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Grisaille was the first paint applied on stained-glass panels, used in Europe since the twelfth century. Historical written sources described the use of iron and copper together with a high lead-silica base glass in the grisailles production. This project aims to study the evolution of the grisaille paint composition throughout time and the changes in the raw materials used in their production using non-destructive and non-invasive techniques. To achieve this objective, 23 grisaille samples dated from the 13th to the twentieth centuries from nine different countries (Portugal, Poland, United Kingdom, Sweden, Norway, Belgium, Low Countries, Germany, and France) were studied by means of micro particle-induced X-ray emission (μ-PIXE), micro energy dispersive X-ray fluorescence (μ-EDXRF), laser-induced breakdown spectroscopy (LIBS), laser-induced fluorescence (LIF), non-linear optical microscopy (NLOM) in the modality of multiphoton excitation fluorescence (MPEF) and optical microscopy (OM). The results showed that it was possible to identify compositional differences and patterns throughout the samples when compared with literature results. The preference for using copper in central and south-central European countries and the addition of new compounds (CoO, Cr2O3, MnO) as colouring agents since the nineteenth century was verified. The LIBS analyses allow the identification of boron on two samples, confirming the change of base glass components since the seventeenth century. The NLOM-MPEF showed the capability of this technique to measure the grisaille paint layers’ thickness. This non-invasive multi-analytical and complementary approach proves itself efficient in identifying changes in the grisaille’s composition throughout time, which can be interpreted as changes in the raw materials and manufacture used in the production of these paint materials., This research has been funded by the H2020 European project IPERION HS (Integrated Platform for the European Research Infrastructure ON Heritage Science, GA 871034), by the Spanish State Research Agency (AEI) through project PID2019-104124RB-I00/AEI/, by the Fundação de Ciência e Tecnologia de Portugal (project ref. UIDB/EAT/00729/2020, UIDP/00729/2020, LA/P/0008/2020, UIDB/ 04349/2020 and PTDC/ART-PER/1702/2021, researcher grant CEECIND/02249/2021 and doctoral grant ref. PD/BD/136673/2018) and by project TOP Heritage-CM (S2018/NMT-4372) from Community of Madrid.

UID/EAT/00729/2019 PD/BD/136673/2018 Grisaille is one of the oldest and most widely used vitreous paint applied for the production of stained-glass panels and Debitus is one of the most renowned commercial brands whose grisailles are frequently used for the chromatic reintegration in stained-glass window restoration. This article presents the morphological, chemical and thermal analyses of five grisailles from Debitus, to evaluate their properties before and after firing with the objective of knowing their future stability. The characterisation was carried out by optical microscopy, scanning electron microscopy, particle induced X-ray emission, X-ray diffraction, and infrared thermography. This study showed a well-balanced ratio between the different components and a good interdiffusion into the glass, as well as a consistent thermal behaviour between them and with the glass, which indicates the good stability and durability of these materials. publishersversion published

The most innovative procedure for preventive conservation of library holdings, especially those of historical interest, lies in the evaluation of environmental parameters witch have a negative effect on the conservation of such materials. The application of sensors permits for full, accurate and secure monitoring of environmental conditions and allows for the prediction of chemical-physical mechanisms of degradation, as well as of the most suitable procedures for controlling them. The sensors used in the present study were prepared by the sol-gel method and change colour when variations in the evaluated parameters occur. All of the sensors are reversible, reusable and can be regenerated. Temperature, relative humidity, illumination and acidity were the parameters evaluated. In the first stage, conventional apparatus were used to determine the critical ranges of variation for such parameters. Subsequently optical sensors sensitive in such ranges were designed and prepared. These sensors were calibrated and distributed throughout the rooms containing the holdings (approximately 3.200 square meters). The optical response of the sensors (change of colour) was recorded by visible spectrophotometry during the spring and summer of 2009. The use of sensors has the following advantages: low cost, no need for wires or apparatus during exposure, small size, reversibility, and short response time. The resulting data have revealed the environmental conditions of the conservation of the holdings, including environmental acidity, a parameter that could not be evaluated previously through conventional procedures. El procedimiento más innovador de conservación preventiva de los fondos documentales de bibliotecas, especialmente los de carácter histórico, consiste en la evaluación de los parámetros ambientales que afectan negativamente a la conservación de los materiales implicados. La aplicación de sensores permite la monitorización completa, precisa y segura de las condiciones ambientales, predecir los mecanismos quimicofísicos de degradación y los procedimientos más adecuados para controlarlos. Los sensores de este estudio se prepararon por el procedimiento sol-gel y experimentan un cambio de color cuando varían los parámetros a evaluar. Todos los sensores son reversibles, regenerables y reutilizables. Los parámetros evaluados han sido temperatura, humedad relativa, iluminación y acidez. En la primera etapa se utilizaron aparatos convencionales para determinar los intervalos críticos de variación de dichos parámetros. Posteriormente se diseñaron y prepararon sensores ópticos con sensibilidad en esos intervalos, se calibraron y se distribuyeron en las salas de los fondos documentales (aproximadamente 3.200 m2). La respuesta óptica de los sensores (cambio de color) se registró mediante espectrofotometría visible durante la primavera-verano de 2009. El uso de estos sensores presenta las siguientes ventajas: bajo coste, ausencia de cables y aparatos durante la exposición, pequeño tamaño, reversibilidad y tiempos cortos de respuesta. Los resultados han permitido conocer las condiciones ambientales de conservación de los fondos documentales, incluyendo la acidez ambiental que hasta ahora no es posible evaluar con los procedimientos convencionales disponibles.

Several treatments appear in the bibliography to clean the tarnished silver. However, the information about the aspect and efficiency of the cleanings is spread or not completely detailed in these works. With this purpose, a worldwide survey has been carried out to identify of the most common treatments for cleaning tarnished silver and the personal experience of professionals about the frequency of use, the cleaning efficiency, the surface appearance, the application speed, the difficulty and the applicability. This paper contains the results of this survey., The authors kindly acknowledge the help to all professionals who answered the survey. This work has been partially funded by the project CREMEL II Ref. HAR2011-22402, the pre- doctoral FPI grant BES-2012-052716 from the Spanish Ministry of Economy and Competitiveness (MINECO), the FCT post-doctoral fellowship (ref. SFRH/BPD/108403/2015) from the Portuguese Ministry of Science and Technology, and GEOMATERIALES 2-CM Program Ref. S2013/MIT-2914. Finally, the authors want to mention the professional support of the Spanish Network on Science and Technology for the Conservation of Cultural Heritage (TechnoHeritage).