October 1992 Issue 05
A review of the interim symposium of the ICOM leather & related materials group
On the 24th and 25th of June the ICOM interim symposium on 'Leather, Textiles and Related Objects' was held at the Victoria and Albert Museum, drawing ninety-nine participants from fourteen countries. Eighteen papers were given, divided into a scientific part on the first day and applied conservation and case studies on the second.
After an opening address by Elizabeth Esteve-Coll, the subject of leather was introduced by Jonathan Ashley-Smith. He pointed out that this material occurs in many conservation fields, but might be treated in different ways. It is therefore important to bring researchers and conservators of various disciplines together.
The first day revolved around the STEP1 Leather Research Project. This EC funded project aims to identify changes in naturally aged leather and establish an artificial ageing method which brings results closest to natural ageing. A further objective is to develop a standard test method to determine the resistance of leather to ageing and the effects of conservation treatments. Laboratories in France, England, Denmark, Holland and Belgium have been approaching the task from different angles and, after one year, researchers have presented the first results. Artificial ageing tests showed that by shilling the ageing parameters (proportion of pollutants, temperature, humidity etc.) varying degrees of deterioration are produced. The right parameters have yet to be established, eg, UV-radiation and ozone might play a bigger role than previously thought. Interestingly Claire Chahine observed further deterioration of the samples even months after removal from the ageing chambers. In addition, twenty historical leather samples are being analysed by different methods in order to understand their breakdown mechanisms. Little reference has yet been made to the correlation between analytical findings and the physical state of the historical leather samples or their variation in age (samples were taken from the 16th-19th centuries). Nevertheless, research is still in its early stages and further results are awaited with great interest. For practising conservators, this scientific part was some-times not easy to follow. It would have helped on some occasions if abbreviations (eg, in the projected charts) were explained in footnotes or otherwise introduced.
After the talks, a portfolio of early photographs of a Bermondsey tannery from 1862 (in the possession of the V&A) was laid out for viewing. The day ended with a reception appropriately held at the Skinner's Hall (of the Worshipful Company of Skinners).
The next day provided a variety of talks of which I can only mention a few here. Roy Thomson started the morning with a history of the manufacture of leather for clothing. It was surprising how little the processes had changed from early Egyptian times to the 19th century, partly due to the medieval guilds which laid down strict rules on the manufacture of leather. Jan Wouters developed a method of analysing the content of leather for its shrinkage temperature, pH, tannin, fat and minerals using only one 200 mg sample. This procedure still has to be perfected, but is intended to be used by conservators to evaluate the condition of a leather object and decide on the appropriate treatment. Marion Kite gave an overview of skin-related materials incorporated into textiles, and the way they are sometimes disguised or hidden. She stressed how important their detection is for the treatment and storage of the objects.
A fascinating project was presented by a group of conservators from the Instituto Centrale per it Restauro in Rome about the Bandiera di San Giorgio. When I first saw a slide of the 13-14th century silk and leather banner, I was astonished at its 'modern' abstract design, only to learn that nearly all its colourful decoration has been lost in the course of time. Leather parts adhered to a silk support proved to be an incompatible combination; gilded and painted surfaces had flaked off, silk applications have been lost and the banner had undergone numerous restorations (the last one, in 1935, had been documented with photographs). After a lot of detective work to establish the original decoration of the banner, the conservation requires numerous considerations, such as to what extent the original appearance should be restored and how much of the former restoration stitching should be retained so as not to weaken the material further.
Dean Sully reported on the humidifying and reshaping of leather objects in the British Museum and their method of gradual and extended humidification (over several weeks). The potential danger of reshaping and alternative treatments were considered. Sarah White presented the conservation of a Siberian parka as a result of co-operation between a textile and an ethnographic conservator, made possible by a staff exchange between the V&A and the British Museum. The experience and methods of both disciplines were successfully combined to solve the conservation problems of this case.
The symposium, co-ordinated by Pieter Hallebeek and Marion Kite, was a success: well organised, with good time-keeping, enough allowance for questions and a wide and interesting range of subjects. Research about leather is intensifying and current conservation methods are continually being questioned and improved, yet there is still a lot to be learnt. Postprints will be available early next year.
Elizabeth Esteve-Coll; Director,V&A
Jonathan Ashley-Smith; Head of Conservation, V&A
Claire Chahine; Conservation Scientist, Centre de Recherches sur la Conservation des Documents Graphiques, Paris
Roy Thomson; Tanner & Leather Chemist, Northampton
Jan Wouters; Conservation Scientist Koninklijk Institut voor het Kunstpatrimonium, Brussels
Marion Kite; Senior Conservator, Textiles Section, V&A
Dean Sully; Organics Conservation, British Museum
Sarah White; Conservator, Textiles Section, V&A
Pieter Hallebeek, Central Research Laboratory, Amsterdam
1 STEP = Science and Technology in Environmental Projections