U of S | Mailing List Archive | alt-photo-process-l | pyro and cyano

pyro and cyano

  • To: Alt List <alt-photo-process-l@usask.ca>
  • Subject: pyro and cyano
  • From: "Christina Z. Anderson" <zphoto@montana.net>
  • Date: Tue, 07 Apr 2009 23:12:12 -0600
  • Comments: "alt-photo-process mailing list"
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I printed a side by side pyro neg, regular neg and step tablet on Cot 320 paper. The good news--the pyro neg did print; it wasn't a square of white. The bad news, it looks like a 12 minute exposure is best (a little lighter than a very dense regularly developed neg printed at the same time) when the actual standard printing time on that paper with 1A:1B traditional is 6 minutes. Thus I would wager a bet that the pyro negs if NOT run through an afterbath of spent developer is going to be in the order of 1 or more stops more exposure than a non-pyro negative. But none of my tests showed pure white squares of nothing and thus I am wondering if there is something further wrong with your light set up. I guess I can't know unless I printed one of your negs.

OH, and the contrast is a little excessive for cyanotype as well. I get 6 stops on my cyano-printed step wedge, but the shadows are blocked up on the pyro print before the highlights are fully printed. Which stands to reason why pt/pd printers LOVE pyro but why it might be difficult for cyanotype unless the range of the negative is more compressed. So....hopefully some of this helps.

Christina Z. Anderson