Hi,
I've had some success using 100% cotton and cyanotype - obviously the finer
the weave, the more detail will be resolved. Its' important to wash, rinse and
dry the cotton before coating because its often sized when new.
synthetic / natural mixes didn't work as well. I haven't tried silk.
As for coating, I've had most success with ironing the material, laying it on
something flat and non absorbent like a piece of glass or laminate, and then
apply the cyanotype emulsion with a broad paintbrush, brushing very liberally
in all directions to make sure its evely saturated, and then hanging it on a
make-shift line in the dark to dry overnight. BTW, its important to keep your
fingers pff the material whether wet or (before exposure) dry. Something in the
fingers (acid?) is apt to leave stains.
Its worth while using a small off cut as a 'test strip' for exposure before
committing the whole piece. I have usually developed in a large tray with
running water, but I didnt think this was very critical. For a really intense
blue, I found that after initial development, brief immersion in a wealk bath
of pottasium dichromate and then washing gave a lovely dark shade. Whether this
affects permanency, I'm not sure.
Anyway, have fun - I did!
--Chris Read