M. Járó - L. Költő szerk.: Archaeometrical research in Hungary (Budapest, 1988)

Analysis - JÁRÓ Márta, GONDÁR Erzsébet: Mediaeval membrane threads used for weaving and embroidery

5.13. Gilt-leather threads The data obtained from morphologically examining the gilt-leather threads are summarized in Table 4. Table 4 Results of the morphological examination of the gilt-leather threads No. Origin Dating Core Twist Strip Width (mm) No. Origin Dating Material Colour Twist Strip Width (mm) 44. Arabia 10-12th cc. silk yellow Z 0.50 45. Byzantine 10-11th cc. silk yellowish Z 0.45 46. Sicily 14th c. flax white S 0.50 47. Turkey ? silk yellow z 0.40 The number of samples is not enough for drawing conclusions. It is, however, very interesting that gilt-leather threads on silk core are Z twisted and originate from the Far—East. 6. Gilding of the membrane and leather strips Our investigations concerning the method of gilding are not yet finished. Up till now, using microscopy and optical emission spectroscopy the threads could be grouped as follows: 1. güding forms a more or less uniform surface layer and there is no silver underneath; 2. güding forms a more or less uniform surface layer with a silver layer under it; 3. gilding has survived in traces on the sÜver layer; 4. gold may be detected only by material tests (with silver); 5. no gold is to be traced, only silver. According to our assumptions for threads in types 1 and 2, gold foÜs could have been used while for those in types 3 and 4 gold powder may have been applied. This state needs to be prooved.In the first group we can find the gUt leather strips. Thick embroidery threads (C category) belong to the second group. Up to now only one sÜver membrane thread has been found among the samples analysed. 7. Conclusions On the basis of our experience we consider that morphological examinations render possible the differentiation of membrane threads. By measuring the width "oflhe strips we were able to establish 3 main groups and two borderline groups. Gilt-leather threads form a separate group. The examinations showed that further differentiation is possible on the basis of data conœrning the way in which the strips are wound, the twisting of the core, and the method of güding. The aim of our further investigations is a more precise grouping of these threads using the results of morphological examinations and material tests.