The Abbey Newsletter

Volume 7, Number 2
May 1983


Information on Leather Conservation

Last September, at the IIC meeting in Washington, there was an informal meeting of people interested in leather conservation, reported in the October issue of this Newsletter. In April a mailing went out to the people who attended or asked to be put on the list. It contained a record of the discussions, a list of basic publications, a list of names of interested people, and a summary of events and discussions since last September. It was put together by Sonja Fogle, of Washington, DC, on a one-time basis, and much of it is at too technical a level to be useful to library conservators, but some of the more relevant and useful parts are reprinted below.

Note on Chemical Composition [Of Some Substances Used in Leather Conservation]:

Sorbitol is a five -OH group alcohol which absorbs more water than glycerol. Glycerol is the alcohol building block for leather's natural fats and oils; its presence does not interfere with chemical analyses, but its three -OH groups do provide good humectant properties. PEG 400 (polyethylene glycol) has a higher molecular weight than glycerol, and is less hygroscopic. Neat's-foot oil is a distillate of cattle hooves and bones. Bavon ASAK ABP is a solvented, slow-penetrating water repellant advertised as containing alkenyl succinic acid. Haven ASAK 520S is also an alkenyl succinic acid, but one which is modified to contain water as a solvent; it may darken old leather. Neutralfat SSS is a stabilized oleine soap used as an emulsion in leather stuffing. Pliantine Standard is said to be British Museum Leather Dressing (lanolin, oil and beeswax in hexane), whereas Pliantine Special G lacks the wax. The consolidant Pliantex is an acrylic acid ethyl ester in an organic solvent. Ethulose is water-soluble ethyl hydroxyethyl cellulose. Klucel G is hydroxypropyl cellulose, soluble in ethanol and other solvents. Although it has the advantage of being soluble in non-aqueous solvents, some conservators feel the stability of Klucel has not been demonstrated. Others seem satisfied with its aging properties (see F. W. Joel catalog for free reprints).

International Council of Museums (ICOM)

A good deal of interest was expressed in contacting resource and training centers. Todor Stambolov coordinates the ICOM working group on leather, through the Central Research Laboratory in Amsterdam.... Apparently, fewer than 30 people came to the last ICOM leather subcommittee meeting, and there was talk of disbanding it. At least one of the participants... wondered whether they had to join ICOM in order to receive mailings from the working group....

Calls to the Washington, DC office of the American Association of Museums revealed that officially, one has to be an ICOM member to be involved in a working group. In most countries, people join ICOM directly through its national committee. In Canada, memberships are handled by the Canadian Museum Association, but CMA membership is cot required. For U.S. nationals only, AAM membership is a prerequisite for joining ICOM, and an additional $20 in dues must be paid.

Leather Conservation in Europe

On February 3, 1983, Toby Raphael, an ethnographic conservator for the U.S. National Park Service, gave a talk to the Washington Conservation Guild entitled "Recent Development and Innovation in Leather Conservation at Several Leading European Conservation Centers." His trip, supported by a grant from the National Museum Act, allowed two months of study and investigation with the following people: T. Stambolov, H. van Soest and P. Hallebeck at the Central Research Laboratory in Amsterdam; W. Schmitzer at the German Leather Museum in Offenbach; the conservation staff at the National Museum in Copenhagen; S. Keene and H. Ganiaris at the Museum of London; and B. Haines at the BLMRA in Moulton Park....

The techniques being used seemed contemporary and scientific, yet at the same time, conservators have maintained ties with the traditional leather trade and with modern industry. Not all conservators use the same treatments; some conflicting assumptions were noticed. In general however, leather conservation is taken very seriously; treatments have become more standardized and good methods are being developed.

The cooperation between professionals and the integration of resources were inspiring, particularly at the Amsterdam laboratory where three different types of specialist work jointly on any leather problem. There is a theoretical problem-solving staff, an analytical scientific staff and a leather restorer. Numerous standardized examinations are employed to determine specimen condition. Some of the most important include measurements of weight, pH, moisture uptake, total moisture and fat content, fatty acid presence, and estimation of the extent of deterioration as determined by the presence of ammonium sulphate. Using specimen weight and percentage of existing fat, a formula is used to calculate the exact amount of fat to be added to the dressing. Humidification is being used experimentally to swell fibers prior to the application of dressing solutions. Castor and neat's-foot oil dressings have been found to be the most useful, for numerous traditional and modern reasons. Emulsions containing various organic solvents are frequently used for cleaning. A number of new consolidants are being tested. The pH of very acidic specimens is raised using ammonia vapors or buffers. One non-aqueous buffer is glyoxamine, "imidizole."...

Haines of the BLMRA [British Leather Manufacturers' Research Association] is an analytical biochemist who has recently done extensive research on leather preservation, including artificial aging tests [and natural aging].... She cautions against applying dressings as a matter of course; if the leather no longer needs to flex in use, lubricants may be unnecessary. She thinks highly of Bavon ASAK ABP, however, and believes that retanning with alum may be a technique which is applicable to many leathers in addition to bookbindings.

Selected Reading List

[The five references that dealt with ethnographic or wet leather are omitted.]

Cains, Anthony. "Book Conservation Workshop Manual. Part One: Preparation of the Book for Conservation and Repair." The New Bookbinder, 1: 11-25, 19B1. [See esp. p. 12-13.]

Mamas, Betty. "The Structure, Manufacture and Mechanism of Deterioration of Bookbinding Leathers: Part 1. The Structure of Leather." In The Conservation of Library and Archive Materials and the Graphic Arts, pp. 55-65. Preprints of a conference sponsored by the] Society of Archivists and the Institute of Paper Conservation, Cambridge, 1980.

Jamieson, F. Leather Conservation: A Current Survey 1982. The Leather Conservation Centre Ltd. Pisces Press, London, 1982. [Note: the Leather Conservation Centre is now located at Leather Trade House, Kings Park Road, Moulton Park, Northampton NN3 IJD, England.]

Konservering og Restaurering af Laeder, Skind og Pergament. Kompendium fra Nordisk Videreuddannelskursus 3-14 April 1978, Kulturan, Lund, Sweden. Konservatorskolen det Kongelige Danske Kunstskademi, København, 1980. 379 pp. [o.p.] The 26 papers are in Swedish (8), German (7), English (7), and Danish (4). [At least 13 have English summaries. For a list of paper titles in German, see Maltechnik Restauro Vol. 88, No. 3, p. 147 (1982).]

Hofenk de Graaff, Judith. "Hydroxy Propyl Cellulose, a Multi-purpose Conservation Material." ICOM International Committee for Conservation. Preprints of the 6th Triennial Meeting, Ottawa. ICOM Press, Paris, 1981.

McCrady, Ellen. "Brief Survey of Investigations on the Deterioration of Leather" (and) "Research on the Dressing and Preservation of Leather" (and) "Dressing Leaflets Compared." Abbey Newsletter, 5, pp. 22-25 (April 1981).

Reed, R. Ancient Skins, Parchments and Leathers. Seminar Press, London, 1972.

Stambolov, Tudor. "Manufacture, Deterioration and Preservation of Leather: Literature Survey of Theoretical

Aspects and Ancient Techniques." ICOM International

Committee for Conservation. Preprints of the 2nd Triennial Meeting, Amsterdam. ICOM Press, Paris, 1969. [May be available as a separate from the Central Research Laboratory for Objects of Art and Science, Gabriel Metsustraat 8, 1071 EA Amsterdam, Netherlands, for about $10.]

Stambolov, Todor. "Interesting Recent Developments in Leather Conservation" (and) "The Care of Leather Bookbindings." (unpublished leaflets) Central Research Laboratory, Amsterdam, 1982.

Waterer, John W. A Guide to the Conservation and Restoration of Objects Made Wholly or in Part of Leather. Drake Publishers, New York, 1972.

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