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

Tue Nov 29 15:49:43 EST 2016

Steffen, you've probably already looked into similar research for the
deterioration of leather bindings in books. There, the condition widely
known as "red rot" produces a drastic weakening of the skin as you
describe, a byproduct of acidic tanning processes. The best product I've
used to counter its effects is sold as "cellugel". It's fairly expensive
and does not bring the leather back to its strong original condition, but
it does stabilize it fairly well. There is another product available in the
UK (shipping issues with alcohol limits is availability), here:
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.leatherconservation.org_products_sc6000_&d=CwIFaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=WN8dGR-7dZBcQ0lM16v1JVtXD8iTuflQCZUe1xNZXdk&s=6TPZvQXi83K5yGmyOs9Xic4C_rKnIjOnpX9QI89r6Zk&e= 

You might try these, or investigate other methods to introduce a
matrix-fixing and perhaps de-acidifying solution into the deteriorating
skins.

Regards, K.

On Mon, Nov 28, 2016 at 12:41 AM, Bock, Steffen <Steffen.Bock at mfn-berlin.de>
wrote:

> 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 <+49%2030%2020938506>
>
> *e-mail: steffen.bock[at]mfn-berlin[dot]de*
>
>
>
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-- 
Kevin Winker
University of Alaska Museum
907 Yukon Drive
Fairbanks, AK 99775
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