Ceramics have for various reasons, mostly functional, but also stylistic, different volumetric capacities, depending on the mass, type, and quantity of the substance they contained. Possible uses can be: cooking, dry storage, liquid storage, food preparation, serving (individual or groups), etc. To best describe these characteristics, archaeologists have designed similar approaches to quantify the shape of a vessel. One of the most common approaches was to establish proportions or ratios between different vessel parts, such as the vessel height, rim diameter, maximum vessel diameter, height to shoulder, base diameter, body height, neck height, etc. The major limitation of using proportions or ratios is that they describe exclusively the morphology of the vessels. A classic example is given by A. O. Shepard who used the 'characteristic points of a vessel profile' to calculate 'definitive proportions of independent restricted vessels' (1976: 226, 244). Others, like J. M. Skibo preferred to use a vessel's body parts and proportions in order to shed light to the functional aspect of the vessel (J. M. Skibo 1992). Still others used these ratios as basic numerical values in statistical analysis. As early as 1970's, I. P. Rusanova pioneered a statistical method based on several variables in order to classify the ceramics of the Korchak-Penkovka type (I. P. Rusanova 1976). Later, M. Parczewski renewed the statistical approach by adopting several ratios that reflected the shape of the vessel (Parczewski 1991). Other approaches, favoring the adoption of ratios as a major tool in deciphering the vessel's technological identity have since been made.
Ceramic Proportions
Ceramic Vessels in any culture and time period have been produced in different sizes and shapes. This variety in sizes and shapes allowed archaeologists to implement a statistical approach to the analysis of ceramic vessels, ranging from the numerical description of the morphology of the vessel to the application of complex multivariate statistics such as principal component analysis (PCA), discriminant analysis, chi-square test, cluster analysis, etc. In all cases, the basic preparatory stage was to 'convert' the visual shape of a given ceramic vessel to a string of numerical values quantifying the deviations of a vessel's walls from a normal (cylindrical) shape. The places where the deviation starts were referred to as 'inflection points' situated between the two major ending points of a vessel's wall: at its base and at the rim (A. O. Shepard 1976: 226). In most cases, these points mark the beginning and/or the end of a vessel's body part: bottom, lower body, upper body, shoulder, neck, etc.
The reason behind the 'statistical approach' is in most cases double-foulded: on one hand, the archaeologist wished to have an exact description of the object of study as a precise alternative to the text-based description, and on the other he strongly felt that applied statistics is THE best way to typological classification. Both issues are bound to answer the question related to the technological identity of the ceramic vessel, and implicitly to the social/ cultural identity of the producer.
The ceramics from the Germania-Slavica study area are ranging from a few centimetres high up to large jars of more than half-a-meter high. The diameter of the vessel openings varies as well, with mean diameter values around 17 cm. The task of gathering and agreeing on standardized proportions is made difficult by the existence of different sub-types and also different variants within the same sub-type. The following measurements (.pdf) can be used for the double-conical type vessel: vessel total height, body height, base diameter, maximum diameter, neck diameter, neck height, maximum mouth diameter). These and other measurements can be used further to create proportions or ratios.
October 23, 2007
