Quote Originally Posted by palewin View Post
Also, one of the reasons for developing Pyrocat was the known oxidation problems of PMK in rotary processing, which is not recommended. )
This is true, However, you can use PMK in a rotary processor quite successfully with a couple of changes to the process - I process FP4+ in a Jobo 1521 tank with the 1509N reel all the time. I have had to make 2 adjustments to get this to work consistently.
First, use a lot of developer - for me a minimum of 500ml - this is the most I can put in my tank. Second, break up the development time into more than one batch - For example, if my development time is 10 minutes, I'll mix up 2 500ml batches of PMK, start the development with the first one, then after 5 minutes, dump that one out and put in the second batch for the remainder of the time - I find that at 70 deg F, I get the best results if I don't let a batch go for more than 5 -5 1/2 minutes.
Finally, - I add a very small amount of EDTA to promote even development - this is actually specific to my particular tank and reel - people using the expert probably drums don't need to do this - I got this info from the latest edition of "The Book of Pyro"
I also don't use the after-bath. It's interesting that even though Gordon no longer recommends the after-bath, it's still in the latest edition of his book.
I also don't see a lot of general stain on my negatives. In fact, when I got some Pyrocat-HD, I went out and shot multiple negatives of the same subject, then developed some in PMK and some in Pyrocat-HD. When I compare the negatives visually, my PMK negatives don't appear to have any more general stain than the Pyrocat negatives do - of course since I don't have a densitometer and I don't do alternative processes, it is entirely possible that there is more general stain, but I just don't see it visually or when I'm printing.