Textiles 83
Again due to the highly crystalline nature of fibroin, degummed silks are rela-
tively resistant to damage from micro-organisms. A consequent advantage is
that proteolytic enzymes can be used in the degumming process.
4.6 Conservation Treatment of the Shackleton Ensign
The severely degraded nature of the silk, particularly the cream-white threads,
was immediately obvious on examination of the ensign. Even very careful han-
dling caused additional damage to the stiff, fragile fabric; this proved to be a
particular problem in areas of marked staining. Our analytical work had sug-
gested a reason for this, the heavy tin weighting of the cream-white silk. In
the ‘dynamite’ weighting process the fabric is immersed successively for many
hours in solutions with pH values as low as 1 and as high as 10. The immedi-
ate damage caused by this and any prior bleaching will have sensitised the
silk. Subsequent light-promoted deterioration, probably accelerated by the
suffused tin, is likely to have been responsible in main part for the catastrophic
ageing that has ensued, though other agents will have been active. Tin oxohy-
droxide, formed from the deposited tin salts, will have effected hydrolytic cleav-
age of the fibroin. There was also evidence that the deterioration of the original
wooden frame had resulted in the acidification of the adjacent textile, leading
to further damage to the underlying silk fibres.
In these circumstances, ideally, measures should be taken to stabilise such a
material, inhibiting further decay and consolidating the fragile fabric so that the
hazard of handling is mitigated. Initially the ensign was gently surface cleaned
with a low suction vacuum cleaner, to remove loose debris such as broken fibres
and dust. However, the risk to the ensign of removing ingrained soiling and
relieving acidity by more interventive approaches was considered too high.
Tests confirmed that the cloth was too frail for wet cleaning and deacidifi-
cation, i.e.soaking with a buffered weak detergent solution. Sample fibres
immersed in water became considerably swollen and soon fragmented. This
damage was exacerbated when samples were moved, as would be necessary
during cleaning, rinsing and drying. (Where exposure to water is inappropri-
ate, textiles may still be treated with an organic solvent to remove less polar
soiling. However, dimensional changes are again likely and furthermore the
solvent may serve to desiccate the fibres.)
Simple humidification, which is often used to increase the pliability of fra-
gile textiles for handling and so facilitate stitching, was also thought to be too
risky. Nonetheless, consolidation of the brittle fabric and a supporting treat-
ment was obviously necessary to preserve the integrity of the ensign, such as
it was. Consequently, a suitably dyed silk crepeline net was adhered to the
ensign with a water-dispersed butyl methacrylate adhesive. Of course, contact
between the silk and water had to be avoided, so the net was first coated with