Thank you Sandy. I find that interesting about the WinPlotter and how it gives you both readings. I was kind of under the impression that it was a completely different system, partially due to the great debate that has surfaced over the internet. I actually had never heard of BTZS until I started trying to figure this out. Even when under the impression that it was different, I was on the same page with you in that using both systems could help. In this case, the only info I can find answering the original highlight compensation question is in terms of BTZS. This gives me a starting point, and what could be a failed attempt at trying to simplify it. Either way, I'm going to give this all a go. Decreasing exposure by a stop through ASA would be the same as knocking my shadow down to a zone IV on my meter, so I'll start from there. Like I said, I'm going to use your Acros numbers as a starting point and adjust as needed. And that funny formula to convert my spot readings to SBR. Thanks all for your help, I have a good feeling that this will all work.
As for Mr. King, you especially have been informative and patient with all these questions. I am extremely grateful that you took the time to read all of this and answer back, as I'm sure the rest of us are with other questions we have.
To answer this question, I am using PMK Pyro for my film developing right now. I'm already using it at weaker than the reccommended dilution, so reducing the dilution more for compensation isn't an option.
Originally Posted by CPorter
Since I am stuck on using Pyro developers, Pyrocat HD is said to be an excellent compensation developer. Pyrocatechin itself is known to be used more for higher contrast ranges, from Adams book "The Negative", and most mentors I have asked about it. All of the information I have found on pyrocat and minimal agitation for high contrast is in terms of BTZS, so I'm trying to incorporate it into my work flow.
Summary: I'm stuck on Pyro, I can't use PMK because of dilution issues, Pyrocat is better or more acclaimed for highlight compensation, and all the info for where I could start from with Pyrocat HD is in terms of BTZS.
I may be making it more complicated, but all in all I've only used about an hour total of my life figuring this all out, and film tests aren't that complicated, just time consuming. But it's all worth it if I get the desireable results in my eyes.
For anyone reading I have some follow up for this thread that I started. Here it goes.
Did some testing using Sandy's numbers. For anything less than a N-3 development (7 stops range and up) for our spot meter/Zone system users, I have seen this come in handy. I didn't use a densitometer to test densities as I don't have one that can read pyro negs, it was just through printing at a grade 2 and seeing how they looked. So for those who are into the intense testing and using a densitometer, be wary.
The steps are:
1. I usually expose my shadows to a Zone III. For the compensation, I expose them to IV. So I guess if you already use a Zone IV, then shoot them at V. I also develop my highlights to a VII, so if you go for VIII then adjust accordingly.
2. Pyrocat HD in Glycol for Formulary, 1:1:100 at 70 degrees.
Using the funky (7(D-N))/D formula for spot meters, a 7 Zone spread comes out to a SBR of 10. This means an N-3 would be 9 minutes according to Sandy's numbers. Reduce this by 20%, and you get your N-4 number, aka 8 stop range, aka about 7min 15 sec.
Agitate for the first min vigorusly, then when 5 min 30 sec are remianing for 10 secs, then when 3 min 45 sec are remaining, then when 2 min are remaining. Fill and drain tank twice for stop, fix for 5 min in Kodak rapid fix without the hardener added(solution B), and then a 20 minutes wash. They came out great. Thanks to all for your responses, and I hope this can help someone. This method came in very handy hiking through Sequoia and Kings Canyon National Parks in the middle of this month (March) with lots of snow. 60 degree weather and two or three feet of snow means bright contrasty days. And theres nothing more nerve racking to a photographer than having a contrasty day and not knowing what to do. Well, almost nothing...
Last edited by degodan9; 03-26-2009 at 03:28 AM. Click to view previous post history.
Reason: typos eveyrwhere (ha ha)