Automatic devices for monitoring environmentally induced auto-oxidative degradation of artistic materials in conservation sites

This paper describes an automatic device for in situ and continuous monitoring of the ageing process occurring in natural and synthetic resins widely used in art and in the conservation and restoration of cultural artefacts. The results of tests carried out under accelerated ageing conditions are also presented. This easy-to-assemble palm-top device, essentially consists of oscillators based on quartz crystal resonators coated with films of the organic materials whose response to environmental stress is to be addressed. The device contains a microcontroller which selects at pre-defined time intervals the oscillators and records and stores their oscillation frequency. The ageing of the coatings, caused by the environmental stress and resulting in a shift in the oscillation frequency of the modified crystals, can be straightforwardly monitored in this way. The kinetics of this process reflects the level of risk damage associated with a specific microenvironment. In this case, natural and artificial resins, broadly employed in art and restoration of artistic and archaeological artefacts (dammar and Paraloid B72), were applied onto the crystals. The environmental stress was represented by visible and UV radiation, since the chosen materials are known to be photochemically active, to different extents. In the case of dammar, the results obtained are consistent with previous data obtained using a bench-top equipment by impedance analysis through discrete measurements and confirm that the ageing of this material is reflected in the gravimetric response of the modified quartz crystals. As for Paraloid B72, the outcome of the assays indicates that the resin is resistant to visible light, but is very sensitive to UV irradiation. The use of a continuous monitoring system, apart from being obviously more practical, is essential to identify short-term (i.e. reversible) events, like water vapour adsorption/desorption processes, and to highlight ageing trends or sudden changes of such trends. (C) 2007 Elsevier B.V. All rights reserved.

Archaeological Baltic amber: degradation mechanisms and conservation measures

The aim of this project was to achieve a deep understanding of the mechanisms by which Baltic amber degrades, in order to develop techniques for preventive conservation of archaeological amber objects belonging to the National Museum of Denmark’s collections. To examine deterioration of Baltic amber, a starting point was to identify and monitor surface and bulk properties which are affected during degradation. The way to operate consisted of the use of accelerated ageing to initiate degradation of raw Baltic amber samples in different conditions of relative humidity, oxygen exposure or pH and, successively, of the use of non/micro-destructive techniques to identify and quantify changes in visual, chemical and structural properties. A large piece of raw Baltic amber was used to prepare several test samples for two different kinds of accelerated ageing: thermal-ageing and photo-ageing. During the ageing, amber samples were regularly examined through several analytical techniques related to different information: appearance/colour change by visual examination, photography and colorimetry; chemical change by infrared spectroscopy, Raman spectroscopy and elemental analysis; rate of oxidation by oxygen measurement; qualitative analysis of released volatiles by gas chromatography – mass spectrometry. The obtained results were analysed through both critical evaluation and statistical study. After the interpretation of the achieved data, the main relations between amber and environmental factors during the degradation process became clearer and it was possible to identify the major pathways by which amber degrades, such as hydrolysis of esters into alcohols and carboxylic acids, thermal-oxidation and photo-oxidation of terpenoid components, depolymerisation and decomposition of the chemical structure. At the end it was possible to suggest a preventive conservation strategy based on the control of climatic, atmospheric and lighting parameters in the environment where Baltic amber objects are stored and displayed.

Arqueologia, património e museus na Câmara Municipal de Almeida

Este relatório apresenta as atividades desenvolvidas ao longo do estágio curricular na Câmara Municipal de Almeida, como componente não letiva de formação no Mestrado de Arqueologia da Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa. O estágio teve como principal objetivo a elaboração da carta arqueológica do território das freguesias da Amoreira, Parada e Cabreira, uma parcela do concelho de Almeida. A carta foi elaborada a partir de evidências arqueológicas identificadas em prospeções, de análises da toponímia, da topografia, cartografia, fotografias aéreas e fontes orais do território almeidense. Paralelamente, e no quadro do Museu Histórico-Militar de Almeida, realizou-se um trabalho de organização da reserva arqueológica do município, através da inventariação de todo o espólio arqueológico existente e a elaboração de uma proposta preliminar de conservação preventiva do depósito museal, criando deste modo condições para a receção de novas coleções arqueológicas.

Comunicar con los visitantes: una nueva faceta profesional para los conservadores-restauradores

Heritage resources are more exposed than ever to visitors. For this reason, the transmission of cultural content is not enough: the present situation demands the inclusion of some messages able to foment a sustainable relation between the visitor and the resource. And this can best be achieved with the Preventive Difusion, a sensitizing strategy to inform and persuade visitors about the extreme fragility of the heritage resources. In addition, this strategy is a magnificent tool at the service of the corporate identity of the heritage resources and of the conservators: usually, preventive conservation actions and policies are not clear to visitors. But if they are included into the visit discourse, the public receive an accurate vi-sion of the efforts done in that sense, and it allows them to have a clear idea of these efforts, leading to the image that they have about the resource in question and, by extension, of their conservators.

Guia de Preservação e Segurança da Biblioteca Nacional

Este Guia de Preservação & Segurança da Biblioteca Nacional para salvaguarda do seu acervo e do seu edifício tem por objetivo apresentar orientações, caminhos e rotas para procedimentos e atitudes relativas as questões desta natureza, importantes e vitais nesta era de tantas incertezas. Como base toma-se o saber adquirido no campo da preservação de bens culturais e no campo da política de segurança adotada para acervos bibliográficos e documentais, para usuários e para os edifícios que os abriga. O caráter interdisciplinar que concerne a estes campos do conhecimento sinaliza para o aprimoramento educacional da população como um todo e para nossa memória cultural. Visa a mudança do papel do homem como crítico da natureza, como agente transformador da realidade e de si próprio.

A pintura de quadratura landiana em Belém do Pará

Na segunda metade do século XVIII, Belém viveu um momento de grande expansão econômica, o que se refletiu positivamente na arquitetura, quando foram construídos imponentes templos religiosos no atual centro histórico, dentre os quais a igreja de São João Batista. Esta pesquisa analisou tecnologicamente a pintura de quadratura realizada pelo arquiteto Antonio Landi no interior da igreja de São João Batista, em Belém do Pará, para identificar a tinta utilizada na rara pintura do século XVIII, uma vez que o quadraturista disse ter utilizado em seus trabalhos o pigmento extraído da Arrabidaea chica (H & B) Verlot, popularmente conhecida como carajiru; os processos de alteração sofridos por ela e, assim, obter subsídios para a sua conservação e restauração. O estudo foi realizado em etapas: na primeira, foi feita uma pesquisa histórica envolvendo a literatura sobre as tintas, pigmentos e corantes do período colonial amazônico, utilizados na arquitetura religiosa; sobre a contribuição das ordens religiosas na decoração dos templos; sobre a formação e as atividades de Landi em Belém, e sobre a técnica de pintura denominada de quadratura. Na mesma etapa foi realizado um mapeamento dos danos na pintura e medidos o padrão de cores, por colorimetria, e a temperatura da parede pintada, com câmera de infravermelho. A etapa seguinte foi a investigação laboratorial, que consistiu em analisar a tinta usada por Landi na pintura e o pigmento extraído do carajiru, em microscópio ótico, em microscópio eletrônico de varredura, em difratômetro de raios-X e em espectrômetro de infravermelho. Os resultados possibilitaram a identificação e comparação dos materiais utilizados na pintura de quadratura. E por último, realizou-se um ensaio com a tinta produzida a partir do pigmento extraído do carajiru. A pesquisa histórica contribuiu para o entendimento das tintas, pigmentos e corantes e técnicas de pintura e a interdisciplinaridade facilitou a condução dos procedimentos tecnológicos, permitindo a elaboração de diagnósticos que servem para estabelecer medidas de conservação preventiva e propostas de futuras intervenções de restauro.

O prontuário do paciente na perspectiva arquivística

Pós-graduação em Ciência da Informação - FFC

Aportación de la monitorización mediante redes de sensores y técnicas no invasivas para la conservación preventiva del Patrimonio

La presente tesis doctoral presenta una serie de estudios en el campo del patrimonio basados en metodologías de monitorización mediante redes de sensores y técnicas no invasivas con el objetivo de realizar nuevas aportaciones a la conservación preventiva mediante el seguimiento de los daños de deterioro o la prevención de los mismos. Las metodologías de monitorización mediante el despliegue de redes tridimensionales basadas en data loggers abordan estudios microclimáticos, de confort y energéticos a corto plazo, donde se establecen conclusiones relativas a la eficiencia energética de tres sistemas de calefacción muy utilizados en iglesias de la región centro de la Península Ibérica, abordando aspectos de afección de los mismos en el confort de los ocupantes o en el deterioro de los elementos patrimoniales o constructivos. Se desplegaron además distintas plataformas de redes de sensores inalámbricas procediendo a analizar en esta tesis cuál es la que presenta mejores resultados en el ámbito del patrimonio con el objetivo de una monitorización a largo plazo y considerando aspectos de comunicaciones, consumo y configuración de las redes. Una vez conocida la plataforma que presenta mejores resultados comparativos se muestra una metodología de estudio de la calidad de las comunicaciones en múltiples escenarios de patrimonio cultural y natural con la misma, que servirá para establecer una serie de aspectos a considerar en el despliegue de redes de sensores inalámbricas en futuros escenarios a monitorizar. Al igual que ocurre con las redes de sensores basadas en data loggers, las tareas de monitorización desarrolladas en esta tesis mediante el despliegue de las distintas plataformas inalámbricas ha permitido la detección de numerosos fenómenos de deterioro que son descritos a lo largo de la investigación y cuyo seguimiento supone una aportación a la prevención de daños en los distintos escenarios. Asimismo en el desarrollo de la tesis se realiza una aportación para la conservación preventiva mediante la monitorización con distintas técnicas no invasivas como la termografía infrarroja, las medidas de humedad superficial mediante protimeter, las técnicas de prospección de resistividad eléctrica de alta resolución o la prospección georradar. De este modo se desarrollan distintas aportaciones y conclusiones acerca de las ventajas y/o limitaciones de uso de las mismas analizando la idoneidad de aplicar cada una de ellas en distintas fases de análisis o con distintas capacidades de detección o caracterización de los daños. El estudio de imbricación de dichas técnicas ha sido desarrollado en un escenario real que presenta graves daños por humedad, habiendo sido posible la caracterización del origen de los mismos. ABSTRACT This doctoral dissertation discusses field research conducted to monitor heritage assets with sensor networks and other non-invasive techniques. The aim pursued was to contribute to conservation by tracking or preventing decay-induced damage. Monitoring methodologies based on three-dimensional data logger networks were used in short-term micro-climatic, comfort and energy studies to draw conclusions about the energy efficiency of three heating systems widely used in central Iberian churches. The impact of these systems on occupant comfort and decay of heritage or built elements was also explored. Different wireless sensor platforms were deployed and analysed to determine which delivered the best results in the context of long-term heritage monitoring from the standpoints of communications, energy demand and network architecture. A methodology was subsequently designed to study communication quality in a number of cultural and natural heritage scenarios and help establish the considerations to be borne in mind when deploying wireless sensor networks for heritage monitoring in future. As in data logger-based sensor networks, the monitoring conducted in this research with wireless platforms identified many instances of decay, described hereunder. Tracking those situations will help prevent damage in the respective scenarios. The research also contributes to preventive conservation based on non-invasive monitoring using techniques such as infrared thermography, protimeter-based surface damp measurements, high resolution electrical resistivity surveys and georadar analysis. The conclusions drawn address the advantages and drawbacks of each technique and its suitability for the various phases of analysis and capacity to detect or characterise damage. This dissertation also describes the intermeshed usage of these techniques that led to the identification of the origin of severe damp-induced damage in a real scenario.

Effect of water vapour condensation on the radon content in subsurface air in a hypogeal inactive-volcanic environment in Galdar cave, Spain

Fluctuations of trace gas activity as a response to variations in weather and microclimate conditions were monitored over a year in a shallow volcanic cave (Painted Cave, Galdar, Canary Islands, Spain). 222Rn concentration was used due to its greater sensitivity to hygrothermal variations than CO2 concentration. Radon concentration in the cave increases as effective vapour condensation within the porous system of the rock surfaces inside the cave increases due to humidity levels of more than 70%. Condensed water content in pores was assessed and linked to a reduction in the direct passage of trace gases. Fluctuations in radon activity as a response to variations in weather and microclimate conditions were statistically identified by clustering entropy changes on the radon signal and parameterised to predict radon concentration anomalies. This raises important implications for other research fields, including the surveillance of shallow volcanic and seismic activity, preventive conservation of cultural heritage in indoor spaces, indoor air quality control and studies to improve understanding of the role of subterranean terrestrial ecosystems as reservoirs and/or temporary sources of trace gases.

CONSERVACIÓN PREVENTIVA DE DOCUMENTOS

Por su carácter constitutivo y al estar frecuentemente expuestos a factores y mecanismos de alteración, los documentos en soporte de papel sufren constantes cambios en su composición física y funcional, lo cual pone en peligro la información consignada en ellos. En países de clima tropical como el nuestro, este riesgo es mucho mayor, ya que las condiciones ambientales propician la aparición más frecuente de agentes adversos a la estructura molecular del papel mismo.Por consiguiente, los funcionarios a cargo de la producción, organización y facilitación de documentos públicos y privados, así como quienes conservan materiales de índole particular, tienen la responsabilidad de crear condiciones ambientales, estructurales y administrativas propicias, con el objeto de garantizar la perdurabilidad de sus acervos documentales para las futuras generaciones.Dado que la cultura costarricense usualmente se enfoca en “apagar el fuego” cuando el incendio está en pleno desarrollo, es que se considera prioritario impulsar y propiciar políticas preventivas para que los documentos que se produzcan en las instituciones públicas, surjan y se conserven en condiciones óptimas para su conservación permanente. 

LOS RIESGOS DE DETERIORO DEL PATRIMONIO DOCUMENTAL EN AMÉRICA LATINA

La conservación preventiva se ha convertido en la única vía para salvaguardar la memoria histórica de los pueblos. Existen múltiples definiciones de conservación preventiva, lo que con frecuencia la convierten en centro de discusiones interminables, pero casi todos coincidimos en que por conservación preventiva podemos entender todas las acciones que se dirigen a disminuir el riesgo de deterioro de las colecciones. Y he aquí que el término riesgo ocupa un sitio de gran importancia para la conservación. Entendemos por riesgo la contingencia ó proximidad de un daño, en otras palabras la probabilidad de sufrir un evento peligroso ó indeseable, que en el caso del patrimonio documental se traduce en deterioro o pérdida de valores.El riesgo de deterioro de un documento, esta dado por la relación de dos aspectos, la vulnerabilidad del objeto, y las amenazas a la que está expuesto.

Advanced Spectroscopy for the Study of Colourants in Cultural Heritage

Colourants are substances used to change the colour of something, and are classified in three typology of colorants: a) pigments, b) dyes, and c) lakes and hybrid pigments. Their identification is very important when studying cultural heritage; it gives information about the artistic technique, can help in dating, and offers insights on the condition of the object. Besides, the study of the degradation phenomena constitutes a framework for the preventive conservation strategies, provides evidence of the object's original appearance, and contributes to the authentication of works of art. However, the complexity of these systems makes it impossible to achieve a complete understanding using a single technique, making necessary a multi-analytical approach. This work focuses on the set-up and application of advanced spectroscopic methods for the study of colourants in cultural heritage. The first chapter presents the identification of modern synthetic organic pigments using Metal Underlayer-ATR (MU-ATR), and the characterization of synthetic dyes extracted from wool fibres using a combination of Thin Layer Chromatography (TLC) coupled to MU-ATR using AgI@Au plates. The second chapter presents the study of the effect of metallic Ag in the photo-oxidation process of orpiment, and the influence of the different factors, such as light and relative humidity. We used a combination of vibrational and synchrotron radiation-based X-ray microspectroscopy techniques: µ-ATR-FT-IR, µ-Raman, SR-µ-XRF, µ-XANES at S K-, Ag L3- and As K-edges and SR-µ-XRD. The third chapter presents the study of metal carboxylates in paintings, specifically on the formation of Zn and Pb carboxylates in three different binders: stand linseed oil, whole egg, and beeswax. We used micro-ATR-FT-IR, macro FT-IR in total reflection (rMA-FT-IR), portable Near-Infrared spectroscopy (NIR), macro X-ray Powder Diffraction (MA-XRPD), XRPD, and Gas Chromatography Mass-Spectrometry (GC-MS). For the data processing, we explored the data from rMA-FT-IR and NIR with the Principal Component Analysis (PCA).

Lo studio del microclima indoor per la conservazione preventiva del Patrimonio storico artistico e culturale

La conservazione preventiva degli edifici storici e dei beni custoditi al loro interno rappresenta una sfida ad oggi condivisa a livello internazionale. Tale conservazione dipende da numerose variabili, tra le quali il microclima indoor gioca un ruolo decisivo. Il fine di questa tesi è verificare come lo studio del microclima indoor, supportato dalla simulazione virtuale e dalla conoscenza storica delle evoluzioni dell’edificio stesso (legate a modifiche impiantistiche; architettoniche; d’uso; ecc., nel corso degli anni), costituiscano una base conoscitiva fondamentale, da cui architetti e restauratori possono partire per definire strategie specifiche, volte alla conservazione preventiva del Patrimonio. Per fare questo, l’autore presenta le indagini svolte per tre casi-studio: la Sala 33 della Reggia di Venaria Reale, in provincia di Torino, Italia; la Biblioteca Generale Storica dell’Università di Salamanca, in Spagna; il Portico della Gloria, nartece della Cattedrale di Santiago de Compostela, in Spagna. La metodologia definita e adottata per l’analisi e l’interpretazione dei dati di ciascun caso-studio ha previsto la comprensione e la messa in relazione tra: scelte costruttive; vicende evolutive delle singole architetture; fattori che ne determinano il microclima, letti (o ipotizzati) nelle relative modifiche diacroniche; degrado delle architetture e dei beni che sono custoditi in esse. Infine, uno degli esiti più innovativi della ricerca è stata la definizione di due indici di rischio: sono stati infatti definiti due nuovi indici (Heritage Microclimate Risk -HMR- e Predicted Risk of Damage -PRD-) legati al microclima degli edifici che ospitano beni e manufatti che costituiscono il patrimonio storico artistico e culturale. Tali indici sono stati definiti tenendo conto di tutte le variabili da cui il microclima dipende e dei fattori che ne determinano l’evolversi nel tempo e nello spazio.

Study of the effectiveness of crystal growth modifiers in the prevention of damage due to crystallization of sodium carbonates in stone artworks

The disintegration of stone materials used in sculpture and architecture due to the crystallization of salts is capable of irreparably damaging artistic objects and historic buildings. A number of phosphonates and carboxylates were tested here as potential crystallization modifiers for sodium carbonate crystallization. Precipitated phases during crystallization induced either by cooling or by evaporation tests were nahcolite (NaHCO3), natron (Na2CO3∙10H2O) and thermonatrite (Na2CO3∙H2O), identified using X-ray diffraction. By using the thermodynamic code PHREEQC and the calculation of the nucleation rate it was demonstrated that nahcolite had to be first phase formed during both tests. The formation of the other phases depended on the experimental conditions under which the two tests were conducted. Nahcolite nucleation is strongly inhibited in the presence of sodium citrate tribasic dihydrate (CA), polyacrylic acid 2100MW (PA) and etidronic acid (HEDP), when the additives are dosed at appropriate concentrations and the pH range of the resulting solution is about 8. Electrostatic attraction generated between the deprotonated organic additives and the cations present in solution appears to be the principal mechanism of additive-nahcolite interaction. Salt weathering tests, in addition to mercury intrusion porosimetry tests allowed to quantify the damage induced by such salts. FESEM observation of both salts grown on calcite single crystals and in limestone blocks subjected to salt crystallization tests allowed to identify the effect of these additives on crystal growth and development. The results show that PA seems to be the best inhibitor, while CA and HEDP, which show similar behaviors, are slightly less effective. The use of such effective crystallization inhibitors may lead to more efficient preventive conservation of ornamental stone affected by crystallization damage due to formation of sodium carbonate crystals.

Cyclododecane exposure in the field of conservation and restoration of art objects

PURPOSE: Recent work practices in the conservation and restoration involve the use of cyclododecane (CDD, CAS 294-62-2) to protect fragile artifacts during their handling or transportation. Little is known about its toxicity, and no previous exposure has been reported. A short field investigation was conducted to characterize the exposure conditions to both CDD vapors and aerosols.METHODS: Measurements were conducted in the laboratory of conservation and restoration of the archeological service in Bern (Switzerland). Three indoor and four outdoor typical work situations, either during brush or spray gun applications, were investigated. Measurements were performed on charcoal adsorbent tube and analyzed by a gas chromatograph equipped with a flame ionization detector.RESULTS: Measurements have been conducted during both brush and spray gun applications. Indoor exposures were of 0.75-15.5 mg/m(3), while outdoors exposures were 19.5-53.9 mg/m(3). Exposures appear to be extremely localized due to both physicochemical properties and application methods of the CDD. Vapor exposure increases dramatically with the confinement of the workplace.CONCLUSION: Preventive measures should be undertaken to limit as much as possible these exposures. Field work in confined areas (ditches, underground) is of particular concern. CDD-coated artifacts or materials should be stored in ventilated areas to avoid delayed exposures. [Authors]