Review: Conservation of Leathercraft and Related Objects

Interim Meeting ICOM-CC Working Group
Amsterdam
5-8 April 1995

The Interim Meeting of the ICOMCC Working Group for the Conservation of Leathercraft and Related Objects was held within the scholarly surroundings of the Central Research Laboratory (CRL). Centrally placed, the venue was within sight of the Stedelijk, Van Gogh and Rijks Museums, offering delegates the chance to view these magnificent collections.

Interim Meetings of the Working Group occur once in every three years, allowing sufficient time to elapse in order to gather together a variety of papers, covering nearly every aspect of leather and its conservation. This gave me an excellent opportunity to meet colleagues from throughout Europe and North America, each with a distinctly different leather background. The Meeting attracted over 50 delegates from both the public and private sector. They included conservators, scientists, consultants and curators, with specialisms ranging from ethnographic collections to leather bookbindings.

The first day of proceedings overlapped with the final half day of the ICOM-CC Working Group for Graphic Documents Meeting, creating a combined session of the two groups. This provided the Leather Group with an insight into the preservation of parchment documents. Notable papers included: a Smithsonian Institute project to identify the differing characteristics between parchment and imitation parchment paper¹; a method of extracting oil varnish from parchment using a silica gel poultice²; and finally an ingenious method of Willing parchment loss with a water reversible parchment pulp filler³ .

The Conservation of Leathercraft and Related Objects Meeting started with a rather radical case study. The paper outlined a treatment for an eighteenth century gilt leather screen. This involved the complete transfer of the silver, paint and varnish layers from its deteriorated leather ground onto a new support. Innovative techniques developed during the painstaking treatment of the object included methods of facing and backing, similar to those practised by Painting and Textile conservators⁴ .

Other notable case studies included a 'textbook' example of post-treatment preventive conservation from the Canadian Conservation Institute. A rawhide shadow puppet had been conserved before being supported on a storage mount and packed within a purpose built storage/transit container⁵. A bilingual presentation from the Leather Conservation Centre described their recent work at Brodsworth Hall on a set of leather upholstered dining chairs. A treatment of minimum intervention was developed with their client (English Heritage) to preserve the historical significance of the leather's surface, including old gloss paint repairs⁶ .

The problems encountered when mounting large leather wall hangings were examined, with examples ranging from light weight metal frame stretching systems⁷ to the more modest use of Velcro. The use of flexible stainless steel wire arranged into a complex set of curves and manipulated to suggest a human body was successfully used to support an Eskimo sealskin frock. By carefully shaping the wire curves, the form of the object was gently supported without causing excessive tension to the delicate skin⁸. The consequences of unsatisfactory storage and support materials were brought to everyone's attention by Marion Kite, who showed a 'rogues' gallery of inappropriate storage materials and environmental conditions, with their resultant effects on a variety of materials and finishes applied to leather footwear⁹ .

Book conservation was widely discussed by several speakers, including the meeting co-ordinator Pieter Hallebeek, who had undertaken a comparative study into the durability of six new bookbinding leathers. After investigating the results of both forms of hydrolytic and oxidative degradation, the research will focus on setting new standards for the manufacture of bookbinding leathers¹⁰. Other standards shortly to be published came from the Royal Library (Den Haag), with the third version of their directives for leather and parchment bookbindings. The new version will place greater emphasis on individual treatments rather than on single bulk methods. There will also be a section describing suitable conservation materials and simplified pH and ammonium sulphate content tests¹¹ .
A counterbalance to the standardisation talks was a fascinating historical insight into the use of recycled gilt leather wall hangings for lavish folio and bookbindings¹² .

Finally, an extremely informative paper was given by Rene Larsen, who presented the findings of research he had conducted into the deterioration and conservation of vegetable tanned leather. The relationship between the hydrolytic and oxidative breakdown mechanisms, and the rate at which these factors degrade leather, was found to be dependent upon the tannin type and the quality of the leather's tannage. The research concludes by making several recommendations, notably preventive action to identify and conserve objects during the early stages of deterioration¹³ .

During the three-day meeting, delegates were offered an afternoon visit of the Central Research Laboratories facilities. The tour demonstrated the supporting role that the CRL provides in scientific research to all areas concerned with the preservation of Dutch cultural heritage. Research was chiefly focused on the degradation mechanisms of objects, on their identification and composition and on materials and methods for conservation. Other areas covered by the CRL included library and documentation services, preventive conservation, ethical guidelines and research into historical art technology.

This was my first experience of an ICOM-CC Working Group Meeting and I could not fail to be impressed by the diversity of the programme's content and the general quality of papers. I have only had the opportunity to mention a few of the 21 programmed papers and therefore recommend a copy of the post-prints, which are to be published at the end of the year (1995).

References

1. Parchment or parchment paper. Dianne van der Reyden, Mary Baker.
2. A method for extracting oil varnish from parchment. Inna Mokretsova.
3. The conservation of the codex Eykensis: materials, methods, binding and display.
4. The transfer and restoration of an eighteenth century gilt leather screen.Celine Bonnot, Arc-Nucleart Grenoble and Thomas Bilson, Courtauld Institute of Art.
5. Rawhide shadow puppet, treatment, ethical considerations. Diana Dicus, CCI Ottawa.
6. The conservation of some leather upholstery from Brodsworth Hall. Aline Angus, LCC Northampton and Salwa-Victoria Joram, Fachhochshule, Koln.
7. Light weight metal frame stretching systems. Andeas Schulze, Westfalisches Museumsamt Gelsenkirchen.
8. Some remarks on the conservation and exhibition of ethnographic leather objects. Laura Chiotasso and Constantino Sarnelli, Vejle s.n.c Rome.
9. Some conservation problems encountered when treating shoes. Marion Kite, Victoria & Albert Museum.
10. Comparative investigation of six new bookbinding leathers. Pieter Hallebeek, C.L. Amsterdam.
11. Revised directives for the conservation of leather and parchment from bookbindings. Co v.d. Watering, Royal Library Den Haag.
12. Gilt Leather Bookbindings. Eloy Koldeway, Art Historian.
13. STEP/ENVIRONMENT Project. Rene Larson, Kopenhagen.