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View Full Version : PMK Pyro streaks in Jobo - Pyrocat-HD/Rollo solution ?



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frotog
02-15-2010, 11:20 PM
Ok - whew, depending on the drum that's a lot of distilled water :o - the room I load film in isn't of the wet variety unfortunately ...

Reverse engineering your solution doesn't give me any clues as to the action of the issue itself though - ok, so now the film is wet, but how much or less 'wet' than an initial pre-wet via the usual method of less un-distilled water and a bit of agitation ... (?)
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The technique of loading the film into a jobo already filled with the water/sodium metaborate prewash has been passed on here and on other forums. It seemed odd to me that this would solve the problem but then I tried it and it worked. One would have to deduce that in loading the film dry the prewash doesn't fully saturate that part of the sheet that's pressed up against the ridge of the jobo's cylinder and discrete areas of greater or lesser stain ensue. But your problem might just be the result of excessive oxidation. If the prewash technique seems like a PITA (and it is) why not first rule out oxidation by either displacing oxygen with gas or use more solution and a cork. Good luck - it took me a long time to rid my process of the gremlins you've encountered.

outwest
02-16-2010, 10:17 AM
The addition of the EDTA solution to PMK that Gordon recommends eliminates the oxidation problem. Probably not that anyway, as the worst blotching I had was with MaxPyro. I think it has more to do with insufficient prewetting and some vagaries of agitation. The Expert tanks seem to take care of it for me.

nick mulder
02-16-2010, 03:14 PM
The addition of the EDTA solution to PMK that Gordon recommends eliminates the oxidation problem. Probably not that anyway, as the worst blotching I had was with MaxPyro. I think it has more to do with insufficient prewetting and some vagaries of agitation. The Expert tanks seem to take care of it for me.

Ridge 'blotching' ?

I'm really trying to determine if what I'm talking about is the one and the same issue with the more 'standard' pyro/rotary issues... (which in true odd pyro manner I am yet to experience)

outwest
02-16-2010, 07:00 PM
Yes, from the ridges, or even the bumps on the old celluloid film holders for 2500 series tanks.

nick mulder
02-16-2010, 07:07 PM
Ok - cool - thanks... Just trying to make sure we're all on the same page :)

I'll be up and running soon once the E6 excitement dies down and I'll report back the test results ...

nick mulder
02-25-2010, 01:53 AM
Efke 11x14" and Arista Edu 200 8x10", PMK+EDTA, pre-wet tubes, occasional lateral agitation, increased amount of chems...

Base side streaks - cant be seen on either of the negs, but bang there they are in the prints

I'm back to trays at midnight until I can try some Pyrocat-HD