The intentional use of lead-tin orange in Indian Islamic glazes and its preliminary characterization (Gill & Rehren 2014, Archaeometry, 56) (original) (raw)
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Archaeometry
We describe the historical appearance, composition and texture of a little-known orange pigment in 17th-century northern India. The pigment shares similarities with lead–tin yellow type II, but has between 6 and 7 wt% zinc oxide instead of silica as a minor element in its structure, in addition to the dominant lead and tin oxide. The consistency of its occurrence and composition across several important and highly decorated monuments and relatively wide chronological and geographical ranges of use indicate the controlled and intentional production of this pigment. We propose to use the name lead–tin orange for this material, indicating its similarity to lead–tin yellow but highlighting its independent character and distinct colour.
Revisiting the beginnings of tin-opacified Islamic glazes
The generally accepted theory is that the demand for Islamic glazed pottery started in Abbasid Iraq in the 9th century AD with the production of a range of glazed wares in response to the import of Chinese stonewares and porcelains. However, Oliver Watson has recently proposed that the demand for Islamic glazed pottery first occurred in Egypt and Syria in the 8th century AD resulting in the production of opaque yellow decorated wares. Using a combination of SEM analysis of polished cross-sections, and surface analysis using hand-held XRF or PIXE, Coptic Glazed Ware from Egypt, Yellow Glazed Ware from Syria, and comparable wares from Samarra, Kish and Susa have been analysed. The analyses show that the opaque yellow decoration was the result of lead stannate particles in a high lead glaze, which it is suggested was produced using a lead-silica-tin mixture. The use of lead stannate in the production of yellow opaque glazes is explained in terms of technological transfer from contemporary Islamic glass- makers who continued the Byzantine tradition of glassmaking. It is further argued that the introduction of opaque yellow glazed pottery into Mesopotamia could have provided the social context for the sudden emergence of tin-opacified white glazed pottery in Abbasid Iraq in the 9th century AD. However, in view of the very different glaze compositions employed for the yellow and white opaque glazes, it seems probable that the white tin-opacified glazes used for Abbasid cobalt blue and lustre decorated wares represent a separate but parallel technological tradition with its origins in the production of Islamic opaque white glass.
Journal of Archaeological Science, 2018
The earliest glazed ware in al-Andalus is dated to the Emiral period (c. AD 850-875) and is not until the Caliphate of Córdoba (AD 929-1031) that a distinctive polychrome tin glaze started being produced. A short transition period (c. AD 875-925) in which elaborate monochrome and bichrome transparent glazes wares coexist with polychrome transparent and tin opaque glazed wares has been identified. The existence of a polychrome lead transparent glaze production in al-Andalus wares is demonstrated; it has distinctive composition and methods of production from monochrome and bichrome wares, and shares a distinctive absence of foot and overglaze application of the decorations with the tin-opacified wares. With regard to the possible routes of the introduction of the polychrome lead and tin glazes into the western Mediterranean the Tunisian connection seems completely discarded. Moreover, and although some similarities between the Cordoba and the Abbasid productions such as similar tin glaze recipe and decorative patterns and use of lead glazes, can be traced, the dissimilarities, such as, the use of overglaze decorations, absence of alkali transparent glazes, variances in the tableware shapes and absence of foot, are still more important, and do not support a clear link between them.
Archaeological and Anthropological Sciences, 2017
A small group of opaque yellow glazed sherds has recently been identified among the ceramics excavated at the Islamic city of Madīnat al-Zahrā' near Cordoba, in al-Andalus (southern Spain), which was founded in 936 AD as the seat of the Umayyad Caliphate power. A small group of sherds from Madīnat al-Zahrā', which can be dated to about 960-980 AD, have been examined in polished section in a SEM with EDS attached. These analyses have established that the Madīnat al-Zahrā' sherds were opacified with lead stannate, and not lead antimonate, as was being used to opacify yellow glazed ceramics in Egypt and Tunisia in the 9 th and 10 th centuries AD. Islamic opaque yellow glazed ceramics, with lead stannate as the opacifier, were first produced (Watson 2014), in Egypt and Syria in 7 th /8 th centuries AD, and from there the technology spread eastwards into Iraq and Iran in 9 th century AD, and continued in use in Iran and Central Asia into the 10 th century AD and beyond. However, the question of where these opaque yellow glazed ceramics were produced has not been fully resolved. Because such ceramics are extremely rare in al-Andalus, it seems most likely that they were either imported from Iran or Central Asia, or produced locally by potters arriving from these areas. The study adds one further, yet not fully understood chapter to the story of a persistent glaze technology which has been widely ignored.
Archaeometry
Coloured tiles from two northern Indian monuments were analysed for their body and glaze composition. The results suggest that three different groups of tiles were used, all comprising a stonepaste body with alkali glaze. One group has strong similarities to a major Indian glass group, known as high alumina mineral natron glass, while the other two are similar to Western and Central Asian plant ash glazes, although with much lower lime content. The colorants conform with those usually employed in pre-modern glazes, with lead-tin yellow Type I and Type II for opaque yellow, copper blue-turquoise, cobalt blue, manganese purple, and green through mixing of lead-tin yellow and copper blue.
Archaeometry, 2011
Coloured tiles from two northern Indian monuments were analysed for their body and glaze composition. The results suggest that three different groups of tiles were used, all comprising a stonepaste body with alkali glaze. One group has strong similarities to a major Indian glass group, known as high alumina mineral natron glass, while the other two are similar to Western and Central Asian plant ash glazes, although with much lower lime content. The colorants conform with those usually employed in pre-modern glazes, with lead-tin yellow Type I and Type II for opaque yellow, copper blue-turquoise, cobalt blue, manganese purple, and green through mixing of lead-tin yellow and copper blue.
Islamic and Hispano-Moresque (mú dejar) lead glazes in Spain: a technical approach
Islamic and Hispano-Moresque glazes from the 10th to 15th centuries found in various archaeological sites, most of them workshops, are studied to show the technical evolution of the medieval glazing process. The technology seems to show a simplification: the early Islamic glazes were applied on prefired bodies and after fritting a lead-silica mixture, whereas for the later Islamic productions the raw materials for the lead glazes were not fritted and they were applied over unfired bodies. The same simplified technology was used in the Hispano-Moresque workshops. In the Islamic workshops lead glazes were coloured by adding elements (Fe, Cu, Mn), whereas the múdejar technology simplified the process by using only one recipe to produce pots of different colour. This was achieved by applying the glaze in a different manner (on one side of the pot to obtain yellow or on both sides to obtain green), or using different pastes (already used to produce pottery for different uses). Finally, there are differences between Islamic and Hispano-Moresque tin glazes related to the crystal size of the opacifier (tin oxide crystals), which should indicate some technological differences in temperature, glaze composition and the process to obtain the frits because of the high dependence between viscosity, temperature and crystal nucleation and growth.
Journal of Archaeological Science,Volume 54, Pages 217–227, 2015
Based on micro-Raman spectroscopy (μ-Raman), micro X-ray fluorescence spectrometry (μ-XRF), X-ray diffractometry (XRD) and optical microscopy, this paper presents the results of our analytical studies on the early Islamic pigments used in the Masjid-i Jame of Fahraj, central Iran. Our investigations showed that ultramarine blue and haematite were used as blue and red pigments, respectively. Moreover, huntite was identified as white pigment with which whewellite was associated as a degradation product. Interestingly, the black paint was identified to be mainly composed of black plattnerite mixed with mimetite, hydromorphite and galena. Our geological survey at the Darreh Zanjir mine, located 35 km west of Fahraj, suggested this mine to be a possible source for supplying the black plattnerite. Accordingly, black plattnerite is suggested to be most probably used as a pigment and not to have formed as a degradation product of lead-based pigments.
Pigments and enamelling/gilding technology of Mamluk mosque lamps and bottle
Journal of Raman Spectroscopy, 2012
On-site Raman spectroscopy is used to investigate four mosque lamps and a bottle dating back to the 13-14th centuries (Syria and/or Egypt, Mamluk period) from the Department of Islamic Art, Musée du Louvre, Paris. The pigments and the enamelled glass matrix have been identified in order to discuss their technology. A comparison is made with one masterpiece from the 19th century made by Brocard. The results obtained for blue (lapis lazuli or Co-coloured glass), yellow (Naples yellows or zinc/ chrome yellow), green (mixture of the aforementioned blue and yellow pigments or lead chromate for restorated foot) red (hematite), white (cassiterite or arsenate) and pink (hematite and cassiterite) pigments are presented. The consistency of the pigments period of use/technology with the datation proposed for each artefact is evaluated. For one lamp, the detection of quartz in some places of the hematite-rich glassy layer supporting the gold is related to the search of a physical bonding with the artefact body. Carbon residues in such enamel are consistent with the use of an organic medium to place the enamel powder before the firing.
Characterization of 17th Century Mughal tile glazes from Shahdara Complex, Lahore-Pakistan
Journal of Cultural Heritage, 2013
The glazed tile decorative art was one of the widely used ornamental techniques for the monumental buildings during the Mughal period, in Pakistan. Coloured tile samples from Jahangir tomb were analyzed to know the glaze composition and to identify the colouring phases used at that time. The study was performed using light microscopy (OM), scanning electron microscopy equipped with energy dispersive X-ray analyzer (SEM-EDS), Raman spectroscopy (RS) and electron microprobe analysis (EMPA). These complementary analytical techniques allowed characterizing the samples as alkali glazes made from plant ashes. The results indicated the use of lead-tin yellow type II for yellow glazes, cobalt and copper for blue glazes, mixtures of yellow and blue glazes for the green glazes, manganese for purple glazes, and a transparent glaze layer for white glazes.