz, Copper as Canvas; Isobel Horovitz, ‘Copper as Support for Easel Paintings’, in Conservation of Easel Paintings, ed. Joyce Hill Stoner and Rebecca Rushfield (London: Routledge, 2012), 99–106.

23 David Erhardt and Marion Mecklenburg, ‘Relative Humidity Re-examined’, in Preventive Conservation in Museums, ed. Chris Caple (London: Routledge, 2011), 340–54.

24 Norma UNI 10829 1999, Beni di interesse storico e artistico, condizioni ambientali di conservazione. Misurazione ed analisi. Le Norme UNI sono acquistabili sul sito www.uni.com.

25 Decreto ministeriale 10 Maggio 2001, Ministero per i beni e le attività culturali. Atto di indirizzo sui criteri tecnico-scientifici e sugli standard di funzionamento e sviluppo dei musei.

26 Norma UNI 10829; Decreto ministeriale 10 Maggio 2001.

27 D. Erhardt and M. Mecklenburg, ‘Relative Humidity Re-examined’, in C. Caple, Preventive Conservation in Museums, 340–54.

28 Helen McKay, Care of Paintings on Ivory, Metal and Glass—CCI Notes 10/14 (Government of Canada: Canadian Conservation Institute, 2015), https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/care-paintings-ivory-metal-glass.html (accessed 6 December 2023).

29 Lydia-Chara Pavlopoulou and David Watkinson, ‘The Degradation of Oil Painted Copper Surfaces’, Reviews in Conservation 7 (2006): 55–65; Pavlopoulou, ‘Chemical, Physical and Mechanical Decay Processes in Oil Painted Copper Objects’.

Additional information

Notes on contributors

Laura Ruggieri

Laura Ruggieri is a conservator specialising in easel paintings and contemporary art. She received her MA in Conservation and Restoration Cultural Heritage from the University of Turin.

Tiziana Cavaleri

Tiziana Cavaleri is a Conservation Scientist at Centro per la Conservazione ed il Restauro dei Beni Culturali La Venaria Reale. She holds a Masters Degree in Science and Technology for Cultural Heritage (2009) and a second Masters Degree in Material Science from the University of Turin (2017).

Eliano Diana

Eliano Diana is associate professor in General and Inorganic Chemistry at the University of Turin. He received his MA in Chemistry from the University of Turin.

Maria Beatrice Failla

Maria Beatrice Failla is associate professor of Museology, History of Art Criticism and Conservation at the University of Turin. She received her MA in Arts from the University of Turin.

Bernadette Ventura

Bernadette Ventura is a conservator at Centro Conservazione restauro La venaria Reale. She is a restorer of paintings on wood and textiles, and received her MA in Cultural Heritage Restorer from Opificio delle Pietre Dure, Florence.