SAFESILK – Metal salt-induced silk degradation in heritage collections

As one of the most important industrial sectors from the middle ages to the first industrial revolution, the manufacture and dyeing of textiles plays a pivotal role in the West European history of technology. This is reflected in a vast number of textile objects preserved in heritage collections, ranging from everyday clothing and (composite) accessories (e.g. shoes, fans, shawls) to luxurious goods such as tapestries. However, in spite of its exceptional properties as a textile fiber, silk is generally regarded as the natural fiber that is the most vulnerable to degradation. In fact, weighted silks are by far the most rapidly degrading materials in heritage collections.

Left: Cape in black dyed silk (1890-1910, MoMu, inv. MFA59.14.19). Right: details of the decomposing silk fabric.

In the 19th c., a treatment with metals salts was introduced for dyeing and increasing weight. The combination of an aggressive metal salt, of large quantities of silk artefacts kept in museum storage, combined with the fact that this is an understudied problem, poses a threat to silk objects in heritage collections worldwide. To date, no conservation treatment proved effective, and metal-induced silk degradation remains a major concern for museums. For consolidation of silk, enzymes seem promising as they can induce self-cross-linking reactions, forming a macromolecular network at the nanometer scale while avoiding changes in the visual appearance and preventing accelerated future degradation.

The project goals are:

  • To understand, prevent and treat metal salt-induced silk degradation,
  • To develop analytical techniques to model sil degradation,
  • To safeguard the large number of degrading historical silk objects in museum collections

Planned research:

  • Unraveling the degradation pathways and assessing the influence of various harmful internal and external parameters by producing self-synthetized and artificially aged equivalents of historical material, followed by their chemical characterization,
  • The validity of the insights obtained on these ‘mock-ups’ will be benchmarked by analysis of a number of historical study objects. The results will be incorporated into a hands-on decision tool for the everyday collection management of a museum, via the development of a ‘damage function’,
  • Finally, the aptness of two enzyme treatments, recently developed for industry, will be evaluated for the
    consolidation of degrading historical silk fabrics.


The project (N1-250) is funded through the WEAVE programme in collaboration between FWO (The Research Foundation – Flanders) and ARRS (Slovenian Research Agency) and involves:

In collaboration with:

Please contact us for further information or to establish collaboration.

Scientific achievements:

  • ELREFAEY Ibrahim, STRLIČ Matija, KRAŠEVEC Ida, DI GIANVINCENZO Fabiana, KROTOVA Alina, VETTORAZZO Chiara, ORTEGA SAEZ Natalia, VAN DER SNICKT Geert, JANSSENS Koen, MENART Eva. SAFESILK Metal salt-induced silk degradation in heritage collections. 1st conference of the Slovenian node of the European Research. University of Ljubljana, Ljubljana, Slovenia Infrastructure for Heritage Science, 22nd November, 2023 [COBISS.SI-ID 175147011]
  • ELNAGGAR Abdelrazek. Nine principles of green heritage science: life cycle assessment as a tool enabling green transformation. Heritage Science, 2024 12:13 [COBISS.SI-ID 180581123]
  • KROTOVA Alina, VETTORAZZO Chiara, KRAŠEVEC Ida, STRLIČ Matija, MENART Eva, VERKENS Kim, VAN DER SNICKET Geert, ORTEGA SAEZ Natalia, JANSSENS Koen. pXRF screening of damaged silks in museum collections. Technart: Non-destructive and microanalytical techniques in art and cultural heritage : book of abstracts : International conference on analytical techniques in art and cultural heritage, 7.-12. May 2023, Lisbon (p.192) [COBISS.SI-ID 155819267]

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