LUSTRE COLOUR AND SHINE FROM THE OLLERIES XIQUES WORKSHOP IN PATERNA (SPAIN), 13TH CENTURY AD: NANOSTRUCTURE,CHEMICAL COMPOSITION AND ANNEALING CONDITIONS*

Lustre is a medieval ceramic decoration, corresponding to a nanostructured thin layer formed by metallic copper and silver nanocrystals embedded in a glass matrix, which required deep knowledge on the part of the artisans with regard to the raw materials used and the kiln conditions. Their empirical knowledge led to the achievement of colourful lustre decorations ranging from reddish to yellowish or even greenish, some of them with a metallic shine with an associated purplish iridescence. Lustre ceramics dating from the 13th century from the Olleries Xiques workshop in Paterna (Spain) have been studied, linking their chemical composition and nanostructure with their colours and shine. Two kinds of nanostructures are found, yellowish lustre decoration constituted by a silver metal–glass nanocomposite, and reddish lustre decoration constituted by metallic copper nanocrystals and copper oxide nanocrystals; in some cases, metallic copper nanocrystals covered with an oxidized shell of CuO and partly Cu₂O have been found. However, even with significant amounts of copper oxide, the lustre still exhibits a copper metal‐like shine. The bluish iridescence observed at a specular angle in the lustre could not be explained completely by means of the chemical composition, and metallic silver nanoparticle light scattering is proposed as a possible explanation.     

Composition of the Lustre Pigment Used in the Production Of 13th Century AD Raqqa Lustreware from Syria

The very rare find of the relic of the original lustre pigment attached to the glazed surface of a sherd of 13th century ad Raqqa type lustreware from Syria has been analysed using a combination of analytical scanning electron microscopy (SEM), micro‐X‐ray diffraction (XRD) and Rutherford backscattering spectroscopy (RBS). The composition of the pigment relic inferred from these analyses is shown to match those of recipes for lustre production given in the early treatises by Jazbir Ibn Hayyan (c. ad 721–c. ad 815) and Abū'l Qasim (ad 1301). Similarities and differences between this 13th century ad Syrian pigment and pigments used in the ninth century ad in Iraq, in the 14th century ad in Islamic and Hispano‐Moresque Spain, and in the 16th century ad in Renaissance Italy are discussed.     

THE EVOLUTION OF LUSTRE CERAMICS FROM MANISES (VALENCIA,SPAIN) BETWEEN THE 14TH AND 18TH CENTURIES

A set of 33 fragments of lustre‐decorated ceramics uncovered during an archaeological excavation in Manises (Valencia, Spain) have been studied. These ceramics were produced in Manises from the 14th to the 18th century. This well‐dated set of ceramic shards represents the diversity of Manises lustre production and is a complete time sequence of reference for the technological analysis. Texture analysis of the glazes has been carried out by SEM–EDAX, the inner and outer surfaces of the lustre decorations being analysed with non‐destructive ion beams by PIXE and RBS, and also by high‐resolution electron microscopy. The results are compared with other lustre productions and the time trend of the microstructures, glaze and lustre composition is analysed. It is concluded that Sn was used to opacify glazes until the beginning of the 17th century and that changes in the lustre microstructure occurred around ad 1500.     

LUSTRE-DECORATED CERAMICS FROM A 15TH TO 16TH CENTURY PRODUCTION IN SEVILLE*

A set of 17 fragments of ceramics have been uncovered on the occasion of excavations of a workshop in Triana near Seville. These ceramics are typical of objects that are not commonly encountered in present collections in spite of intensive production during the 15th–16th centuries. Chemical and mineralogical analyses have been performed using various techniques (X-ray fluorescence and diffraction, SEM, ion beam analyses). The majority of the ceramic sherds represent the diversity of the Seville production; three fragments recovered in the same archaeological context were not locally produced and belong to the production of eastern Spain (Valence area). The ceramic bodies of the Seville sherds are compatible with the use of clays from the Guadalquivir valley. The glaze and the lustre decoration are comparable to those produced in eastern Spain. These conclusions are based on data that represent the production of a single workshop in Seville; the scatter of the data is due to variations in the processing and/or to alterations during the five centuries of burial of the ceramic fragments.     

Lustre Recipes from A Medieval Workshop in Paterna

The discovery of the workshop ‘Les Olleries Xiques’ in Paterna has provided a unique opportunity to analyse the raw materials, and in particular the recipes used in the production of the lustre decorations. Chemical and phase analyses of lustre raw materials and of lustre decorations belonging to the workshop pottery are shown. A comparison with existing ancient documentation on lustre recipes is also presented.     

Vietnamese (15th Century) Blue‐And‐White,Tam Thai and Lustre Porcelains/Stonewares: Glaze Composition and Decoration Techniques*

EDS, X‐ray fluorescence, Raman spectroscopy, thermal expansion–shrinkage measurement and scanning electron microscopy were applied to determine the elemental components, structural phases and glazing temperatures of the transparent glazes, blue underglaze and overglaze tam thai (including gold‐like lustre) decorations from the 15th‐century Vietnamese porcelains/stonewares found at the Chu Ðâu–My Xa kiln site and in the Cù Lao Chàm (Hôi An) cargo. The ancient technology for colouring the glazes is discussed. The various blue tones in the underglazed décor result from cobalt‐containing manganese ore, with the intentional addition of iron oxide. The overglaze copper‐green and the gold‐like lustre were obtained by dispersing copper in lead‐based glass. The red colour was made using hematite dispersed in lead‐rich flux.     

WHERE DID THE LUSTRE TILES OF THE SIDI OQBA MOSQUE (ad 836–63) IN KAIROUAN COME FROM?*

Metallic lustre decoration of glazed ceramics is a very special kind of ornament, because its colours change with the observational conditions. In diffused light, they can be green, brown or ochre–yellow. In specular reflection, they show an associated coloured metallic shine (blue, golden‐yellow or orange). The lustre tiles at the Sidi Oqba Mosque in Kairouan still have no defined origin (possibly Kairouan and/or Mesopotamia). Physicochemical analyses of eight Kairouan lustre tile samples and four Mesopotamian lustre pottery samples show that the Kairouan tiles probably came from Mesopotamia, from a major production centre, possibly Baghdad, Samarra or Basra.