Niello

Milano, Castello Sforzesco, Sala della Balla,
18 novembre 2021, alle ore 18,30

Prenotazione obbligatoria scrivendo a fondazione.trivulzio@tiscali.it

https://www.bookcitymilano.it/eventi/2021/largenteria-di-famiglia-i-nielli-trivulzio-storia-tecnica-e-collezionismo

This article examines Roman metal inkwells found at Augusta Emerita. Along with the presentation of a typology, the parts of an inkwell are defined and volume measures are analyzed. Next, we compare images of writing equipment shown on funerary reliefs to writing equipment from grave assemblages. From this evidence, we reconstruct the use of writing equipment associated with inkwells. Finally, we discuss the gender, status, profession and some other aspects of the life of the people who used such rich inkwells.

The „Adelhauser Tragaltar“ – an opportunity for studying materials and technologies of the Carolingian period

The portable altar from Adelhausen monastery in Freiburg (Breisgau, south-western Germany) is known as one of the major works of Carolingian goldsmith’s art in Europe. It bears witness to arts and crafts of a period characterized by a pronounced scarcity of both written sources on technologies applied and well-dated archaeological material on the other side. The altar is nowadays housed in the collections of the Augustinermuseum in Freiburg. In commemoration of Charlemagne’s death 1250 years ago, the custodians of the Museum planned a small exhibition to be created around this altar. During the preparation of this exhibition it became evident that it would be an excellent occasion to examine the Adelhausen portable altar in terms of its technological and material make-up in order to complement the art-historical research conducted. Scientific studies on the material had never been done before and researchers from different disciplines joined in the effort to solve some of the altar’s enigmas. For the scientific studies of the materials the altar was allowed to leave Freiburg for a period of three days in 2013. All analyses had to be performed without any sampling or mechanical intervention of any kind. The analyses were performed in the  XRF XXL-sample chamber of the RGZM archaeometry lab.

The altar consists of a rectangular wooden panel made of oak inlaid in its central part with a slab made from reddish porphyry. The panel is lined on both long sides with blue and red opaque enamelling set in round metal frames reminiscent of continental-style so called “Kreuzemailfibeln”. Framing the central porphyry plate there are silver metal sheets bearing translucent enamel cells in different colours (blue, green, rose and opaque white) as well as a decorative pattern with deepened gilded lines and Niello.

The analytical aim was to characterize the materials in order to identify separate original material from later additions and add information as to the time frame and regional context of the manufacturing of the altar. One important goals was to verify assumptions as to stylistic proximity to contemporaneous enamels from Italy and Belgium on the basis of enamelling technology.

The analysis showed that the gilding was entirely a fire-gilding with mercury in amounts of several percent as typical for this technique. The niello belongs to the silver-copper sulphide type and is still sintered to the plates in contrary to the melting- variety with addition of lead that appears in the 9th century for the first time. The silver is of high quality. With the results on the composition of the different copper alloys building up the cells for the enamelling, it was possible to identify the construction principle of the setting. Several rivets were analyzed that were clearly made from modern material.

X-ray radiography indicated the presence of two small hollow chambers with a faint trace of some organic material. Later CT studies in Freiburg revealed the existence of two hitherto postulated reliquary “chambers”.

An important point was the identification of the glass type as well as colouring and opacifying agents in the enamels. The base of all enamels was soda-silica glass produced with mineral natron as a fluxing agent. No wood-ash or plant-ash glass was detected. One of several varieties of opaque red enamels was made with lead glass. Calciumantimonate was used as an opacifier for blue, turquoise and white enamels while copper-oxide was used for red. Blue is due to a combination of copper and cobalt, while the turquoise enamel is coloured with copper only. Ionic copper is the source of the colour in the translucent green enamels as well. Manganese was added to one of the translucent enamels, probably to decolourize it, but in the end leaving this enamel type with a rather rose tinge.
The information gained from the analytical study formed the basis for comparison with published analyses from Carolingian art works from Italy (San Ambrogio altar) or Dorestad in Belgium (enamelled fibula fragments). It could be stated that there was no match for the glass type(s) used in combination with the colouring or opacifying agents. Several Carolingian “Kreuzemail” fibula from collections in Germany were analyzed as well in order to look for technological affinities. Here, again, the similarities were not convincing.

To summarize: the analyses add considerably to the yet scarce knowledge on Carolingian technology and material traditions. Some assumptions of technological affinities to some of the works in Italy and Belgium were not supported by the analytical findings. In view of the limited information we have, the significance of variation in material and technology can not be assessed sufficiently in terms of workshop ascriptions.