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Lustre is characterized by a few hundreds of nanometers thick heterogeneous metal-glassy nano-composite film. Silver and copper nanoparticles are dispersed within the outermost layers of the glaze, conferring peculiar optical properties to the whole material. Even though numerous studies have been carried out, many questions regarding the chemical composition, the mechanism of metal reduction and the optical properties of lustre still remain. Synchrotron radiation techniques are suitable for detailed studies on metal-glassy nano-composites. For example, X-ray absorption fine structure spectroscopy (EXAFS) can provide useful information on oxidized phases or atomic clusters dispersed in an amorphous medium, otherwise not achievable with diffraction techniques. In this work, we try to get information on the chemical state and local environment of metal atoms in the lustre and in the blue pigment, in order to achieve a better understanding of the reduction mechanism of different metals present and the manufacturing techniques related to different productions (Hispano-Moorish and Italian Renaissance lustred majolicas). In particular, different samples characterized by lustre and blue decorations only, produced in Spain and in central Italy in XIV–XV cent., are compared. [ABSTRACT FROM AUTHOR]

In the present paper the main results obtained, over a period of more than ten years, from a series of studies concerning the characterization of Italian Renaissance lustred majolicas (from Gubbio and Deruta, Umbria, Italy) are presented. Lustre decoration is a well-known technique, consisting in the application of a thin metallic iridescent film, containing silver and copper nanoparticles, over a previously glazed ceramic object. The technique had its origin in Persia (IX century), was imported by Moorish in Spain, and then developed in central Italy during the Renaissance period. Numerous analytical techniques (among which, ETASS, XRD, UV–Vis, SEM-EDX) have been employed for the characterization of lustred ceramic shards, allowing one to acquire information on both lustre chemical composition and nanostructure. In this way it was shown how some technological parameters, such as the firing conditions, are mandatory to obtain the final result. The presence of a specific marker of the lustre Italian production, i.e., cosalite (Pb 2Bi 2S 5), has been also highlighted. From the study of the ceramic body composition (by means of XRD and ICP-OES and in particular of chemometric techniques) acquired on more than 50 ceramic shards it was possible to discriminate between Deruta and Gubbio production, in this way allowing one to assign objects of uncertain provenance to a specific site. Finally, the most interesting results obtained studying excellent lustred masterpieces from Renaissance belonging to important museums are here presented. In particular, with the use of nondestructive techniques (PIXE, RBS, and portable XRD), the production of Mastro Giorgio Andreoli from Gubbio was investigated. By means of the same analytical approach, one of the first examples of lustre in Italy (the famous Baglioni’s albarello) was examined, and the controversial question of its attribution to Italian production was scientifically faced. [ABSTRACT FROM AUTHOR]

Renaissance lustred majolica shards from Gubbio and Deruta (Central Italy) were investigated in order to point out differences in chemical and mineralogical composition between these two very similar Italian potteries and furthermore to find correlations with the local raw clay materials probably used for their production. Chemical and mineralogical analysis on the ceramic body were performed by ICP-OES (inductively coupled plasma optical emission spectroscopy) and XRD (X-ray diffraction), respectively. Investigation of the ceramic body revealed significant differences on calcium content indicating that it could be used as a marker for the two different productions. A separation of the ceramic shards in groups, on the base of their provenance, has been achieved applying to the data set formed by the chemical compositional data some multivariate techniques, such as PCA (principal component analysis) and HCA (hierarchical cluster analysis). Even the mineralogical composition of the groups shows very interesting features, differing Gubbio production from Deruta one for the presence of several mineralogical species. The investigations carried out on clays that were collected in the two geographical places have confirmed these differences. In fact, the clay materials have a chemical composition coherent with that one found in the shards. Firing tests performed by heating these clay in different conditions (temperature and soaking time) have shown a different behaviour as concerns the formation of the minerals and it is compatible with the shard composition found. From the comparison between the fired clay and the ceramic shards, some assumptions about the firing conditions applied by the ancient potters have been drawn. [ABSTRACT FROM AUTHOR]

The aim of this work is to gain a further insight into the knowledge of the production process of lustre-decorated ancient majolicas. Lustre is a sophisticated technique employed in the decoration of majolicas as used in central Italy during the Renaissance period. It consists of a beautiful iridescent gold or ruby-red thin metallic film, containing silver, copper and other substances and obtained in a reducing atmosphere on a previously glazed ceramic. Nowadays, it is not possible to replicate the outstanding results obtained by the ancient ceramicists, since the original recipes were lost. It is quite interesting to study lustre-production technology by means of analytical techniques now employed for advanced research on materials (XRD, ETAAS, ICP-OES, TEM-EDX-SAED and UV-Vis). In this work, we have focussed our attention on ceramic fragments decorated with both gold and ruby-red lustres, which were difficult to obtain due to complex reduction conditions required and which were a prerogative of Gubbio production. The two lustre colours differ in their chemical composition as well in their nanostructure. The presence of bismuth was disclosed and it was ascertained to be a distinctive feature of the Italian production. [ABSTRACT FROM AUTHOR]

The knowledge of bismuth during the XV and XVI centuries represents an open question since, according to some authors, this element was confused with lead, tin and silver. On the contrary, G. Agricola (1494–1555), the pioneer of mineralogical science in Europe, in his two works (De Natura Fossilium, Lib X, 1546 and Bermannus Sive De Re Metallica Dialogus, 1528) asserts that bismuth was considered as an element distinct from the other metals at that time. This question gave rise to some interest, and von Lippmann in 1930 wrote a treatise dealing with the history of bismuth between 1400 and 1800. In this work we present the results obtained on Italian and Hispano–Moresque shards studied by means of X-ray diffraction, atomic absorption spectrometry with electrothermal atomisation, inductively coupled plasma optical emission spectrometry and scanning electron microscopy. It seems that our work could provide a new and important contribution to this debate, because we found bismuth in lustre composition of Renaissance shards produced in central Italy. Furthermore, we found that it could also be considered as a discriminating element between Italian and Hispano–Moresque productions, useful to assess their origin. [ABSTRACT FROM AUTHOR]

In order to recover the ancient tradition concerning the materials used for the decoration, majolica shards produced during the Renaissance period in Casteldurante, a famous centre for ceramic production in Italy (Marche), have been examined. In the present study, pigments used for the decorations have been investigated by means of inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDX) and diffuse-reflectance UV-Vis spectroscopy. Ochre, lead antimonate yellow, copper-based pigment and smalt have been used as colourants to obtain respectively yellow-orange, yellow, green and blue decorations in accordance with what is reported by the ancient recipes. [ABSTRACT FROM AUTHOR]

Lustre was one of the most sophisticated techniques for the decoration of majolicas during the Renaissance period. Lustre consists of a thin metallic film containing silver, copper and other substances like iron oxide and cinnabar applied in a reducing atmosphere on a previously glazed ceramic. In this way, beautiful iridescent reflections of different colours (in particular gold and ruby-red) are obtained. The characterisation and the study of lustre-decorated majolicas is of great interest for archaeologists, but also offers possibilities for producing pottery with outstanding decoration today, following ancient examples, since nowadays Italian artisans are interested in the reproduction of the ancient recipes and procedures. Moreover, it can even suggest new procedures for obtaining uniform thin metallic films for technological applications. A study has been carried out on ancient lustre layers using numerous different analytical techniques such as XRD, SEM–EDX, TEM–EDX–SAED, ETAAS, ICP–OES, UV–vis reflectance spectroscopy and SAXS. Lustre films were shown to be formed by copper and silver clusters of nanometric dimension. The colour and the properties of the lustre films depend on the elemental composition of the impasto applied to the ceramic surface as well as on other factors like the metallic nanocluster dimension, the firing conditions, the underlying glaze composition and the procedure used. [ABSTRACT FROM AUTHOR]