>On Tue, 10 Sep 1996, Terry King wrote:
>> If platinum solutions soak through the hairs to the ' iron' ferule the
>> sensitiser becomes contaminated with iron and prints become muddy and grey.
With
>> gum the dichromate speeds up the rusting of the ferule so you get bits in
your
>> picture.
>My point was that I've never seen this happen, that is, I've never seen
>.emulsion of any kind go more than a short way up the bristles.
I have seen both happen and that is why I recommend non metal ferules. As to
brushes or applicators or glass rods their effectiveness differs from paper to
paper and from process to process. I now do nearly all my coating with of
gum,acrylics, cyanotypes,kallitypes, platinum, gold,salt and silver sensitiser,
a different brush for each process, with 'hake' brushes bought from the Guang
Hua Trading Company in Newport Place behind the Charing Cross Road. They are
downstairs on the right at the end . My posh sables and ox hair and lacquer
brushes and applicators and glass rods sit as museum pieces in their draw. The
gum brushes I wash with water and the others with purified water and EDTA.
Terry