Can anyone recommend a leak-proof table top developing tank?
Firstly I am new to Apug, so hello all.
I would be grateful for any suggestions for a table-top developing tank which can be inverted without leaking. I have been using two paterson type 4 tanks for a long while (25yrs plus) and they are now leaking badly when inverted (they never were completely leak-proof). I have recently tried the rotation method of inversion again but this has resulted in uneven development (more development closer to the edge of the film). Not sure why (developer, perhaps?), it never used to happen.
So I think it is time to get some new tanks. Any suggetions would be gratefully recieved.
My understanding is that 100% leak-proof tanks are about as common as unicorns. That said, stainless steel tanks are reputed to be a bit more resistant to leaks than plastic tanks, on average. My own SS tanks are less leaky than my plastic tanks.
The rotational method of agitation can work reliably, but some people find it tricky. You could try shooting a few test rolls and vary your rotation style (speed, intervals, etc.) to resolve this problem. FWIW, I've got an odd Russian tank that develops one roll of 120 film in 260ml of solution, but only supports rotational agitation. After a first abysmal result, I started using very vigorous and quick back-and-forth motion (perhaps 8-10 twists of about 90 degrees and then back again in 5 seconds) for my agitation cycle, and this works pretty well. After that first bad result, I posted here asking for advice, but I can't seem to find the thread. Some people got surprisingly emotional on the issue of agitation method.
Buy a new tank if yours are that old.
I think I have seen more unicorns than leak-proof tanks.
Originally Posted by srs5694
Jobo tanks are probably the most leak-resistant.
A well fitting stainless tank is next: The real Nikor/USA tanks are reasonably good; The older Kinderman tanks with the stainless can and plastic top were OK, but I have a new one that leaks like a seive; the Japanese tanks with misc. brands - Omega, Nikor/Japan, Kalt ... - are a bit of a crapshoot, some have lids that fit well, some don't.
I haven't had good luck with the plastic AP tanks.
Tanks leak much more in the fix, where gas is generated, than in the developer where gas is absorbed.
I put the tank in a plastic food bag for processing so the tank leaks into the inside of the bag and my hand stays dry.
I always thought the Paterson gasket material a bit hard for its purpose and can cause some weeping. I found that when applying the soft white cap, depress the center and when sealed, creates a slight vacuum and stops the weeping.
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I've tried the Yankee tanks, SS tanks, generic tanks and JOBO. All my tanks which tend to be older, leak to some degree. I troubleshot to the point of discovering my leaks were mainly a result of "fixer outgassing". During the developer cycle a vacuum was created in the tank, not a problem. But during the fixer cycle a pressure built up inside the tank. When I inverted the tank the pressure was enough to force the small amounts of fixer through the weaker seals. By the end of the fixer cycle my hands were covered in fixer. I finally settled on just using the JOBO tanks for their simplicity. To minimize the pressure build-up, I drilled a tiny hole (ie; .5 - 1mm) in the center of the rubber lid. This allows the pressure to be released during the fixer cycle. When I invert the tank during development, washing, and fixing, I cover the hole with one finger. When the tank is uprighted I uncover this hole. Though this doesn't fix a truely bad seal, it did relieve the frustation by about 80%.
Last edited by DannL; 03-16-2009 at 04:18 PM. Click to view previous post history.
"Lo único de lo que el mundo no se cansará nunca es de exageración." Salvador Dalí
This tank used with the central agitator rather than inversion is as close to leak proof as you will find. http://www.freestylephoto.biz/5041-A...ls?cat_id=1603
I used one regularly about 8-10 years ago agitating 5 seconds in every 30 seconds and it worked wonderfully.
Great little idea. I will have to try this.
Originally Posted by DannL
I've had fantastic luck with the stainless tanks with the plastic (PVC) lids. You have to replace the lids every so often because they get a concentric crack in them, but the tank itself will last forever. I've gone completely away from plastic tanks and reels to SS because of the leak resistance of this setup.
Paterson tanks lids are great if you 'burp' them (technical term)... ie lift up one edge while depressing the center of the plastic lid, once the middle is depressed, push the edge you lifted up back down. It will now be pretty leak proof! I do this with a System 5 tank with 3 rolls of 120 in it. Seems to work well after being 'burped'