Thanks to all those who have responded to my request for advice on wet
cleaning and fractured/cracked/crazed blue beads that are stitched to a
Berlin Work embroidery.
The use of cycldodecane is an interesting possibility but there seems
to be (at least?) one disadvantage and that is that the canvas will
also be impregnated, otherwise the beads could not be fully coated on
the underside where they are in contact with the canvas.
I find it more clarifying to think things out by writing, so I might as
well share the process and enjoy the synergy of your responses as a
bonus. Please bear with me.
Closer examination, has revealed that the cotton canvas under the
beads and the securing threads are white while the rest is "aged" light
brown. The white fibres are strong, perhaps stronger than the rest of
the canvas. The pH, measured with a 0-14 pH indicator strip, is about
8.5. It would appear that the beads have had provided an alkaline
reserve for the cotton! The pH may or may not rise with time. There is
no surface efflorescence on the beads. I would prefer to be able to wet
clean it to lower the pH even though this would probably only be a
temporary respite. However, the cycldodecane will no doubt prevent
this. (No, I do not intend to try to lift and rotate each bead to coat
it inside and out using a tiny brush).
At this point, I see two possibilities:
1 just wet clean and hope that not too many beads will shatter -> loss
of (some?) beads, saving of canvas (some beads were wet during the pH
measurement but did not break - hopeful)
2 apply cycldodecane and hope that the pH will not continue to rise in
time -> loss of canvas -> loss of beads (Postponing the problem? How
likely is this scenario?)
Ad 2 future loss of beads due to loss of canvas could be prevented by
securing them to a support layer with a polyester thread. Should the
canvas and thread rot away, the beads will remain in their original
position. But I am sure that the handling involved, especially trying
to pass a needle and thread through these quite small beads (next to
the original thread or not) would also cause breakage. This is not a
good idea.
I'll leave it there for now. Responses are very welcome.
Another article on the subject is "Deterioration of beads on an
Edwardian evening bodice", Annie Lord, in Ethnographic beadwork:
aspects of manufacture, use and conservation, Archetype Publications,
2001
PS
Since this sudden immersion in the stability problems of glass beads in
connection with textiles, it seems as though the development of the
problems is fairly recent or is it just the awareness that is recent? I
am curious to know if it is a phenomena which needs time to develop and
become noticable, as was the case with celluloid which seemed to
disintegrate simultaneously over the whole world in the 80's and 90's.
If it is a recent general development and not just isolated cases, then
it would seem to be a urgent subject for research and funding in order
to save late 19th century and early 20th century beaded costume and
ethnographic textiles. The problem provides a variety of good subjects
for students looking for a final project!
Jennifer Barnett
historical textiles research & consultation
Oude Looiersstraat 65-67
1016 VH Amsterdam
Netherlands
tel/fax ** 31 (0)20 427 18 27
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