Issues and challenges in the restoration and presentation of a double-sided artwork

The Petit Palais museum has been working for many years in close collaboration with the CICRP and is offering the opportunity to the public to discover the scientific studies and restorations that the works have undergone, in the format of case study exhibits: the Case Studies of the Petit Palais. These case studies have been as successful in satisfying public curiosity and demand for precise and current information on the works as the request made by the Museums of France Heritage Department to refocus on the permanent collections.

The second piece of the series, ‘Popular piety in Italy in the 15th century. The banner of Saint Blaise by Niccolò da Foligno’, is dedicated to an important banner painted by Niccolò da Foligno. This piece, which has significantly enriched the collections of the Petit Palais museum, is part of the Campana collection given on permanent loan by the Louvre Museum in 1976. Probably commissioned by the brotherhood of Santa Maria del Vescovado of Assisi from the most accomplished Umbrian painter of the 15th century, this very large two-sided processional banner is the only example of this type of devotional object in France’s collections. It was awaiting restoration before being presented to the public.

 

Contributors

• Dominique Vingtain, director of the Petit Palais museum: Brief history of a very long restoration [histoire d’une très longue restauration]

• Monique Pomey, restorer (reserve): Restoration of the banner at the CICRP [La restauration de la bannière au CICRP]

• Sarah Boularand, CICRP chemist: Results of the last chemical analyses [Les résultats des dernières analyses chimiques]

• Marie Mayot, assistant director of the Petit Palais museum: Presentation of a two-sided piece and its restoration to the public [La présentation d’une œuvre biface et la restitution au public]


Duration: 2002–2009

CICRP: Philippe Bromblet, Jean-Marc Vallet

Partnerships(s): Bureau of Geological and Mining Research (BRGM), Historic Monuments Research Laboratory (LRMH) and Olivier Rolland, restorer

This research programme, launched in 2002 on Bourges Cathedral, has subsequently benefited from financing for a duration of two years (2004–2006) under the National Research Project on the Conservation and Knowledge of Heritage (PNRCC) on the isotopic tracing of sulphate sources leading to the weathering of stone monuments.

The objectives were the following:

  • to specify the origins of the soluble sulphates responsible for the degradation of the stones
  • to identify and quantify the contributions of different sources identified, whether natural and internal to the stone (e.g. pyrite) or external (marine sprays), unintentional anthropogenic (urban atmospheric pollution) or intentional (plaster, Roman cement).

Different sites of investigation were selected for their environmental characteristics and their type of stone: the cathedrals of Bourges, Chartres and Marseille, and the châteaux of Chenonceau and of Versailles (garden).

The new aspect of the methodology concerns the use of a multi-isotopic ‘toolbox’ including the measurement of the isotopic signature of sulphur and oxygen constituting these solid sulphates (‘SO4’) and of the boron present in traces in the form of borates (‘BO3’). The isotopic analyses have been carried out on altered stone, mortar, plaster and black crust samples taken in different conditions from the different sites. The isotopic analyses have thus made it possible to shed light on the respective contributions of the sulphates originating from atmospheric pollution (classed under ‘black crust’) and from the materials (plaster, mortars). The use of isotopic dosages of sulphur and oxygen constitute a promising tool in determining the origins of sulphates associated with the degradation of stone.

Publications:

  • Kloppmann W., Rolland O. and Bromblet Ph., ‘Isotope study (S,O) of sulphate neoformations involved in the degradation of stones on Bourges Cathedral (France): internal versus external salt sources’, Proceedings of the 10th International Congress on Deterioration and Conservation of Stone, Stockholm, Sweden, 2004, p. 595–602.
  • Vallet J.-M., Gosselin C., Bromblet Ph., Rolland O., Vergès-Belmin V. and Kloppmann W., ‘Origin of salts in stone monument degradation using sulphur and oxygen isotopes: first results of the Bourges Cathedral (France)’, Journal of Geochemical Exploration, vol 88, 1–3, Jan–march 2006, GES-7, 7th International Symposium on the Geochemistry of the Earth’s Surface, 23–27 August 2005, Aix en Provence, p. 358–362.
  • Kloppmann W., Vergès-Belmin V., Gosselin C., Rolland O., Bromblet Ph., Vallet J.-M. and Dotsika E., ‘Isotope (sulphur, oxygen, boron) tracing of internal or external origin of sulphates involved in the degradation of French monuments (BOS project)’, Proc. of the 7th European Conference ‘Sauveur’, Safeguarded Cultural Heritage, Understanding & Viability for the Enlarged Europe, 31st may – 3rd June 2006, Prague, Czech Republic, 2007, vol. 1, p.437–440.
  • Kloppmann W., Vergès-Belmin V., Rolland O., Bromblet Ph., Vallet J.-M. and Gosselin C., ‘Néoformation de sulfates comme facteur de dégradation des pierres des monuments : détermination par traçage isotopique (B, O, S) des sources internes et externes du soufre’, Proceedings of the symposium Science des matériaux du patrimoine culturel, 6 and 7 December 2007, Paris, France, Techné, Special Issue, 2008, p.114–119.
  • Kloppmann W., Bromblet Ph., Vallet J.-M., Vergès-Belmin V., Rolland O., Guerrot C. and Gosselin C., ‘Building materials as intrinsic sources of sulphate: A hidden face of salt weathering of historical monuments investigated through multi-isotope tracing (B, O, S)’, (2011) Sci Total Environ, 409, pp. 1658–1669.

Duration: 2008–2009

CICRP: Alain Colombini

Partnership(s): Museums of France Research and Restoration Centre Centre (C2RMF)

A research programme on the identification and behaviour of PVC materials was undertaken in liaison with the Museums of France Research and Restoration Centre (C2RMF), primarily from analyses carried out on pure PVC resins, current consumer products and works of art, particularly inflatable structures.

Publication:

BALCAR, N. and COLOMBINI, A., ‘Approche multi-analyses pour l’étude du PVC : cas de structures gonflables’, presented to Art d’aujourd’hui, patrimoine de demain, S.F.I.I.C., Paris, June 2009.


Duration: 2010–2011

CICRP director: Alain Colombini

Partnership(s): Research Centre for the Conservation of Collections (CRCC); ARC-Nucléart; Laboratory of Molecular and Macromolecular Photochemistry of Clermont-Ferrand; Museums of France Research and Restoration Centre (C2RMF), in the context of a Regional Natural Park of Corsica (PNRC)

This project focuses on celluloid, a material widely used during the 20th century but which has become almost obsolete due to the risks associated with its usage, as well as its stability. The project has yielded proposals for conservation and treatment measures drawing on studies carried out on heritage works.


Duration: 2010–2011

CICRP: Alain Colombini

Partnership(s): Research Centre for the Conservation of Collections (CRCC), Laboratory of Molecular and Macromolecular Photochemistry (LPMM); Museums of France Research and Restoration Centre (C2RMF); Gwenola Corbin, conservator-restorer, National Centre of Plastic Arts (CNAP) grant

Under the restoration research allowance granted to Gwenola Corbin by the National Centre of Plastic Arts (CNAP), the CICRP has provided scientific assistance to this research project. The topics addressed have focused on identification techniques for rubbers present in museum collections, their degradation processes and their consolidation.

Publication:

Corbin G. (2007), ‘Recherche sur la conservation et la restauration de Foot Soldier (Godzilla) de Kenji Yanobe. Complétée d’une étude sur les mousses polyuréthannes souples’, Ecole Supérieure d’Art d’Avignon, report p. 241.


Duration: 2006–2010

CICRP programme steering: Katia Baslé (director), Fabien Fohrer

Partnership(s): CRPAA, University of Bordeaux 3

The use of ethylene oxide is becoming increasingly limited due to its toxicity and the fact that it will be banned for the treatment of contaminated cultural property, without any other method to replace it. C2N2 (ethane dinitrile or cyanogen) is a less toxic gas that might be a viable alternative. The CICRP has thus undertaken a research programme to verify the effectiveness of C2N2 on strains of moulds most frequently encountered on cellulosic material by studying three parameters: gas concentration, relative humidity level and duration of treatment.


Duration: 2003–2010

CICRP: Katia Baslé, Nicolas Bouillon, Fabien Fohrer, Odile Guillon

Partnership(s): Institute of Archaeomaterials Research, UMR CNRS 5060, IRAMAT-CRPAA; University of Bordeaux 3; Agro Techmo Hygiene, University of Perpignan

Following serious conservation problems tied to environmental conditions, particularly the deterioration of organic material due to infestation by Stegobium paniceum, especially for easel paintings in the Mediterranean region, the CICRP has established starting from 2006 an interdisciplinary programme around four principal topics:

  • The assessment of infestations and their development in painted works by a protocol of standardised photography based on the automatic counting of flight (or exit) holes by image processing.
  • The identification of the most attractive formulas and ingredients using infestation tests on laboratory-made samples of relined paintings.
  • The analysis of glue-pastes by GC/MS so as to correlate their attractiveness according to their chemical composition.
  • The establishment of a StegoSIG geographic information system

Publications:

  • Fohrer F., Basle K. and Daniel F., ‘Compréhension et analyse des phénomènes d’infestation et de réinfestation par le Stegobium paniceum des peintures de chevalet rentoilées à la colle de pâte’, Support Tracé, 2006, 6: 78–83.
  • Bouillon N., Fohrer F. and Bonnafoux B., ‘Study of pest infestation of glue-paste lined easel paintings: characterization of traditional glue-paste recipes and their relevant Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry’, ICOM Committee for Conservation, 15th Triennial Meeting in Delhi, India Preprints, September 2008.
  • Baslé K., Bouillon N., Fohrer F., Guillon O. and May R., ‘Pour une approche raisonnée des problématiques d’infestation en milieu patrimonial : le cas du Stegobium paniceum‘, Techné 2009, no. 29.
  • Baslé, K. and May, R.,: ‘StegoSIG : un système d’information géographique pour connaitre et prévenir les risques d’infestation, appliqué au milieu patrimonial’, METANIR Project under the European Programme Noé (2006–2007), 2007, pp. 71–84.

Duration: 2007–2010

CICRP programme steering: Philippe Bromblet (director) and Jean-Marc Vallet

Partnership(s): Center for Interdisciplinary Nanoscience of Marseille (CINaM), Paul Cézanne Aix University – Marseille III

The research efforts on the role of soluble salts in the alteration of materials have been carried out primarily in the context of the doctorate of Julie Désarnaud, student co-supervised by the CINaM and the CICRP. This doctorate, entitled ‘Alteration process of stones by cristallisation of soluble salts’, has been financed by a PACA regional grant.

This research has consisted in renewing the experiments carried out since 1920 (Taber, Correns etc.) that are at the root of the concept of cristallisation pressure. An experimental device was developed to measure the displacement induced by potential growth of the constrained faces of a KCl crystal submerged in a saturated solution in a controlled environment of T and HR and subjected to a known initial theoretical constraint on its upper face. The dimensions and weights of crystals are monitored before and after the experiment. The development of the height of the crystal is continuously monitored during the entire duration of the experiment by a displacement sensor. The experiment is carried out under different conditions (contact or near-contact of the mechanical constraint and the crystal, different rates of solution saturation etc.). In every case, the height of the crystal decreases progressively through the dissolution of the constrained summital and basal faces. The constrained faces have a higher solubility than the non-constrained faces and dissolve under mechanical constraint in every scenario, in accordance with Riecke’s principle as well as the general laws of crystalline growth. These experiments call into question the notion of crystallisation pressure as referred to in alteration phenomena of stone relating to soluble salts.

Publications:

  • Workshop CRYSPOM 1 organised by the École Nationale des Ponts et Chaussées in Paris in 2008, communication and publication of the summary ‘Crystal growth under mechanical constraint: new experimental results using KCl‘, J. Désarnaud, p. 1.
  • Workshop CRYSPOM 2 organised by ETH Zurich in 2010 at Brienz, Switzerland, communication and publication of the summary, ‘Growth and dissolution of a loaded KCl crystal: Impact and limit of the supersaturation rate‘, Desarnaud J., Baronnet A., Bromblet P., Vallet J.-M. and Grauby O., p. 1.
  • Désarnaud J., Baronnet A., Bromblet P., Grauby O. and Vallet J.-M. (2008), ‘Crystal growth under mechanical constraint: new experimental results using KCl’, Proceedings from the International Conference on Salt Weathering of Buildings and Stone Sculptures, 22–24/10/2008, Copenhagen, Denmark, Technical University of Denmark, 103–113.
  • Désarnaud J., ‘Mécanisme de croissance et de dissolution de cristaux de KCl sous charge, apport dans la connaissance des altérations des pierres par les sels’, thesis of Paul Cézanne Aix University – Marseille III, 2009, p. 197.
  • Désarnaud J., Baronnet A., Bromblet P., Grauby O. and Vallet J.-M., ‘Growth and dissolution of crystals under load: new experimental results on KCl‘, submitted to Crystal Growth & Design.

Duration: 2007–2011

CICRP: Philippe Bromblet

Partnership(s): Regional Archaeology Department and Regional Directorate of Cultural Affairs (DRAC), Provence Alpes Côte d’Azur; Vaucluse Archeology Department; Laboratory of Medieval Mediterranean Archaeology; Historic Monuments Research Laboratory (LRMH)

The purpose of this project is to study the use of Caromb stone in construction efforts from antiquity to the 19th century. This consists primarily in demonstrating how and why this stone became widespread over a large territory (Carpentras, Avignon, Aix) and was used as a substitute for other stone materials (Orgon stone), eventually itself giving way to other regional stones from the 19th century onwards (Crillon stone). This research, carried out in collaboration with historians, archaeologists and geologists, aims to compare samples with the provenance indicated in texts describing approximately 15 structures, and to study the principal characteristics and weathering behaviour of Caromb stone.

Publication:

Bernardi P., Bromblet P., Barret R., Vallet J.-M., Mignon J.-M. and Lise Leroux, ‘La production de pierres à Caromb (Vaucluse) : premiers résultats d’une enquête sur une industrie rurale au Moyen Âge’ (2008), Proceedings of the international symposium Pierres du Patrimoine Européen, Economie de la pierre de l’Antiquité à la fin des temps modernes, 18–21 October 2005, Château-Thierry.


Duration: 2006–2009 CICRP programme director: Philippe Bromblet, Jean-Marc Vallet

Partnership(s): University of Venice, Athens Institute of Geology and Mineral Exploration, Historic Monuments Research Laboratory (LRMH), restoration companies Lithos (Italy) and Pons-Asini (Germany), Algerian Ministry of Culture, the Supreme Council of Antiquities, the cultural heritage departments and the universities of Boumerdès (Algeria) and Meknes (Morocco)

From 2006 to mid-2009, the CICRP participated in a European Mediterranean cooperation programme entitled MEDISTONE (preservation of ancient MEDIterranean sites in terms of their ornamental and building STONE). The partners worked on the conservation of three large iconic sites: the ancient cities of Cuicul (Djémila, Algeria) and Volubilis (Morocco) and the stones of the Lighthouse of Alexandria (Egypt) retrieved from the water.

Three lines of research have been pursued: the identification of the origins of the stones used, the assessment of deterioration and the development of a stone reconstruction technique.

Publications:

This project gave rise to approximately 20 publications and communications. Several students have collaborated and a thesis was defended at the Université des Sciences de Meknès.

Dessandier D., Antonelli F., Bouzidi R., Bromblet P., El Rhoddani M., Kamel S., Lazzarini L., Leroux L., Vallet J.-M. and Varti-Matarangas M., Guide des pierres du site antique de VOLUBILIS (Maroc), (2010) Publications of Université Moulay Ismaïl, Edited by Saïd Kamel, p. 57.

Dessandier D., Bromblet Ph., Vallet J-M., Cadot-Leroux L., Akarish A., Nageh A. and Shoieb A., ‘Contribution to the study of the building stones and monumental sculptures of Alexandria lighthouse (Egypt)’, Proceedings of the 11th International Congress on Deterioration and Conservation of Stone, Toruń, Poland, org. by N. Copernicus University, edited by Lukaszewicz J. W. and Niemcewicz P., 2008, p. 1189–1196.