The spalling decay of building bioclastic limestones of Provence (South East of France): From clay minerals swelling to hydric dilation

International audienceMedieval historical monuments of the Provence region (South East of France) were erected with bioclastic limestones and display different sensitivities to spalling decay. The present study aims at understanding the physical processes at play as well as the internal properties governing its intensity. Limestones of contrasting sensitivity to spalling were compared to a reference type, unaffected by this decay, by means of petrography, petrophysic, mineralogy, and hydromechanics. The obtained results highlighted that the various sensitivities can be explained by the deformation recorded during water content variation (hydric dilation). A clay fraction was systematically detected within the mineralogical composition except for the reference material, and some swelling layers were identified in ontmorillonite/glauconite mixed layer minerals. A specific quantification procedure based on the combination of transmission electron microscopy coupled to an energy-dispersive X-ray spectrometer (TEM–EDX) and profile modeling of X-ray diffraction patterns was applied. A strong relationship between swelling layer content and hydric dilation of limestones was evidenced and corroborated the spalling sensitivity. Further interpretation of results showed that swelling layers localization within the texture significantly influence hydric dilation kinetics. Eventually, a mechanical softening was measured after water saturation. This behavior seems unrelated to the clay mineral content and its relative influence on spalling should be examined

Matière altérée, couleurs modifiées : apports des techniques analytiques et d’imagerie pour la compréhension des décors originaux sur les plafonds peints médiévaux, l’exemple de la maison du viguier à Puisserguier

Le plafond à la française de l’ancienne maison du viguier à Puisserguier (Hérault) montre d’intéressants restes de polychromies datant du tout début du XVIe siècle. L’état de dégradation avancé de la matière picturale est cependant à l’origine de certaines modifications chromatiques qui ont pu être mises en évidence par le biais d’analyses physico-chimiques et de l’imagerie scientifique. Nous verrons comment ces outils technologiques ont permis la compréhension des processus d’altération de la matière mais aussi comment ils ont joué un rôle fondamental dans la connaissance du décor original et des modifications qu’il a subi depuis sa création jusqu’à nos jours.The French-style ceiling of the former house of the medieval judge in Puisserguier (Hérault) has interesting remains of paintings from the early 16th century. However, advanced ageing of the pictorials is causing chromatic changes which were highlighted by means of physicochemical analysis and technical imaging. We will see how these techniques have constituted a very useful tool for the understanding of material degradation processes and helped to figure out how the original decoration was without the climate modifications it has been subjected to since its creation

Contribution à l'estimation locale d'effusivité thermique par thermographie infrarouge stimulée

International audienceNotre laboratoire s'est spécialisé dans l'étude des altérations affectant les oeuvres d'art telles que les fresques [1,2]. L'effusivité thermique est une quantité thermophysique qui nous permet de repérer des altérations ou de mettre en évidence des contaminations d'espèces chimiques dans ces oeuvres telles que les sels hygroscopiques. Les deux approches présentées ici, basées sur l'analyse de la diffusion latérale de la chaleur suite à une excitation laser locale, permettent d'aboutir à une bonne estimation de cette grandeur thermophysique, ceci indépendamment de l'épaisseur des échantillons et sans prélèvement (ce qui est un atout pour l'analyse des oeuvres d'art)

Thermal Reconversion of Oxidised Lead White in Mural Paintings via a Massicot Intermediate

Lead white is the most ancient and common white pigment used in mural paintings. However, it tends to blacken with time due to its oxidation to plattnerite (\b{eta}-PbO2). Chemical treatments were used but they can put the pictorial layers supports at risks. Hereby we address the possibility of thermally reconverting black plattnerite to white lead carbonates via a massicot (\b{eta}-PbO) intermediate, with a view to developing a restoration procedure using continuous wave laser heating. We first investigated the conditions (temperature, time, and environment) in which pure powders react, before studying mural painting samples. Experiments were made in ovens and TGA and XRD and SEM characterization were achieved. Litharge ({\alpha}-PbO) and massicot were obtained from plattnerite respectively between 564 and 567 {\deg}C and at 650 {\deg}C. Lead carbonates (cerussite, hydrocerussite and plumbonacrite) formed from massicot in wet CO2 below 100 {\deg}C in a few hours. Lastly, when heating plattnerite based mural painting samples, lead species reacted with binders and mortar, yielding massicot, plumbonacrite but also lead silicate and calcium lead oxides. This demonstrates the viability of thermal reconversion of darkened lead in mural, while raising concerns about the formation of several lead species by reaction with mural painting constituents

Analyzing the evolution of deterioration patterns: A first step of an image-based approach for comparing multitemporal data sets

International audienceWhen documenting and analyzing cultural heritage, the monument states can be described by multitemporal data sets, which however present a complication for the elaboration and examination process. This difficulty leads to the necessity to improve the analyze process in order to expand the documentation process and help experts to enrich and share information about the historical buildings. Therefore an approach of change measurement, which supports the chronical comprehension of a building by visualizing and quantifying the dimensional temporal effects was elaborated, where the analyze process of a multitemporal data set was based on the interpretation of depth map images. These maps were obtained by generating ortho images of an object that was created on purpose by setting up an experimentation to acquire a multitemporal data set. This approach is the first step of a wider ongoing research about change detection processes on multitemporal data sets. Index Terms-Change measurements, multitemporal data set, depth map, ortho image, evolution of deterioration patterns

Imagerie numérique et conservation-restauration : état de l’art et perspectives

L’imagerie scientifique est un outil incontournable des sciences de la conservation-restauration. La modification du support de la photographie, devenu numérique, le développement du rendu tridimensionnel qualitatif et quantitatif de l’image ont transformé la photographie technique en un outil d’investigation non destructif à part entière, indispensable et complémentaire des approches physiques et physico-chimiques classiques et en un outil-support de documentation. L’ensemble des développements et travaux menés en imagerie scientifique et sur l’intégration dans des plateformes collaboratives d’annotation sémantique 3D permet, outre une production plus facile de documents, de mettre en synergie les résultats provenant de différentes techniques d’analyse. Elle va modifier, dans un futur proche, l’approche sur le terrain des acteurs de la conservation et conduire à une meilleure synergie interprofessionnelle. Ils auront ainsi la possibilité de mieux mettre en cohérence leurs observations, leurs conclusions quant aux analyses faites à différentes échelles, dans une dynamique temporelle qui intègre les données de la restauration, de son histoire passée. À terme, et par l’intégration des données environnementales, ces plateformes seront un outil de suivi de l’évolution de l’état matériel du bien culturel et aussi de transmission des connaissances vers un public large.Technical imaging has always been an essential tool in conservation science. Thanks to today’s digital photography and its quantitative and qualitative tridimensional aspects, this imaging has become an autonomous and vital nondestructive instrument that complements classic physical and chemical analyses. It is also an essential tool for documentation purposes. Results coming from different techniques of analysis can now be synthesized by means of new developments in technical imaging and their insertion into collaborative 3D semantic annotation platforms. Technical imaging can modify the infield approach of conservation professionals and will help lead to better interprofessional dialogue in the future. Conservation professionals will have the assurance of better consistency in their observations, which can cover different time frames for restoration projects and historical data and conclusions drawn from analyses made at different scales. In the long term and after integration of environmental data, these platforms will become monitoring tools dedicated to following the state of conservation of cultural heritage objects and a tool for transmitting knowledge about these objects to a wider audience

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

Share - Publish - Store - Preserve. Methodologies, Tools and Challenges for 3D Use in Social Sciences and Humanities

Through this White Paper, which gathers contributions from experts of 3D data as well as professionals concerned with the interoperability and sustainability of 3D research data, the PARTHENOS project aims at highlighting some of the current issues they have to face, with possible specific points according to the discipline, and potential practices and methodologies to deal with these issues. During the workshop, several tools to deal with these issues have been introduced and confronted with the participants experiences, this White Paper now intends to go further by also integrating participants feedbacks and suggestions of potential improvements. Therefore, even if the focus is put on specific tools, the main goal is to contribute to the development of standardized good practices related to the sharing, publication, storage and long-term preservation of 3D data

PoPMuSiC 2.1: a web server for the estimation of protein stability changes upon mutation and sequence optimality

ABSTRACT:Journal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe