[Nhcoll-l] deterioration of study skins in natural history collections

[Bock, Steffen]

Dear colleagues:
I would like to solicit your advice on a project that we are undertaking at the natural history museum in Berlin, Germany (Museum für Naturkunde, MfN) - myself, Steffen Bock, collections manager and Christiane Quaisser, the head of our collections. The project is about the deterioration processes in skins and hides of mammal collections, in particular on flat study skins (not in mounted or stuffed specimens). The huge part of our skins are brittle and crumble and as easily hand-tearable as paper. The last 2 years, I did my master's thesis about this topic, yet many questions remain. I found out that over 80 % of the flat skins in several German and Swiss collections are in such bad conditions. There are few publications on this topic; most of the literature investigates degradation processes in tanned leather and parchment, but these skins are untanned - in fact the original preservation technique/method for these skins is not really known but we suspect the use of potash alum (so-called white leather, tawing) or sulfuric acid (pickling) and salts. In the literature we found mention that excess acids from the preservation methods are the main reasons for skin decay (missing or insufficient deacidification after tawing/tanning, degradation of alum to sulfuric acid, also sulfur dioxide from air pollution, etc.).

We would like to know if you could help us with the following questions:

*         Have you, or anyone you know, investigated this kind of problem of deteriorating study skins?

*         Is there a technique or treatment to rescue our skins from further degradation processes? In literature we couldn't find any recommendations for treating such old skins. Our skin collection contains over 30.000 flat skins, small mammals up to skins of giraffes, and most collected in 1900. A mass treatment method to treat many skins simultaneously would be helpful. Another huge problem in our collections is the contamination with different pesticides.

*         Do you know publications and studies about degradation processes in flat study skins? We know of Marion Kite's book (Leather and related materials, 2005), very informative and helpful, and about the STEP leather project and ENVIRONMENT project with René Larsen (1994, 1997) but other studies would also be helpful.

*         What techniques could be used to investigate the original preservation techniques? Which modern technique would be the best? Does anyone have experiences with Raman spectroscopy or XRF to evaluate original preservation methods?

*         Which easy to use, non-invasive methods should we consider using in the day-to-day business in the collections? Ideally everybody should be able to handle such techniques and fill out the elaborated profiling matrix.


Our project, to be done within 24 months, has 4 working packages:

1.       Cause analysis: finding out the causes for degradation of the skins, acid concentration, acid composition, metabolites, establish a small reference collection with skins conserved with different techniques, artificial aging etc.

2.       State analysis: profiling, in which condition is our collection, identification of possible parameters to assess every single specimen, establish a matrix for a profiling, profiling).

3.       Action plan: recommendations for the care of flat study skins of mammal collections, ideas for best practice guidelines for conservation, storage, etc..

4.       Knowledge pool and knowledge transfer: creating a free access online data base (wiki), with  detailed archive and literature references , workshops, publications, etc.
I know it's a huge program. We are currently writing the main project proposal. We are associated with two other partners: the ZFB - Zentrum für Bucherhaltung in Leipzig, Germany (a book restauration institute) investigating the mass deacidification in books and archival material;  and FILK - Forschungsinstitut für Leder und Kunststoffbahnen in Freiberg, Germany, which is a research institute of leather and plastic sheeting. We will also work together with the natural history museum in Bern, Switzerland, as in the past, they did experiences with the mass deacidification of their collection.

*         If you are interested in pursuing further discussions, we would be happy to have your input. Please contact me directly using the following contact information below.

Best regards,


Steffen Bock
M.Sc. in Biodiversity, Evolution and Ecology

Collection Management - Recent Mammals
Sammlungsentwicklung und Kompetenzzentrum Sammlung

Museum für Naturkunde
Leibniz Institute for Evolution and Biodiversity Science
Invalidenstr. 43
D-10115 Berlin
Germany

phone: +49-(0)30 2093 8506
e-mail: steffen.bock[at]mfn-berlin[dot]de

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20161128/8cd83413/attachment.html