Fabrics and decoration

July 15th, 2017

Details and explanations regarding fabrics and decorative technology
In the author's original research on Attic Geometric and Orientalising finewares, fabric descriptions were obtained from a limited amount of fragmented vessels or sherds that allowed hand specimen examination. Fabric identifications derived from 86 out of of 391 ceramic artefacts, all coming from the Athenian Agora study collections. The material from the Kynosarges burials and the collections of the British School at Athens was unsuitable for such analysis. Identifications were conducted on existing fractures, cracks or areas along chipped surfaces, with the use of a normal 10X hand lens under artificial light.

Proper fabric examination conducted in the field (Orton et al. 1993) often includes reaction tests with 10% dilute hydrochloric acid, which help in the characterisation of calcareous inclusions. Such test could not be performed on the discussed assemblage due to the destructiveness of this technique. Fabric characterisations provided the following information: a) fabric colours based on the Munsell soil chart (1975), b) description of inclusions, c) density and distribution of inclusions and voids, and finally, d) hardness and feel of fracture. Fabric information was recorded according to the conventions by Orton et al. (1993).

Hand specimen examination was also carried out on 17 unpublished sherds, which were originally selected for destructive analysis and a sampling permit was obtained for that reason from the local authorities (1st Ephoreia of Prehistoric and Classical Antiquities, permit reference ΥΠΑΙΘΠΑ/ΣΥΝΤ/Φ44/64642/2881). This material was used to compare and test the validity of hand specimen characterisations across all assemblages studied in the author's research project. The analysis of these sherds will be discussed in another article, together with the results of archaeometric analyses.

With regard to the study of decorative technologies, the author's research project recorded information related to the nature of external treatments of Athenian Geometric finewares. Information related to simple colour descriptions of decorative elements and coated areas according to the Munsell (1975) soil colour chart, and the identification of coating and slip quality. A similar approach was followed by Ilieva (2014) in the study of regional standardisation of North Aegean G 2-3 wares; however, her approach was not entirely technological as it did not include microscopic analysis of decorated colours and slips, and did not discuss all the parameters related to colour variation.

For simplicity and effective analysis, colour descriptions were divided in three broader colour groups that are explained in the figure below.

The most common colours observed on Attic Early Iron Age pottery belonged to Group 1; however, there appeared to be spots on some vessels with black or brown black decoration that had faded towards red or brownish red colours (Group 2). Similarly, some vessels that were most likely intended to look brownish red or red, exhibited areas along their surfaces that had faded towards orange and reddish yellow colours (Group 3). As it has been observed in the archaeological record, Athenian Early Iron Age potters were capable of controlling firing cycles with the use of ceramic test pieces (Papadopoulos 2003); however, unevenly coloured surfaces would still occur. Such alterations of the final colours were complicated to explain and could have related to a combination of reasons.

Firstly, according to Tite et al. (1982) and Maniatis & Tite (1981) colours of ancient pottery resulted due to different concentrations of iron and manganese elements in paints that were produced from the suspension of clay in water. The unevenly coloured surfaces of some ceramics studied by the author could have been due to the simultaneous use of more than one types of paint per vessel; however, this possibility was highly unlikely. Instead, decorated finewares showed the intention of painters to use a single colour on as many vessels as possible.

Secondly, it was likely that unevenly coloured surfaces resulted due to differences in the density of the paints as they were being delivered by the brush strokes along the vessels’ walls. More specifically, brush strokes tend to leave thicker and darker layers of paint during their initial contact on a blank surface, while colours tend to fade towards the end of a brush stroke. This can result to natural fading in the intensity of the original colour, but the colour would still be the same.

Thirdly, unstable kiln conditions and uneven distribution of heat within kilns could have also been responsible for the unevenly coloured surfaces of some ceramic products. In such cases, paints would have resulted in different colours due to fluctuation of firing conditions (oxidised or reduced), also related to the sequence and duration of each firing cycle.

Fourthly, one needed to bear in mind that in archaeological ceramics colours fade due to post-depositional conditions. Soil humidity and contamination could have affected the external appearance of pots over time and this could have created confusion in the identification of colours on excavated pottery. The effects of deposition on decorative colours have not been studied thoroughly, and therefore, this parameter remained unexplored in relation to the author's original study. It could have been likely that all colour groups were variations of one colour, most likely black, naturally faded in different shades because of long term deposition. Such possibility required further investigation; however, the scope of the original project was not to conduct any relevant corrosion tests.

Based on the above observations, it needed to be clarified that all colours explained in the above figure were visually similar. The chemical composition of paints that were used for the decoration of all vessels was most likely the same (as proven through a separate microscopic study) and variation among colour groups was due to firing. In the author's work, all colours were grouped together based on their intensity and visual appearance by following a sequence from darker to lighter colours: the darker colours comprised Group 1, the intermediate colours Group 2, and the lighter colours Group 3. The colour recorded on each vessel was regarded as the intentional colour that the manufacturer wished to produce. This was the darkest colour on the vessel’s surface and not any other colours observed on faded spots.

Apart from decorative element and coating colours, the author's original project also recorded quality of coatings and slips of decorated finewares. More specifically, coatings were regarded as thick layers of paint that covered a significant portion of the vessel’s surface. Their external appearance could have either been lustrous or matte. By contrast, slips corresponded to two different things. Firstly, genuine slips: these were thin layers of non-iron rich suspension, coming from the original clay used to produce the vessel. Slips were yellow and their external appearance was in most cases lustrous. Secondly, plain washes: for simplicity, these were recorded as thin and matte ‘slips’ and they were typical ‘blank’ surfaces in the colour of the original clay. In general, all finewares had been produced with some sort of external treatment. The least elaborate was the thin matte wash, while the most elaborate was the thick lustrous coating. The definitions used in the study of slip and coating quality are summarised ibelow:

Closed ceramic containers such as amphorae and oinochoai were coated or slipped only on their external surfaces; however, open vessels such as kantharoi and skyphoi were coated or slipped both externally and internally. For simplicity, all coatings and slips recorded and analysed in the project related to the vessels’ external surfaces.