CCI2014050733

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The purposes of our Computer registration were these:

1.    to write a report on the condition of the collection for the Ethnographical Department at the National Museum of Denmark

2.    to show the degree of deterioration of the Eskimo fur and skin collection

3.    to plan our development of conservation methods

4.    to define the need for conservation.

A OOMPARATIVE INVESTIGATION OF METHODS FOR THE OONSOLID-ATION OF WET ARCHABOLOGIGAL LEATHER. APPLICATION OF FREEZE-DRYING TO POLYETHYLENE GLYCDL IMPREGNATED LEATHER

Jan Wouters, Konk. Inst. v. h. Kunstpatrimonium, Brussels

Introduction

Leather that has been in contact with water from immersion (waterlogged) or from burial in humid soil is defined for these purposes as wet leather. Vegetable tannins were amply used in fact for the fabrication of leather; they are partly water soluble and are not all tightly bound to the collagen fibers of the hide. The leaching out of vegetable tannins from the leather leaves the dermal fiber network with less protection against biological and Chemical attack. Factors such as oxygen, iron slats, and other soil contents may enhance and/or complement this detannization, so that even the protein fibers may be attacked. When such leather is unburied and left to dry at room temperaturę, it will shrink and harden and, possibly, break.

Products normally used to improve the suppleness of dry but undegraded leather (the well-known fatliguors and dress-ings) will not suffice to stabilize the chemically degraded waterlogged leather. Such leather needs support to prevent the fibers from collapsing. Moreover, the supporting materiał should help to restore a good moisture content.

Impregnation and Lyophi1ization Procedures

Most conservation treatments for waterlogged leahter can be divided into four main groups:

-    the use of polyethylene glycols up to a molecular weitght of 1500; the impregnation is eventually followed by lyophilization (freeze drying) and finishing techniąues

(1-4, references in 5).

-    other synthetic polymers, mixed with plasticizers and/or smali hygroscopic molecules, e.g., glycerine, PEG 400 (4, 6, 7).

-    application of a fatliąuor or a dressing, after thorough cleaning (8).

-    replacement of water by a less polar solvent (5).