Metal Thread Examination

In de zomer van 2014 is een grote collectie 17de-eeuws textiel gevonden in een scheepswrak bij Texel. De collectie is overgedragen aan Museum Kaap Skil te Texel en is later naar de rechtmatige eigenaar, de Provincie
Noord-Holland, gegaan. In het najaar van 2015 is contact gezocht met de Universiteit van Amsterdam, conservering en restauratie van cultureel erfgoed (UvA-C&R) om mee te helpen met het beheer en behoud van het textiel.

This paper presents the first results of the study of an inscribed embroidered aer (dimensions 0.56x0.49 m), on display at the museum of the Monastery of Panagia Tsambika at Archangelos, Rhodes. The textile depicts a moment of the Divine Liturgy that precedes the Communion of the Apostles. It is an excellent and rare example of post-Byzantine ecclesiastic embroidery in the Dodecanese. Silk and metallic threads of various types have been used. Microscopic observation of the morphological characteristics of the threads was key for the better understanding of manufacturing the techniques and technology used in the artefact.

In 2014, a large collection of textile fragments was found in a 17th-century shipwreck (named BZN17) that had sunk in the Wadden Sea, near the island of Texel, The Netherlands. Captured in a time capsule for centuries, this collection represents a unique example of 17th century fashion, comprising over 150 textile fragments, including costumes, parts of costumes and interior textiles. Although buried for centuries, they are in remarkably good condition, which might be related to the archaeological environment and the high quality of the fabrics. Indeed, these are almost entirely made of silk (except one woollen carpet), and embroidered or woven with metal thread. The most striking characteristic of this collection is the well-preserved deep red colour displayed by many of the textiles.
To understand the origin and function of these textiles, as well as their state of conservation for future preservation strategies, it was important to characterize their materials. Hence, a group of 12 objects was selected for evaluation with ultra-high performance liquid chromatography with diode array detector (UHPLC-PDA) and a scanning electron microscope coupled to an energy dispersive x-ray spectrometer (SEM-EDX).
With UHPLC-PDA, coccid insect dyes were identified as the main colorants on the textiles. However, the ratio of their dye compounds seems to have been affected by the maritime archaeological conditions: dcII and flavokermesic acid were not reported in any of the textiles; and an unusually high kermesic acid equivalent was detected, in relation to the major compounds kermesic and carminic acids. Even though American cochineal and kermes could be possibly attributed in some cases, these results substantially hinder the precise identification of the insect sources. Besides these, madder was often found mixed with the insect dyes or in textile parts that are not directly visible on the costumes.
The evaluation of the fibres with SEM-EDX indicated that some fibres show evidence of microorganism attack, and that the majority has preserved their flexibility; although those from fabrics of lower quality (e.g. lining) are more friable. On the metal threads, silver sulphide crystals were observed, and these correspond to the degradation product of silver. Also, gold was detected on few threads, which indicates that they were probably gilded. Due to the corrosion of silver, most gold particles could have been lost in the maritime environment.
While the provenance of these textiles, and the ship that carried them, is still under investigation, the analytical results obtained undoubtedly prove that a very rich finding has been unearthed. Nevertheless, the archaeological conditions certainly had a preponderant influence on their original appearance and this deserves future research.