Electrochemical monitoring of the storage or stabilization of archaeological copper based artefacts in sodium sesquicarbonate solutions

Archaeological copper-based artifacts recovered from wet and salty environments are often stored or stabilized in sodium sesquicarbonate solutions. Modification of the natural patina and development of active corrosion can occur during these processes, which implies the need for monitoring storage/stabilization processes. The focus of the study consists of examining how corrosion potential (Ecorr) measurements and voltammetric curves can contribute in providing information on the effectiveness of storage and stabilization treatments. Particular attention is given to side effects such as the transformation of the corrosion layers

An Ontology to Support Non-Invasive Diagnosis of Heritage Metals

Metal conservators confronted with unknown artefacts rely on previous literature to develop treatment protocols. This search can be tedious given the dissemination of information across corpus of unstructured texts, mainly in the form of research papers and semi-structured databases of artefacts. In order to improve the search of artefacts sharing similar characteristics (metal composition and structure, conservation condition, etc.), this project proposes a hybrid search engine based on a domain ontology. Using a database populated with information resulting from comprehensive investigations of historic and archaeological artefacts, we extracted and selected key concepts and their relations through the use a various lexical analysis tools. Based on this corpus and frequency analysis, we were able to build an ontology of the domain, opening new perspective on information retrieval. Conservators are able to leverage the power of the hybrid search engine to compare their observations on a specific artefact with objects already stored in the database or with indexed research papers. Using keywords to describe corrosion forms they are confronted with, conservators can retrieve artefacts showing similar corrosion phenomena and assess the conservation condition of their artefacts, e.g. diagnosing the stability of metals or determining the location of the limit of the original surface in corrosion product crusts

Optimisation virtuelle d’un décor princier de la fin du xive siècle au château de Germolles (Saône-et-Loire)

La réalité augmentée est actuellement testée au château de Germolles (Saône-et-Loire) – demeure de plaisance de la duchesse de Bourgogne Marguerite de Flandre, épouse de Philippe le Hardi –, afin de retranscrire auprès du grand public les dernières recherches menées sur les peintures murales médiévales redécouvertes dans les années 1970 et en partie restaurées en 1989-1995. Celles-ci ont bénéficié d’un travail de re-documentation conduit avec le soutien technique et financier de l’Action européenne COST COSCH (COlour and Space in Cultural Heritage) et de la direction régionale des Affaires culturelles de Bourgogne - Franche-Comté. Il a permis de déterminer le niveau d’authenticité des peintures, de caractériser les décors présentant des traces de tôles d’étain doré rehaussées de repeints et d’évaluer leur état de conservation. Cet article reprend les résultats obtenus avant de préciser les conditions de mise en place de l’expérience de réalité augmentée. Les difficultés rencontrées sont décrites, comme les solutions techniques apportées. L’application étant d’ores et déjà intégrée au parcours de visite, un premier retour d’expérience des visiteurs du château est présenté, et quelques perspectives sont discutées.Drac Bourgogne - Franche-Comté et Action européenne COST COSC

Estudio técnico de las pinturas murales de Germolles: la contribución de las técnicas de imagen

[EN] The Château de Germolles is one of the rare palace in France dating from the 14th century. The noble floor is decorated with wall paintings that are a unique example of courtly love spirit that infused the princely courts of the time. After being concealed sometime in the 19th century, the paintings were rediscovered and uncovered in the middle of the 20th century and partly restored at the end of the 1990s. No scientific documentation accompanied these interventions and important questions, such as the level of authenticity of the mural decorations and the original painting technique(s) used in the medieval times remained unanswered. The combined scientific and financial supports of COSCH Cost Action and DRAC-Burgundy enabled to study Germolles’ wall paintings using some of the most innovative imaging and analytical techniques and to address some of the questions raised. The study provided significant information on the material used in the medieval times and on the conservation condition of the paintings. The data collected is vast and varied and exposed the owners of the property to the challenges of data management.[ES] El castillo de Germolles es uno de los raros palacios principescos en Francia que data del siglo XIV. La planta noble está decorada con pinturas murales que son un ejemplo único del amor cortés, ese espíritu que se divulgó en las cortes de la época.Ocultadas desde el fin del siglo XIX, las pinturas fueron descubiertas en la mitad del siglo XXy fueron parcialmente restauradas al finalde la década de 1990. No hay documentación científica queacompañelas intervenciones, y cuestiones importantesse quedaronsin repuesta, en particular el nivel de autenticidad de las decoraciones de las paredes, así como lastécnicaspictóricasutilizadasen laépoca medieval. El apoyo científico y económico de la Acción Cost COSCH y de la DRAC de Borgoña permitió elestudio delas pinturas murales de Germolles con algunas de las técnicas de imagen y analíticasmás innovadoras, con tal de responder a algunas de las cuestiones planteadas. El estudio proporcionó informaciónrelevante en lo que se refiere al material utilizado durante la Edad Mediay sobreel estado de conservación de las pinturas. La toma de datos es ampliay variada, y expuso a los dueños de la propiedad al desafío de la gestión de datos.This project would not have been possible without the financial support by DRAC-Burgundy and the COST Action TD1201: Colour and Space in Cultural Heritage (COSCH) (www.cosch.info) which the authors wish to sincerely thank.Degrigny, C.; Piqué, F.; Papiashvili, N.; Guery, J.; Mansouri, A.; Le Goïc, G.; Detalle, V.... (2016). Technical study of Germolles’ wall paintings: the input of imaging technique. Virtual Archaeology Review. 7(15):1-8. https://doi.org/10.4995/var.2016.5831SWORD18715Giovannoni, S., Matteini, M., & Moles, A. (1990). Studies and developments concerning the problem of altered lead pigments in wall painting. Studies in Conservation, 35(1), 21-25. doi:10.1179/sic.1990.35.1.21Manuel, A., Gattet, E., De Luca, L., & Veron, P. (2013). An approach for precise 2D/3D semantic annotation of spatially-oriented images for in situ visualization applications. 2013 Digital Heritage International Congress (DigitalHeritage). doi:10.1109/digitalheritage.2013.6743752Wefers, S., Reich, T., Tietz, B. and Boochs, F. 2016. SIVT – Processing, Viewing, and Analysis of 3D Scans of the Porthole Slab and Slab B2 of Züschen I. In: S. Campana, R. Sopigno, G. Carpentiero and M. Cirillo, eds, CAA2015. Keep the Revolution Going. Proceedings of the 43rd Annual Conference on Computer Applications and Quantitative Methods In Archaeology. Oxford : Archaeopress Publishing Ltd, pp. 1067-1080

L’aluminium patrimonial ::un métal moderne et pourtant méconnu

L’aluminium est omniprésent autour de nous. Sa présence dans notre vie de tous les jours ne doit pas faire oublier qu’il est aussi patrimonial. Les propriétés qui le caractérisent : légèreté, résistance à la corrosion ont assuré son succès industriel mais d’autres comme son aptitude au recyclage a conduit à la disparition de nombreux témoins de l’évolution technologique du métal. Au travers de l’examen d’un certain nombre d’objets patrimoniaux, en particulier du secteur aéronautique, cet article vise à cerner les acquis mais aussi les lacunes qui entourent la connaissance historique du métal et de ses alliages. Les formes de corrosion auxquelles ces matériaux sont sujets sont pour certaines relativement bien connues, alors que d’autres sont encore mal maîtrisées. Le manque de connaissances sur la nature des objets en aluminium et leur état de conservation rend tout diagnostic délicat, remettant ainsi en cause la conservation à long terme des objets associés. Des propositions sont faites pour remédier à cet état de fait

Mise au point d'un traitement cathodique de stabilisation de pieces en alliages d'aluminium degradees par corrosion en milieu aqueux. Etude des risques de corrosion associee. Etude du mecanisme de la corrosion cathodique

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 82058 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Easy-to-use, low-cost electrochemical open-source hardware to analyse heritage metals ::possibilities and limits

Open-source hardware (OSHW), as low-cost and easy-to-use instrumentations, are particularly suited to the needs of the conservation field. This paper presents two OSHWs developed for the diagnosis of heritage metal artefacts. The DiscoveryMat application allows the qualitative analysis of slightly oxidised metals such as copper and aluminium-based alloys, through the standardized monitoring of the variation of their corrosion potential (Ecorr) with time. The Pleco allows the local identification of corrosion products through linear sweep voltammetry (LSV) plots and this contributes to a better adjustment of conservation treatments on metal artefacts covered with heterogeneous corrosion layers through the selective intervention on some corrosion products and the preservation of others. If the Pleco can already be found in the toolbox of some conservation professionals, the DiscoveryMat application is still in its infancy and needs to be developed in the future as a participatory tool

The conservation of historical marine, terrestrial and industrial aluminium objects ::A Review

Only recently (since the 1980s) have conservation professionals become interested in the conservation of the most modern of our heritage metals: aluminum. If the first aluminum alloys in the nineteenth century have good corrosion resistance and are usually well preserved, those produced in the twentieth century are often poorly conserved and require conservation treatment. The level of intervention depends strongly on the nature of the artefact, its size and the message to be conveyed. On large industrial objects, damaged original materials are often replaced by new materials. In a few cases the most innovative conservation techniques (laser cleaning, chrono-amperometric, polarization) have been applied to preserve original material through cleaning and stabilization by extraction of aggressive species

Wall paintings in the Château de Germolles: an interdisciplinary project for the rediscovery of a unique fourteenth-century decoration

International audienc

Mise au point d'un traitement cathodique de stabilisation de pieces en alliages d'aluminium degradees par corrosion en milieu aqueux. Etude des risques de corrosion associee. Etude du mecanisme de la corrosion cathodique

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 82058 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc