Polyester resins

Simon Moore <simon.moore [at] hants__gov__uk>

>This is rather an old chestnut I fear but no-one seems to have an
>answer as yet. I am embedding all sorts of biological specimens in
>polyester resin which uses styrene as its main solvent.  As many of
>us know, aromatic-methyl solvents (eg xylene) are excellent
>microscopic clearing agents.  I need something to spray,
>particularly on lepidopteran wings, to prevent this transparency in
>the resin.  Blue butterfly and Morpho wings lose all their
>iridescence.

I was always under the impression that the colour/iridescence of
insect parts is a physical colour not a chemical colour. That is to
say the colour is about the microscopic scales on the wing surface
and the way light refracts off the surface in a physical way. As
opposed to chemical colour which is in the pigment of the cell
growth. i.e. fur. I can't see how applying anything to the surface
of an insect wing isn't going to disrupt the physical colour and
ultimately change the light refraction and reflection off the
surface. In fact even if you find a coating still allows the light
through I think the problem is the refractive index of your resin.

Victoria Gill
Textiles Conservator


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                  Conservation DistList Instance 18:27
                Distributed: Thursday, December 16, 2004
                       Message Id: cdl-18-27-008
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