U of S | Mailing List Archive | alt-photo-process-l | Re: Seeking Information on 2 problems with Gum process

Re: Seeking Information on 2 problems with Gum process

Keith,

Would you know how permanent this method leaves the image? Would the reduction continue, or could it be arrested by reapplying acid to it? The acid would make it slightly a different blue in some cases by the way.

It's a very useful way to control cyanotype density if indeed it is permanent.

Sam Wang


On Apr 30, 2008, at 9:29 AM, Keith Gerling wrote:

As my well-water is somewhat alkaline, the cyanotype layer bleaches
out slightly during the subsequent gum stages.  My approach is to
overprint the cyano layer to the point where it is much too dark, and
then to bleach it back to where I want it when the gum is finished.  I
use dilute ammonia.



On Wed, Apr 30, 2008 at 5:50 AM, cadunn <cadunn@vt2000.com> wrote:

Henry wrote:
but I found it much better to dilute
the coating solution with anything up to six or seven times its own volume
with water. You can hardly see it as you coat it, but the blue is there OK
and you can give it full exposure. Dilute solutions seem to need rather
less

exposure than full-strength ones.

lol, Henry -- your msg. came JUST after I had coated the paper and was
planning on a much reduced exposure time, which is all at this point in my
learning curve that I knew to do --

So, next iteration of cyanotype stage variation belongs to you!

Thanks