Kovács Petronella (szerk.): Isis - Erdélyi magyar restaurátor füzetek 16. (Székelyudvarhely, 2016)
Sor Zita: Digitális nyomatok a gyűjteményekben
Abstracts Eszter Tóth The conservation of a pair of inlaid iron phalerae from the Avarian Period Iron disks of this kind, called phalerae, are bridle ornaments of the late Avarian Period and, accordingly, they could be dated to the 8th century AD. Such inlaid iron disks have been reported from 17 sites in the Carpathian Basin, especially from its western part, but are unattested in sites outside of this area. The bigger disks, like the ones under discussion, were attached to the joint of the brow-band and the cheek piece of the bridle, while the smaller ones decorated the joint of the cheek piece and the noseband. Inlay made of red copper was founded into the ground metal of the phalera made of wrought iron. The inlay was gilded, traces of which could be seen on top of the corrosion. Along the course of the conservation the gilding was revealed on almost the entire surface of the inlaid metal. The disks were found on the outskirts of Sződliget in 2011, during the course of the excavation of a cemetery of the late Avarian Period. The phalerae from the grave of a warrior buried with his well-accoutred horse were lying next to each other in an upside-down position under the skull of the animal. Both of the disks were fragile and porous, the ground metal got delaminated and the composing materials, the iron and the copper alloy, turned into their corrosion products. Under the soil thick copper and iron corrosion products had been developed on the surface of the phalera, which entirely covered the inlaid pattern. The small traces of gilding on the face suggested that the gilding had been removed by the corrosion product of iron almost completely. At first sight the inlay could not be seen on the disks. With X-ray imaging the pattem of the inlay became visible under the corroded surface, but it could be seen more clearly in CT images. They revealed that the design is composed of a net motif framed by a rope motif and divided by stylised foliage motifs into four sections. To determine the manufacturing method of the inlay the CT images taken of the net motif were compared with X-ray images of the same area coming from three other phalerae, and manufacturing simulations were also carried out. Despite these efforts, the original manufacturing technique - wire-inlay or inlay with melting - couldn’t be determined surely. By using energy dispersive X-ray microanalysis in a scanning electron microscope the gilding was analyzed, and it turned out to be made of remarkably pure gold. The significant amount of mercury found in the same sample served as evidence for fire-gilding. After revealing the pattern, portable X-ray fluorescence spectrometry was applied to determine the material of the inlay, which is in fact copper. Since the inlay is entirely covered in gilding, the composition of the inlaid metal could be analyzed exclusively through the gold layer. The conservation of inlaid artefacts is confined to mechanical cleaning because chemical or electrochemical methods can’t be controlled properly, and they can be harmful for the inlay. Shot-blasting seemed to be a proper method for revealing the pattem. Several attempts were made on similarly corroded iron, but these served merely as guidance, because none of the trial pieces were inlaid, or gilded. To gather more experience about the method it was tested on a little piece of the more fragmentary disc as well. The shot blasting unfortunately damaged and destroyed the gilding that remained - contrary to our expectations - and still covered almost the entire surface of the inlaid metal. With attention to securing the gilding, the pattem was revealed by use of a micro grinder and ultrasonic depurator. This process could be observed and controlled by microscope. Before removing the corrosion, consolidation was needed by using a more and more concentrated solution of Paraloid B72 in a 1:1 mixture of acetone-toluene. Tannin dissolved in ethanol was applied to passivate the corroded iron surfaces. Protection of the restored phalera is ensured by the coating of a thin solution of Paraloid B72 in a 1:1 mixture of acetone-toluene. The brightness of this protective layer could be softened with microcrystalline wax. After the conservation the fragments of the incomplete disk were planted into the hollows of a support in order to keep together the artefact in its entirety without the use of adhesives. Eszter Tóth Metal and goldsmith restorer MA Translated by: Eszter Tóth Mária-Márta Kovács The tin objects of the National History Museum of Transylvania The motivation of the present study was the exhibition Tin Art in Transylvania. Use and iconography organized by the National History Museum of Transylvania in the fall of 2014. During the exhibition an opportunity arose for an X-ray fluorescence spectroscopy study (XRF, using a portable Bruker SI TITAN type device) of the very diverse kind of exhibited tin objects selected from the museum’s collection. 137
