Programme start: 2012

CICRP programme director: Jean-Marc Vallet

Partnership(s): CNR-ISAC, Italy; LRMH; le Consiglio Nazionale delle Ricerche (Istituto di Scienze dell’Atmosfera e del Clima et Istituto di Chimica Inorganica e delle Superfici); le Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek; la Fundacion TECNALIA Research & Innovation; Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung e.V.; AIDICO; Instituto Tecnológico de la Construcción; RED S.R.L.; NANO TEGO INC.; Bofimex Bouwstoffen B.V.; Metropolitankapitel der Hohen Domkirche Köln – Dombauverwaltung; Opera di Santa Croce Firenze; Eschlimann Restoration Workshop – Painting; T-O-P Oberflächen GmbH; SC DUCT SRL

The ‘nanomatch’ European project (nano-systems for the conservation of immovable and movable polymaterial Cultural Heritage in a changing environment), coordinated by A. Bernardi (CNR-ISAC, Italy), was launched at the end of 2011 for a duration of three years. Its purpose is to develop two conservation products using nanotechnology that can be applied to stone, wood (whether or not painted) and glass, and which provides better compatibility, effectiveness and durability than conventional products, while respecting the environment. The CICRP‘s contribution will be in the context of work evaluating the compatibility of these products, in terms of projects conducted by the LRMH on mural stone and paintings.


Programme start: 2011

CICRP: Philippe Bromblet (director)

Partnership(s): A-Corros (Arles); restorers: Alessandro Ingoglia, Emmanuel Desroches, Olivier Rolland, Sébastien Aze

The CICRP sought on the one hand to define specifications for water bath desalination and on the other to evaluate the possibility of using electrophoresis to optimise the effectiveness of this method.

Several restoration sites have formed the object of an in-depth follow-up to determine, with the help of restorers and architects, the main difficulties encountered in the course of water bath desalination, and to adapt this methodology accordingly. Moreover, a research internship has been created to test electrophoresis. Sections of columns highly deteriorated and contaminated by soluble salts have been used for comparative testing of desalination by static water baths and electrophoresis baths by varying the parameters (intensity of current, electrodes etc.). The results have not revealed higher effectiveness for the electrophoresis method, while confirming the reductions in pH and the attack risks to the stone in the course of the desalination by electrophoresis. Technical improvements (osmotic membranes) are being considered to improve the effectiveness of this technique.

Publications:

  • Internship report of Sabrina Brunel, trainee for the Professional Degree in conservation/restoration of built heritage for Arles (Aix-Marseille University): ‘Contribution of electrophoresis to the desalination of stone by bath in terms of effectiveness and safety’.
  • ‘Water bath desalination, protocols for optimisation’, ICOMOS technical day, Philippe Bromblet, communication.
  • Bromblet Ph., Vergès-Belmin V., Franzen C., Aze S. and Rolland O., ‘Toward an optimization of the specifications for water bath desalination of stone objects’, Salt Weathering on Buildings and Stone Sculptures, Proceedings from the International Conference, 19–22 October 2011, Limassol, Cyprus, 2011, pp. 397–404.

Duration: 2009–2010

CICRP: Katia Baslé (director), Philippe Bromblet

The purpose of this study is to compare the different existing methods of cleaning against that of cryogenics on various materials (leather, paper, plaster) for which cleaning is problematic. Polishing (smoke sponge and micro-aspiration, dual-coloured rubber), fine sanding (glass powder, glass microfibre), microsanding (alumina), laser and the peelables have been tested to eliminate various marks encountered on each support (ink, grease, mould, black crust etc.). The results of the cleaning tests have been visually evaluated with the naked eye, binocular loupe and scanning electron microscope (SEM).

The results highlight the advantages and limits of cryogenics on each material.

Publication:

Internship report Marie-Amandine Bellet, Master of Research 2, Physical Methods Applied to Heritage Materials, University of Bordeaux.


Duration: 2008–2011

CICRP programme director: Katia Baslé

Partnerships(s): Institute of Archaeomaterials Research, UMR CNRS 5060, IRAMAT-CRPAA; University of Bordeaux 3; Materia Viva Laboratory, Toulouse; TRACES Laboratory – UMR 5608 CNRS, University of Toulouse – Le Mirail; Laboratory for Stored Products – LNDS-QUALIS, Bordeaux

Problems of infestation and re-infestation are recurrent in all heritage sectors (museums, historic monuments, archives, libraries) and problematic particularly in historic monuments: diversity of works present, heterogeneity of materials and especially mass treatments, objects that often cannot be transported and/or cannot be dismantled (retables, pulpits, paneling and mural decorations etc.), large-format objects, topography of the grounds, etc.

The use of mass treatments, in situ and under short time frames, has led to the testing of four gases: dimethyl disulfide or DMDS: CH3S-CH3S; hydrogen phosphide or phosphine: PH3; sulfuryl fluoride: SO2F2; and ethanedinitrile: C2N2, as well as the potential physico-chemical alterations on heritage property.

The results were published in 2011: hydrogen phosphide and ethanedinitrile are to be prohibited as they provoke, respectively, the formation of phosphides and nitrates, which particularly corrode copper. DMDS seems satisfactory but presents a major inconvenience due to the prolonged lingering of its strong alliaceous odour. Sulfuryl fluoride yields the best results so long as a filter is used to prevent impurities from getting deposited on the works and altering them.

Publications:

  • Baslé, K., Daniel, F., Mounier, A., Queixalos, I. and Robbiola, L., ‘The disinfestation of historical monuments: Gas substitutes for methyl bromide‘ (forthcoming), in: Proceedings of the CAF (Controlled Atmosphere and Fumigation), Antalya, Turkey, 15–19 October 2012.
  • Baslé K., Daniel F., Mounier A., Queixalos I., Robbiola L., Ducom P., Ciesla Y. and Fritsch J., ‘Gas substitutes for methyl bromide in cultural heritage: disinfestation of historical monuments’, in: Journal of Entomological and Acarological Research, ser. 2 – vol. 43(2).

Programme start: 2006

CICRP: Jean-Marc Vallet (director), Philippe Bromblet

Partnership(s): Aix-Marseille University; Paul Sabatier University, Toulouse; Historic Monuments Regional Department of Archaeology and Conservation (CRMH) Provence-Alpes-Côte d’Azur; Mercantour National Park

The purpose of the programme launched by the PACA Regional Archaeology Department is to establish the degradation kinetics of rock engravings in the Vallée des Merveilles (altitude of sites above 2,200 m) and to establish a predictive model for the evaluation of the risks and speed of total disappearance of the engravings using different benchmark cases. Its goal is to propose methods of conservation and restoration appropriate to the different cases encountered (site, lithotype, type of degradation).

Engraving

Washed out and eroded engraving, with the development of cyanophytes

(Vallée des Merveilles, photo J.-M. Vallet – CICRP)

The work began with a study on the origin of the red surface colouring on the engraved rocks. An on-site and laboratory investigation involving several lots of engravings has revealed that the engraved stones bore different colours (orange, red, purplish), apparently through different processes. Some of these colours were the result of the transformation of the rock bearing the engravings, while others were due to deposits of mater of varied origins. Currently the work is focusing on relative dating for these colourings and the development of different approaches towards understanding the degradation phenomena and their kinetics, with the aim of determining optimum conservation measures.

Publications:

  • Poster from the 14th International Clay Conference (Castellaneta Marina, Italy, 2009)
  • Poster from the 12th International Congress on the Deterioration and Conservation of Stone (New York, United States, 2012)

Programme start: 2003

CICRP: Philippe Bromblet, Jean-Marc Vallet

Partnerships: Meknes Faculty of Sciences (Morocco), CEREGE (Aix-Marseille University)

A joint venture was launched between the Meknes Faculty of Sciences, the city of Meknès and the CICRP to study the deterioration of the ramparts and main rammed-earth monuments of the ancient imperial city. Several sampling campaigns, a university thesis and specialist field investigations have been used to shed light on the materials and construction methods used, as well as assess the primary degradations and determine methods to improve the protection of these structures.

Morocco

Measurement of the speed of sound on a block of stone

before restoration (Volubilis, Morocco) (photo Philippe Bromblet)

Publications:

  • Bromblet P., Vallet J.-M., Ajakane R., Kamel S., Mahjoubi R. and Meunier J.D., ‘Caractérisation de l’enduit dégradé d’une muraille aqueduc de l’ancienne ville impériale de Meknès (Maroc)’, Minbar Ai Jamiaa, 7, Proceedings of the RIPAM 2005, 2007, pp. 236–246.
  • Ajakane R., Kamel S., Mahjoubi R., Vallet J.-M., Bromblet P., Meunier J.D. and Bouadid R. (2007), ‘Caractérisation des matériaux et de l’altération des remparts pour une restauration adaptée : exemple d’une muraille du contrefort de Hri Souani, Médina de Meknès, Maroc’, RehabiMed, 1st Euro-Mediterranean Regional Conference, Present and Future, Barcelona 12–15 July 2007, pp. 453–456.
  • Kamel S., Ajakane R., Mahjoubi R., El Faleh E.M., Vallet J.-M., Bromblet P., Meunier J.D., Noack Y. and Borschnek D., ‘Caractérisation des materiaux de construction des remparts de la medina de meknes : exemple de la muraille de Sidi – Baba (Meknès, Maroc)’, Echanges transdisciplinaires sur les constructions en terre crue, 2. Proceedings of the roundtable of Villefontaine 28–29 May 2005, Editions de l’Espérou, Montpellier, 2007, pp. 23–32.
  • Ajakane R., Kamel S., Mahjoubi R., Vallet J.-M., Bromblet P. and Meunier J.D., ‘Impact de l’altération météorique sur les murailles de la médina de Meknès (Maroc)’, Proceedings of the International Meeting on Mediterranean Architectural Heritage (RIPAM 2005), 26–28 Sept 2005, Meknès, ENSAM, pp. 119–120.
  • Ajakane R, Kamel S., MahjoubiI R., Vallet J.-M., Bromblet P., Bouabib R., Meunier J.D., Noack Y., Borschnek T. and Guillot H., ‘Preliminary studies on the degradations of the Medina’s ramparts of Meknès (Morocco)’, Proceedings of the 10th International Congress on Deterioration and Conservation of Stone, Stockholm, 2004.
  • Kamel S., Mahjoubi R., Arsalan S, Vallet J.-M. and Bromblet P., ‘Chantier expérimental de restauration sur un bâtiment de la Médina de Meknès (Maroc) en vue d’une méthodologie adaptée’, Proceedings of the international symposium Réhabilitation et revalorisation du patrimoine bâti, 23 and 24 May 2011, Skikda, Morocco, T2, pp. 770–782.

Programme start: 2012

CICRP: Fabien Fohrer

Partnerships(s): Grazia Nicosia, conservator-restorer, National Centre of Plastic Arts (CNAP) grant; Yohanna Dechezleprêtre, conservator-restorer

This research has been carried out with and at the instigation of Grazia Nicosia, conservator-restorer and CNAP research assistant, in collaboration with the artist Ian Fabre.

This study aims to test the repellent effectiveness of essential oils used alone or in combination on certain insects currently encountered on this type of material (examples: Anthrenus verbasci, Stegobium paniceum, Gibbium psylloides, etc.).

Concurrently, a study on the chemical and physical harmlessness of these substances is being carried out on the materials traditionally used by artists, such as insects, but also bones, feathers, leather, hair and also metals and textiles. The study of these repellents, their mode of action and their user protocols will make it possible to improve the packaging and storage of these works by reducing the risk of insect infestation.

Publication:

Fohrer F., 2011, ‘Recherche de produits ou molécules de substitution pour la protection des oeuvres patrimoniales’, La lettre de l’OCIM, No. 138, November–December: 21–22.


Programme start: 2008

CICRP: Nicolas Bouillon (director), Fabien Fohrer

Partnership(s): Aurélia Chevalier, doctor of conservation-restoration, Arts et Métiers-Paris Tech

This programme is an offshoot of a larger programme on Stegobium paniceum and focuses on glue-pastes and the risk of insect infestation for traditionally relined paintings. It also encompasses a concurrent entomological study based on infestation test samples of known composition as well as the analysis of glue-pastes by GC-MS in order to correlate their attractiveness according to their chemical composition.

Pictorial layer

Loss of pictorial layer and its original support following a severe infestation

The first conclusions have addressed the type and quantity of flour used as a principal attraction factor and the presence of Venice turpentine as a plasticizer as a possible repelling factor. Physico-chemical analyses are systematically carried out on real samples taken from infested relined paintings restored at the CICRP in order to correlate the degree of infestation of works with the chemical composition of glue-pastes.

This programme also aims to develop a new natural glue-paste formula that is reversible and long-lasting in terms of effectiveness and the risk of insect infestation. This type of adhesive could constitute an alternative to synthetic linings, which can create a number of reversibility as well as compatibility problems with the original materials, and whose degradation processes and their effects are still poorly understood and controlled at present.

Support infestation

Traces of infestation by Stegobium paniceum of a glue-paste relined support

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 : a 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.

Programme start: 2011

CICRP: Philippe Bromblet

Partnership(s): French Heritage Partners Circle, Historic Monuments Research Laboratory (LRMH) (director), VICAT SA

The object of this programme is to tackle questions of restoration for facades decorated with natural cement based plasters in the Marseille region by proposing a restoration plaster suited to the supports and with colours and textures close to those of these 19th-century plasters.

It includes an examination of the sate of conservation and nature of the natural cement based plasters on Marseille facades, a documentary study on this industrial activity of the 19th and early 20th centuries, as well as visits to quarries (Roquefort-la-Bédoule etc.) and factories (ovens) to sample and analyse the raw materials in order to carry out the rare analyses found in the literature.

Facade decoration

Natural cement: facade decoration of the Eglise de la Mission de France carried out in 1860

by the company Désiré Michel, rue du Tapis Vert, Marseille (photo Philippe Bromblet)

The CICRP has participated in the sampling campaign and management of a documentary research initiative on the history of the manufacture of natural cements from the Marseille region.

Publications:

  • ‘Les enduits à base de ciment naturel à Marseille : Identification et restauration’, literature survey carried out by Claire Valageas, research analyst at the French Heritage Partners Circle, 2011.
  • ‘Histoire de l’industrie des ciments naturels dans la région de Marseille’, presentation by Claire Valageas for the ICOMOS technical days (2 and 27 April 2012, Paris) Les ciments naturels dans le patrimoine européen : histoire, propriétés, applications et conservation.

Programme start: 2000

CICRP: Jean-Marc Vallet

For several years the CICRP has been conducting research on the chromatic modifications affecting lead-based paints, particularly their darkening and the role of the environment in such degradation. Also based on experimental work, particularly with samples artificially aged under different conditions (temperature, humidity, UV), these efforts have confirmed that minium (red lead) transforms into a black lead dioxide (plattnerite) in slightly acidic conditions, and that one of the principal factors behind the darkening of this orange mineral is its method of fabrication. For example, the technique employed for heating white lead leads to the formation depending on temperature of crystalline substances of different colours (yellow, like litharge and massicot; and orange, like minium). This thermal reaction is often imperfect, as it is stopped while impurities such as litharge remain. These impurities are much more sensitive to deterioration than minium and easily transform into plattnerite. The work carried out has also shown that irradiation of the surface with a laser emitting near infrared radiation in continuous mode results in the reconversion of the darkening to minium, with benefits in terms of the stability of the phases formed.

Darkening of white lead

Darkening of white lead

(Monastery of Saorge; photo J.-M. Vallet)

The latest efforts have focused on the darkening of white lead, composed of lead carbonates. The first efforts were carried out on samples artificially aged in an environmental weathering chamber and on samples from the Franciscan monastery of Saorge (06). The aim is to gain an understanding of the role of organic binders in the darkening process.

Publications:

There have been many publications (in the journals European Journal of Mineralogy, Phase transition, l’Actualité Chimique and Technè, as well as in congresses (ICOM-CC, LACONA, RIPAM, PNRCC and SFIIC).

These efforts have formed the topic of a doctoral study, a post-doctoral study and four professional and research Masters.)