Szilágyi András (szerk.): Ars Decorativa 22. (Budapest, 2003)

Márta JÁRÓ: On the History of a 17th Century Noblemans' Dolman and Mantle, based on the Manufacturing Techniques of the Ornamental Metal Threads. Or de Milan, Or de Lyon and Silver of Clay Ornamentations on a ceremonial Costume from the Esterházy Treasury

from a third, smaller, piece of lace, or possibly from accidental contact with some "alien object". We intend that these two metal threads will be subjected to analysis at a later date, after determination of their origin. Manufacturing technique of the metal threads of the lace pieces The metal part of the silver-colour threads of the tulle-based lace (Fig. 12) is composed of a silver-coloured strip on both sides. It is relatively thick, springy (maintaining its helical form), and is wound in S-twist around a Ztwisted linen-thread core.(Fig. 13) The core is today of greenish colour, but was probably originally white. Examining the metal surface under an optical microscope, we observed parallel reddish stripes and the edges of the strip are distorted. On the outer and inner surface of the metal strip, copper was found accompanied by silver; whereas in the middle part of the strip (on its cross-section), only copper could be detected. The results of the material analysis, the parallel scratches on the surface, as well as the springiness of the strip, suggest that the strip was probably formed by flattening a silver-coated copper wire. The distortion at the edges of the strip could have been caused by contact with a tool used to guide the strip in the course of winding it on the core. The description of the method of silver-coating of copper and of wire-drawing can be found in the 16

,h-century work by Biringuccio.

53 The irregularity of the drawplate holes may have contributed to the uneven surface of the wire, resulting in the thinning or complete absence of the silver coating in some of the grooves, and exposing the reddish colour of the copper base. The strip was presumably made from wire by rolling it flat. In this process the metal material became consolidated and springy, and the narrow grooves on the surface became widened into parallel stripes. The springy metal strip in the gold-colour thread is matt on both sides, with parallel scratches, and greenish corrosion-products in places on the surface. The strip is wound in Stwist around a Z-twisted linen core, today of greenish colour, probably originally white. On both sides of the metal strip, and in the crosssection, copper with about 20% zinc was found. Thus according to these findings the material of the strip is a gold-coloured copper-zinc alloy, i.e. brass. Up to now, we have found no description from earlier than the 19th century as to how brass threads for the decoration of textiles were manufactured. For the gold-colour thread the springiness and the scratches on the surface make it probable that here too the strip was prepared from wire by rolling flat. The silver-colour thread of the Brussels lace (Fig. 15) was also made from copper strip silver-plated on both sides, as for the similar threads on the tulle-base type. In the latter case however the strips are wound in S-twist around a Z-twisted silk thread (Fig. 16), originally probably white but today green from the corrosion-products. In this case too, most probably strip prepared from wire by rolling was used. The matt, gold-colour thread of the Brussels lace is made from strip whose base-material is brass (copper alloyed with about 20-24% zinc). The strips were wound in S-twist around a compound silk yarn composed of several threads in Z-twist (today coloured "old-gold", originally probably yellowish). In certain samples a small amount of silver was found, in others a small amount of lead in places. However, these two metals probably found their way on to the surface as a result of contamination. In view of the fact that the garment spent a considerable time underground in damp conditions, it is possible that these two metals became plated on the brass as a result of electrochemical processes. Conclusions from the tests on the metal threads of the lace pieces The base-material of the silver-coloured threads of both lace pieces is copper, and that of the gold-coloured ones is brass. In the literature, the nomenclature and attributed geographical origin of such threads is far from uniform. They were generally called false gold or silver, or "Leon" or "Lyon" type threads. Certain