Nitrogen Bath and Pyrogallol Developers
I am wondering if anyone here has tried using a nitrogen bath with PMK or one of the other pyrogallol developers to minimize oxidation?
I got a gas regulator and an 80 cu. ft. bottle of nitrogen for Xmas (I know, I'm a geek). I ran a 1/4 in. OD tygon tube from the regulator into the drain/pour spout of the Jobo lift so that it extended about 1 in. into the top of the Expert drum when placed on the lift. I adjusted the flow of the regulator to about a litre a minute and then did a run. I found that a development time of about 10 minutes dropped to about 7 minutes due to the longer life of the PMK when blanketed under the nitrogen.
I know that Gordon Hutchings recommends this as one of his suggestions when using the Jobo Expert drums and PMK - has anyone else here tried this?
Kirk - www.keyesphoto.com
No, it's not a burst - it just constantly bleeds the nitrogen into the mouth of the Jobo drum, which will exclude any oxygen from getting in and accelerating the oxidation of the developer.
Originally Posted by jdef
Actually, it was really easy to set up - it took longer to figure out the brass pipe fittings I needed to connect the 1/4 in. tube to the regulator than it did to do all of the rest of the set up. And the tygon tube doesn't effect the function of the Jobo lift. I thought it may keep it from getting high enough to drain the drum, but it didn't make any difference.
I can see not messing with it if you have a small darkroom, but I run the Jobo over a utility tub and not in the darkroom at this point.
I use nitrogen with PMK. At first I used liquid nitrogen as a source because I had access to it at work. I would pour a little in the Jobo (not enough to change the temp or blow me up) and it would boil out and purge, then I would cork it and shazam. Now I use bottle nitrogen gas. I don't have a regulator. I'm cheap, so I use one of those balloon filling gizmos. I forget the name, but they are about $20. I have it rigged up with a foot pedal. I put the film in the Jobo with water and put the lid on. Then I fill it all the way with water. Then I turn the Jobo upside down and blow the nitrogen in and the water out. Then I cork it. Then the Jobo goes on a base that is like a Beseler or Unicolor base. Next, I add the B-part with half the water (if the total is going to be 1 liter of developer, then I add the B-part to 500cc of water) to the Jobo and let this run for 2 minutes. Then I add the A-part with the rest of the water and start the clock. When the developer comes out of the Jobo, its color is between iced tea and bourbon, not the usual mud color without the nitrogen. The tank is turning except when I empty. The cork is in for development except when filling. This makes for even development. No streaks. Until I did this I had streaks. I passed all this on to Gordon and he thought it was fine. Got a kick out of the liquid nitrogen part. I'm doing 5x7 and 4x5 this way. Sometimes roll film, but that seems unnecessary.
Hope this makes sense. If not, I'd be happy to answer your questions. I've been doing this for 8+ years.