T. Pradell and J. Molera’s paper in the Topical Issue (TI) “Ceramics: Research questions and answers” aimed at guiding researchers in the study of archaeological ceramics from excavation to study and preservation in museum collections. Ceramics are ideally suited to identifying and understanding key turning points and continuing traits along the timeline of ancient civilizations. Ceramics have had a widespread distribution reaching every corner of the Ancient World while establishing an unbroken continuity of human existence from the end of the Late Pleistocene epoch (31.000–12.000 calibrated years before present) (Soffer et al. 1993; Nakamura et al. 2001; Boaretto et al. 2009; Farbstein et al. 2012; Wu et al. 2012; Craig et al. 2013) until today. Given their durable nature, ceramics are among the most abundant materials found in the excavations across both geography and time. Therefore, ceramics constitute a valuable historical indicator, providing key archaeological evidence for historical reconstructions given its technological and socio-economic character.

Glazes are responsible for the appearance (colour and brilliancy) of the ceramics, but they also have a function; they make the ceramics waterproof enabling them to contain liquids and food (kitchen and table ware). Glazes added value to the ceramic objects and, through the choice of colours and designs, made them fashionable and in some cases even making them a luxury product and, therefore, an object of trade. With the consequent increase in demand, they were copied, sold at a lower price and, at length, became of common use. Additionally, each region and ruling dynasty developed its own style or trademark of glazed ceramics, which together with their abundance on archaeological sites compared to other materials makes them particularly suitable for dating purposes.

Studies of glazes provide information about their chemical composition, their microstructure, and firing technologies, as well as the type and style of decoration. The characteristics of the glazes are directly related to the latest technical and scientific advances and to fashion. Moreover, analysis of glazes offers indirect information about the acquisition of technical skills, trade of specific materials that cannot be found locally, the connection or the absence of connection between regions and the introduction and adoption of new trends. Both the learning of new technical skills and the availability of the raw materials are necessary for the successful development of a product. However, the adoption of a new glazed ware with the “appearance” of an imported glazed ware is not necessarily associated with the use of the same method of production or materials. The adoption and copy of new designs and colours is often not accurate enough to make them undistinguishable from the original. Consequently, the information obtained from analysing glazes (1) provides a detailed characterisation of the glaze itself, (2) allows for a technological reconstruction and (3) helps to distinguish local productions from imports, especially when combined with the morphological and stylistical classification (i.e. typology).

The existence of any surviving documentation such as literary sources is very important as they provide direct information of the raw materials used and methods followed in the glazed ware production. However, the reconstruction which can be achieved on that basis is partial and does not extend to all the ceramic types and periods. In addition, in many cases, the descriptions are difficult to translate into modern concepts. For example, the materials are often called by names that may have various meanings or are related to local sources unknown today. It is also not uncommon that the texts were not actually written by the potters themselves but by other people who were not directly related to the production itself and who had to interpret what they were told, with more or less success.

Although it is assumed, following an anthropological and ethnological approach, that the methods of production (materials used, processing of the materials, firing protocols) of glazed ceramics were similar to those used in contemporary traditional ceramic workshops, the analysis of the materials unearthed from some earlier historical workshops has demonstrated that this assumption is not necessarily correct (Salinas et al. 2019a).

Consequently, the study and analysis of glazed wares and any material related to the production of glazes is essential, not only for those interested in the technology, but also for those studying inter-regional connections, migrations of people, establishment of trade patterns and trends in diffusion. Finally, the information obtained is also very important in order to design adequate conservation processes and strategies (De Lapérouse 2020, in this issue).

 

 

Pradell, T., Molera, J. Ceramic technology. How to characterise ceramic glazes. 

Archaeol Anthropol Sci 12, 189 (2020). https://doi.org/10.1007/s12520-020-01136-9