I've been using PMK for decades now, and I love the results I get with HP5 and Tri-X. I don't have any problems with roll film processed in PVC tubes with a Unicolor, Uniroller; however, with sheet film (4x5 — 11x14), I often have trouble with hot edges and blotchy skies.
I started using PMK after reading Gordon's book, and have generally stayed with that technique ever since. In the case of my sheet film, I think it's pretty obvious that the problem is me — my technique. In almost all processing issues, agitation is the culprit, so I suspect the difficulty lies somewhere, somehow in the developer tray. I'm using standard tray technique, but clearly something is amiss. I'll briefly outline my methods, but what I would really appreciate is more information regarding PMK sheet film processing in open trays.
I start with a 5 minute pre-soak that includes a bit of baking soda to prevent film sticking together (I should add that I use highly filtered, untreated, hard water). I transfer the sheets, one at a time, into the tray, rarely, if ever, processing more than six sheets at one time. Once all the film is in the PMK, I shuffle the stack constantly, generating the equivalent of moderate agitation. I gently (to avoid hot edges, that I'm getting anyway) rotate the stack 90º every minute, or so. My standard time for HP5, exposed at 160º, is 14 minutes. Additionally, as per advice from this forum, I add small, measured amounts of photo grade, sodium sulfite to the standard PMK dilution. Following the developer, the entire stack is transferred into a running, plain water, stop-bath for 1 minute. Fixing is done with T-4 for 5 minutes. Obviously, however, the problems are occurring in the developer, not at any time afterward.
I know so many people who employ PMK without any issues, I know it's me, and I DON'T want to change developers. Although, I used HC-110 for twenty years without any similar problems. But after moving to PMK, I'd really like to stay where I am.
Without open sky, I don't have any problems, other than the occasional hot edge issue.
I was actually trained as a biochemist (BFA/MFA came after the BS — pun intended), so I know how to manage the purity, storage, measurement, and temperature control of chemicals. Laboratory skills aren't part of the problem.
So please, would someone give me a tutorial on agitation with PMK? I have seen the problem, and it is me!