pyro developed negs for cyanotype?

Hi all,

I have a question about negatives developed in Pyro. I taught a
cyanotype workshop yesterday, and while it all went well, there was a
man in the class who brought, what appeared to be, some of the most
beautiful 4x5 negatives I've ever seen. In fact, I thought they would
have been perfect for platinum printing. We had light boxes, and
people also used the sun. But when he tried to print these gorgeous
negatives, the exposure time (in the light box) was stretching an hour
or more..and still, he was losing so much, especially in the highlight
area, and basically getting faint, washed-out images. He tried
exposing for nearly 2 hours, and he just wasn't getting anything. We
tried various options, with coating, with different papers..but these
negatives, though "perfect" by my estimation (and not bullet-proof in
appearance), were just impossible for making a decent cyanotype. He
then told me, towards the end, that he had developed these in Pyro. I
thought Pyro was great for platinum..and would have thought okay for
cyantype. Haven't I read that before? But not so in this case.
That's the only explanation I could think of (the Pyro stain). Can
anybody tell me if this was the problem, and if so, why don't Pyro
developed negatives work for cyanotype?

If this has been discussed innumerable times before...I apologize...but
  thanks for any help.

Diana
Received on Sun Oct 31 12:10:59 2004