We studied ancient enamels on gilded copper from a collection of archeological horse harness pendants of the Museo Instituto Valencia de Don Juan (Madrid, Spain) to test the benefits of a new, nondestructive analytical methodology based on chemometric analysis (i.e., Principal Component Analysis, PCA) on micro‐ATR‐FTIR spectral data and chemical quantification using SEM‐EDS. The novelty of this approach was threefold: (i) PCA allowed the discrimination of the different harness pendants of known origin and attributed to the 14th and 15th centuries according to the chemical complex composition, nanostructure, glass weathering, and/or coloring mechanisms of each colored enamel, separately (i.e., red, purple, blue, and white), (ii) it is a cheap, easily available and nondestructive methodology that enables us to (iii) draw archeological conclusions about the quality of the manufacturing process, reassess the chronology of these objects and attempt to attribute them to different workshops according to the different traditional recipes identified. In particular, the enamels were made of alkali and/or alkaline earth lead‐glass with a wide range of chemical compounds in the form of pigments or opacifiers. Two types of coloring mechanisms were identified, colloidal particles such as copper‐ruby for red enamels, and ionic mechanisms such as Fe(II) and Co(II) to achieve a blue pigments; Mn(III) in the purple pigment; and two kind of white enamels were identified, i.e., tin oxide as an opacifier and uranium oxide. In addition, we established the reason for the poor state of conservation of some of the enamels by means of the identification of depolymerization and ion exchanges, well‐known harmful effects of glass weathering, and finally a chronology was assigned for some of these pieces according to the enamel composition.

La correcta identificación de los materiales que conforman los bienes muebles del patrimonio científico-técnico y de las interacciones entre los mismos es necesaria para establecer estrategias de conservación eficaces con criterios de intervención adaptados. En este trabajo se presenta un estudio del estado de conservación, materiales y patologías de la colección de extintores del Museo Nacional de Ciencia y Tecnología. Se ha realizado una base de datos con 56 extintores, documentando cada pieza, tipología y estado de conservación. Los análisis realizados en varias de ellas (por fluorescencia de rayos X y difracción de rayos X) han permitido identificar los materiales de los extintores, en algunos casos del contenido de los mismos, y establecer mecanismos de degradación. En el caso de los extintores de espuma y de agua, se ha mostrado que el agente extintor es altamente corrosivo y ha causado daños severos a la pieza. En estos casos, resulta aconsejable eliminar el contenido si se quiere asegurar una correcta conservación de los extintores.

This work is intended to deal with the problems which arise when illuminanting Paleolithic cave paintings. We have carried out the spectral and colorimetric characterization of some paintings located in the Murcielagos (bats) cave (Zuheros, Córdoba, Spain). From this characterization, the chromatic changes produced under different lighting conditions are analysed. The damage function is also computed for the different illuminants used. From the results obtained, it is proposed an illuminant whose spectral distribution diminishes the damage by minimizing the absorption of radiation and optimises the color perception of the paintings in this cave. The procedure followed in this study can be applied to optimise the lighting systems used when illuminating any other art work

No abstract

No abstract