Re: cyanotype question

On Fri, 3 Sep 2004, Sam Wang wrote:
>
> Delayed development does indeed alter the tonal relationship, sometimes
> quite a bit. I have used this method to help tame papers that were too
> contrasty otherwise - by delaying as long as 24 hours. Judy mentioned
> that delaying just 15 minutes (or was it 30?) would make a difference.

It was 15 minutes... but let me describe what I found, which may not be
what is under current discussion which I freely admit I do not understand.
(True, I am not certain that I couldn't understand it if I really tried,
but on the other hand I am not certain that I could.)

I was making test prints in cyanotype of a negative with a small figure in
a larger scene. On maybe the 3rd print I noticed that I got detail in
the face that hadn't appeared before. Being younger then and able to
remember things, I remembered that that particular print had been delayed
getting into the wash water because of a backup at the sink.

So I did a series of tests using a 21-step. For that particular emulsion,
on that paper, at the prevailing RH, etc. the optimum delay for improved
separation of dark tones turned out to be 15 minutes. With a longer delay
there was a loss of tone both top and bottom.

If the current discussion is about increasing the range, I didn't find
that. However, depending on paper and the vicissitudes of the will of
molecules, my students found that keeping coated paper from 5 days to one
month BEFORE exposing could significantly increase *range*. This was so
variable however as not to invite further study. (And in any event it
didn't seem necessary as an equal increase is possible by choice of paper
and double coating-- and there are so many other games to play.)

Judy
Received on Sun Sep 5 08:32:01 2004