Bodies and Glazes of Architectural Ceramics from the Ilkhanid Period at Takht-e Soleyman (North-Western Iran)

Bodies and glazes of tiles from the Ilkhanid period found at the UNESCO World Heritage site of Takht-e Soleyman were studied to identify materials and certain technical characteristics of the architectural ceramics as part of a larger project to establish different productions. In addition, ceramic vessels and technical ceramics excavated at the site were analysed for comparison. µXRF, SEM/EDX, and Raman spectroscopy were used for the material investigations. Qualitative non-invasive µXRF results allowed for categorisation of the glazes and ceramic bodies based on their overall composition. Quantitative analysis by SEM/EDX on a subset of the samples delivered detailed results on the bodies and glazes. Tiles, made from clay or stonepaste, were almost exclusively decorated with a mixed alkaline lead glaze. The PbO content of this type of glaze ranged from 8 wt% to 25 wt%. The clay bodies of some tiles corresponded to the material of the locally used kiln furniture. Moreover, glaze residues preserved on the kiln furniture proved to be from a mixed lead alkaline glaze with a PbO content of 15 wt% to 25 wt%, a composition that is comparable to the tiles’ glazes. For more insights into the local or regional production of the tiles, supplementary in-depth studies including petrographic analysis would be needed to confirm and further specify the results

Ceramic technology. How to characterise ceramic glazes

Glazes add value to ceramic, improve its appearance (colour and shine) and make it waterproof. Through the choice of colours and designs, glazes made ceramics fashionable, even luxurious, and therefore, an object of trade. Each region and ruling dynasty developed its own style or trademark which makes them particularly suitable for dating purposes. Therefore, the study and analysis of glazes offers direct information about the acquisition of technical skills (technology), trade of specific materials (interregional links), migrations and the introduction/adoption of new trends. A ceramic glaze is a thin glassy layer fused to the surface of a ceramic body through firing. The interaction between the glaze and the ceramic body results in the interdiffusion of elements between both. A glaze consists mainly of an amorphous phase, but also includes bubbles, cracks and crystalline phases (undissolved compounds and crystals formed during the firing). Finally, the glazes were also decorated, and a large variety of materials and methods of applying the decorations were used. In this chapter, we present a summary of the technical characteristics of glazes (composition, microstructures and technical requirements), their discovery and use throughout history and decorative techniques. The methodology and analytical techniques to obtain the information are also discussed.Peer ReviewedPostprint (author's final draft

Early Islamic ceramics and glazes of Akhsiket, Uzbekistan

The thesis examines the technical aspects of ceramics and glazes from Akhsiket, a regional capital in the early Islamic period, which was abandoned in the early 13th century. Ceramics and glazes of the time period under discussion (9th - 13th century) in Uzbekistan are understudied, with minimal scientific analysis of the technological processes. These processes include the forming and firing of ceramic vessels, the origin of raw materials used in ceramics and glazes, and decoration methods such as slip painting and colored glazes. A variety of commonly-seen ceramic types have been studied, giving a well-rounded picture of the ceramic assemblage at Akhsiket. Comparison between ceramics from different sites in Uzbekistan, and the development of the technology over four centuries, is possible with the use of chemical and petrographical data obtained with a variety of scientific techniques - primarily the scanning electron microscope. Contemporary glazed ceramics from Kuva and Tashkent, both in Uzbekistan, were also examined for comparison, and to shed light on the transfer of technological and artistic techniques through Central Asia. Typological analysis of Islamic ceramics shows a progression of artistic and technological knowledge from the Middle East to Central Asia during the Arab expansion in the 8th – 9th centuries. Data from chemical and petrographical analysis has shown interesting similarities and differences between ceramic pastes and glazes used at Akhsiket, Kuva and Tashkent. These analyses are used as evidence for relationships in ceramic production and technology in Uzbekistan and by comparison with published data, to ceramics further afield. Along with providing a clearer picture of ceramic production in Uzbekistan, this work provides a new dimension to the discipline of Islamic ceramic studies, demonstrating the importance of archaeological ceramics of the eastern fringes to the understanding of the production of ceramics and the transmission of knowledge and cultural traditions within the Islamic caliphate

Chemical and isotopic analysis in the investigation of glazes from Northern China and the Middle East, 7th-14th centuries AD

Both Chinese and Islamic glazed ceramics played a significant role in the history of ancient ceramic production. Moreover, it was innovation in glazes that made the Chinese and Islamic ceramics constantly innovative in various categories with different manufacturing techniques. This study applies chemical and isotopic analyses to investigate the manufacturing techniques and provenances of different types of glazes from Northern China and the Middle East, and extends the use of Sr isotopic analysis to investigate raw materials and glaze recipes used to making lime/alkaline glazes in Northern China and the Middle East for the first time. By chemical compositions of the lead glazes, the glazing techniques used to produce Chinese Tang Sancai lead glazes and splashed lead glazes from the Middle East have been identified. The mixture of lead oxide plus quartz/quartz sand was used for making both Chinese Tang Sancai glazes and Islamic splashed lead glazes. Besides, for the Chinese lead glazes, the trace element and lead isotopic analyses of them have been effective in grouping glazes made in different production kiln sites, and hence associating the Tang Sancai wares excavated from archaeological sites of unknown origin with their production centres. Furthermore, by comparing the lead isotopic ratios of Islamic lead glazes and those of lead ore deposits, the possible sources of lead used for making lead glazes can be determined, although more than one source was suggested due to the overlap of Pb isotopic ratios of different lead ore sources in some cases. This study is the first time that Sr isotopic analysis has been applied to the lime/alkaline glazes from Northern China and the Middle East. It has revealed that Sr isotopic compositions of lime/alkaline glazes from Northern China and the Middle East have been very effective in providing information on the glaze recipes and characteristics of raw materials used for making them. Based on Sr isotopic compositions, the case study of Nothern Chinese lime glaze has identified that the Yaozhou celadon glaze was probably produced by local ‘Fuping glaze stone’ combined with botanic ash. Besides, the case study of the Middle East alkaline glaze has suggested that the Raqqa ware glaze was probably made by ‘Cenozoic sand’ containing a certain content of limestone grains and feldspar and that botanic ash was used as a flux

Chemical and isotopic analysis in the investigation of glazes from Northern China and the Middle East, 7th-14th centuries AD

Both Chinese and Islamic glazed ceramics played a significant role in the history of ancient ceramic production. Moreover, it was innovation in glazes that made the Chinese and Islamic ceramics constantly innovative in various categories with different manufacturing techniques. This study applies chemical and isotopic analyses to investigate the manufacturing techniques and provenances of different types of glazes from Northern China and the Middle East, and extends the use of Sr isotopic analysis to investigate raw materials and glaze recipes used to making lime/alkaline glazes in Northern China and the Middle East for the first time. By chemical compositions of the lead glazes, the glazing techniques used to produce Chinese Tang Sancai lead glazes and splashed lead glazes from the Middle East have been identified. The mixture of lead oxide plus quartz/quartz sand was used for making both Chinese Tang Sancai glazes and Islamic splashed lead glazes. Besides, for the Chinese lead glazes, the trace element and lead isotopic analyses of them have been effective in grouping glazes made in different production kiln sites, and hence associating the Tang Sancai wares excavated from archaeological sites of unknown origin with their production centres. Furthermore, by comparing the lead isotopic ratios of Islamic lead glazes and those of lead ore deposits, the possible sources of lead used for making lead glazes can be determined, although more than one source was suggested due to the overlap of Pb isotopic ratios of different lead ore sources in some cases. This study is the first time that Sr isotopic analysis has been applied to the lime/alkaline glazes from Northern China and the Middle East. It has revealed that Sr isotopic compositions of lime/alkaline glazes from Northern China and the Middle East have been very effective in providing information on the glaze recipes and characteristics of raw materials used for making them. Based on Sr isotopic compositions, the case study of Nothern Chinese lime glaze has identified that the Yaozhou celadon glaze was probably produced by local ‘Fuping glaze stone’ combined with botanic ash. Besides, the case study of the Middle East alkaline glaze has suggested that the Raqqa ware glaze was probably made by ‘Cenozoic sand’ containing a certain content of limestone grains and feldspar and that botanic ash was used as a flux

Glazed tiles from Lodhi and Mughal northern India: a technological appraisal

Glazed tiles were used by the Lodhis and Mughals to embellish their buildings in northern India from the late fifteenth to seventeenth century. Tile-work from this region and period is understudied, particularly on matters related to its origin and technology. This thesis presents findings of a research undertaken on a series of tiled buildings located at Delhi, Agra, and Punjab in northern India, from the period of Lodhi and Mughal rule. Tile samples from the buildings have been scientifically analysed - mainly using scanning electron microscopy with energy dispersive spectrometry, and electron microprobe microanalysis with wavelength dispersive spectrometry - for their characterisation. Ethno-archaeological studies on related traditional craft industries have been used to build a more accurate rendition of the technologies employed in their manufacture. A field survey of in situ tile-work has been used to correlate stylistic and physical attributes with data determined through analyses. Results from the study show that different methods were utilized for the production of tiles at Delhi/Agra and Punjab. Those of the Delhi type have indigenous features in their technology, while the Punjab specimens are shown to be technologically closer to those from the core Islamic lands. The industry at Delhi is further shown to have evolved locally, developing gradually from the Lodhi to Mughal period, while the Punjab tile industry at the time of the Mughals is demonstrated to be an import, its establishment clearly influenced externally, with the sudden appearance of a new technological style. The tile-work at both places is however determined to be of the same basic character as Islamic tile-work of the stonepaste variety. This study, besides presenting a comprehensive picture on Lodhi and Mughal tiling traditions, provides important new information in the discipline of Islamic ceramic studies, particularly on the development of stonepaste technology and its transfer

Technological study of the seventeenth century haft rang tiles in Iran with a comparative view to the cuerda seca tiles in Spain

The history of polychrome glazed objects in Iran is synchronised with the history of the first known examples of polychrome glazed artifacts. The polychrome glazed bricks of Chughā Zanbīl, dated back to the thirteenth century BC, might be the first evidences of such a claim. This tradition was followed until the fall of the Achaemenids in the fourth century BC, when glazed bricks objects were vastly used to cover the friezes of palaces and important edifices at Persepolis and Susa. Making polychrome glazes on ceramic materials, however, seems to be abandoned until the Islamic period, when polychrome underglaze objects were widely in use in Iran from the tenth century onwards. The first evidences of creating overglaze polychrome decoration was nevertheless achieved on mīnā�ī glazed objects in the thirteenth century AD, which as Abu’l Qasim stated used be originally called haft rang, e.g. ‘seven colours.’ This technique was slightly modified and used throughout the fifteenth and sixteen centuries in Iran, and then was extensively used in the seventeenth century over the Safavid period (1501-1736). In all these types of polychromies, a dark colour line (mostly black) is used to separate various coloured glazes. This technique is still alive and is widely used in decorating the architectural facades of scholastic buildings in Iran. In the twentieth century, art historians attributed this type of polychrome technique to a Spanish style of making polychrome glazed objects called cuerda seca. The only feature by which such an attribution is established is a ‘black line,’ which is used in both techniques of haft rang and cuerda seca for separating coloured glazes. This thesis provides firsthand information about the seventeenth century haft rang tiles in Iran using various analytical approaches, including optical microscopy, wavelength dispersive x-ray fluorescence (WDXRF), x-ray diffraction (XRD), densitometry, ultraviolet visible spectroscopy (UV-Vis spectroscopy), micro-Raman spectroscopy, and energy dispersive x-ray spectroscopy (EDS). Here, optical microscopy was mainly used to have a general idea about the stratigraphy and various layers of the haft rang tiles. WDXRF was however used to respond to the question of the provenance of the tiles as this subject has always been of interest to frame the archaeological context of haft rang tiles. Another issue emphasised in this thesis is the thermal history of the tiles, which was studied by XRD and measuring the density of the bodies’ tiles. This subject was particularly was interesting for me to delve into because multi layer structure of haft rang tiles makes the study of thermal behaviour of the bodies much complicated. On the other hand, the study of the coloured glazes was firstly achieved by UV-Vis spectroscopy, where the possible colourants and network modifiers of the glazes were studied. Micro- Raman spectroscopy, however, presented very notable results about the opacifiers and un-dissolved particles suspended in the glazes’ matrixes. EDS microanalyses were nonetheless carried out to have a general idea about the chemical composition of the glazes and their fluxes, opacifiers, and network formers. ii The results of the aforementioned studies showed that, regardless where they are found, the bodies of the seventeenth century haft rang tiles are local products and are not imported from other centres of tilemaking. Moreover, under the optical microscope three layers of a terracotta body, a white glaze, and coloured glazes could be observed in a single haft rang tile from the bottom up to the top of the tile. In addition, the thermal history of the tiles’ bodies showed that the tiles were not fired most probably at temperatures higher than 1000°C. In fact, the equivalent firing temperature (EFT) of the majority of these tiles was estimated to be between 800 and 1000°C. As far as the white glaze is concerned, it was achieved by dispersing tin oxide particle in an alkali glaze as opacifier. The lead content of the white glazes can be technically associated with the manufacturing white glazes in medieval Iran, where tin and lead was roasted to make an opacifier for alkali glazes. Another issue concerning the white glaze was its maturing temperature, which was estimated to be at about 850°C. The yellow glazes were however achieved by dispersing lead tin yellow particles in a lead-based glaze. The green and brown glazes were practically the yellow glazes in which copper(II) and iron(III) respectively used. The maturing temperature of the yellow, green, and brown glazes was calculated to be roughly placed at 615°C. The blue, violet, and turquoise glazes showed however different behaviour by an alkali matrix in which cobalt(II), manganese(III), and copper(II) had yielded the blue, violet, and turquoise tones. The maturing temperature of these glazes was assessed to be at about 700°C. The black lines did not show to be true glazes due to the high alumina and manganese oxide contents in their composition. The high maturing temperature of about 1150°C of the black glazes revealed very interesting results. This property has certainly been of interest in manufacturing haft rang tiles; that is, when the low temperature glazes were runny enough to be mixed together, the black line was resistant enough to keep separated the glazes in order not to run together. The relatively higher maturing temperature of the white glaze has also been desirable since it does not softened in low temperatures at which the upper coloured glazes were runny and the chance of mixing the white glaze and the upper glazes was substantially lessened. Another subject on which this thesis shed light is the attribution of haft rang technique to the Spanish technique of cuerda seca. In the discussion and final chapters of the thesis, an attempt is made to put together the technological features of these two techniques. What can be at least understood on the evidences exist about these two techniques is that there is no technological reason by which haft rang technique can be attributed to cuerda seca. The use of black line for separating coloured glazes in Iran, as showed in this thesis, has a history much longer the history of cuerda seca. Hence, I have finally suggested that cuerda seca is an inappropriate term to cover the seventeenth century Persian polychrome tiles. The term ‘haft rang,’ which is used for nominating the antecedents of the seventeenth century polychrome tiles, is preferred in this thesis as this term is also widely used in today’s Iran to address this type of polychrome tiles. Parviz Holakooei Ferrara, Italy March 201

Colour and technology in historic decorated glazes and glasses

Historical decorated glass and glazed ceramics are studied with the object to determine the technology of production and to relate it with the optical properties (colour, shine, opacity). Four different case of study are investigated: production technology and replication of lead antimonate yellow glass from New Kingdom Egypt and the Roman Empire, technology of production of polychrome lustre, analyses of Syrian lustre pottery (12th–14th centuries AD) and study of color and dichroism of silver stained glasses. These different coloured glazes or glasses have in common to be produced by the presence of micro or nanoparticles embedded into the glaze which give their special optical effect. Chemical and microstructural analyses are performed using a selection of complementary Microscopic and Spectroscopic techniques that are the most adequate for the analyses of each decoration. Physical optical properties are also modeled and measured by means of UV-Vis spectroscopy. The composition and structure of the different phases formed during the processing of the decorations in historical times is obtained with the object to learn about their stability and processing conditions and to relate them to their optical propertie

An investigation of production technologies of Byzantine glazed pottery from Corinth, Greece in the eleventh to thirteenth centuries. Volume 1 : Text

The century of archaeological excavations carried out at Corinth, Greece have resulted in the accumulation of a collection of Byzantine glazed pottery unparalleled in the Aegean. The site is set apart from others as being one of only a few sites in the Byzantine world where glazed pottery manufacture has been confirmed. The glazed pottery assemblage demonstrates a changing industry there. During the eleventh century local production consisted of brown glazed, unslipped vessels in a conservative range of forms that were in use alongside the imported, fine Constantinopolitan slip painted and polychrome White Wares. By the end of the eleventh century the local industry had established itself and these imports had ceased as a competitor. At this time local pottery production went through a major revolution in terms of decorative techniques and vessel morphology. Instead of the earlier plain glazed products slips and green and brown glazes were used in combination to produce a range of decorative styles each lasting only a generation or so. In this thesis, the development of production technologies of Byzantine glazed pottery manufactured at Corinth between the eleventh and thirteenth centuries are examined using a number of archaeometric techniques: pottery fabrics are examined using ceramic petrography and inductively coupled plasma-atomic emission spectroscopy and their corresponding glazes are investigated using electron probe microanalysis. The data collected were used to establish patterns of pottery production and trade, and in particular explore developments in methods of glazing. A period of transition in glazing technologies is identified, while certain technological practices are shown to be more sophisticated than has previously been acknowledged for the period in question