<< I have never understood the hooha about no metal, since I have never yet
heard of a platinum printer immersing a brush in platinum emulsion up to
the ferrule, unless >>
Judy, although you may only immerse the brush to this level, capillary
action will ensure that the solution creeps up to the ferrule.
As well as the use of glue (or varnish?) as you suggest, it can help to soak
the brush in purified water first, then remove most of this using absorbent
paper such as kitchen roll.
Peter Marshall
On Fixing Shadows, Dragonfire and elsewhere:
http://faraday.clas.virginia.edu/~ds8s/
Family Pictures & Gay Pride: http://www.dragonfire.net/~gallery/
and: http://www.speltlib.demon.co.uk/