Sudsing in film development?

Dante_Stella

Rex canum cattorumque
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I have had this problem for 20 years - so I guess it's time to ask. When I open the lid of a developing tank to "burp" it after initial agitation, the tank spits out copious amounts of what looks like soap suds (without regard to what developer is in use).

I've eliminated the possibility of leaving Perma-Wash or Photo-Flo on reels or in the tank - so what gives? Does 120 film have a surfactant coating that promotes wetting and causes this? It only really happens in the developing stage.

Fortunately, this has not caused marks on the film, but it sure makes a mess, especially with Rodinal - where huge amounts of purple-Kool-Aid-looking developer (+film antihalo dye) come out with the bubbles.
 
Dante, I have the same problem. It seems to be somewhat related to which film I use too. Delta 100 makes it look like a volcano erupting! Kodak's film tend to do it less. Rodinal/D 76 will do it, whilst HC 110 and various split developers does it less. I had the lid pop of a 5 reel tank with Delta 100 once! I did check our water supply and it is quite soft and that can be the culprit.
The Paterson reels have a tendency to "store" Photo-Flo and cause it too.
 
I always pre-soak film for few minutes before developing; after that, opening the lid, I care to precautionary depressurize the tank of any possible solution-waggle gas. So far, I haven't found any suds. I mostly use Rodinal and I rinse my Paterson reels just in very hot water.
 
I don't "burp" the tank after initial agitation, but I do expel all the air I can after filling the tank and fitting the cap, by pressing down in the centre of the cap while lifting the edge at one point, letting the air out, then sealing the cap again all around. With this technique I don't get any leakage as a slight negative pressure is formed inside the tank.
 
I tried pre-washing and it did not significantly reduce the "foaming". I even asked at Ilford in London once and they professed never to have heard about this problem. I suspect that the water quality has something to do with it
When we lived in Paris, which has "hard" water - I never had the problem. Biggest problem there was to keep calcium deposits from forming on the film (OK, also to keep the cockroaches from getting into the 5 reel Paterson tanks when you were loading. Nothing seemed to affect them, D76 or Rodinal, they just climbed back out with a "Oh, that was refreshing" comment).
 
I've never had a hint of this problem and it's the first time I've heard of it. FWIW, we have hard water here in Kansas City. I regularly use HP5+ and Delta 3200 in 35mm and 120, with both HC-110 and Xtol, no presoak. They're developed in stainless tanks. I agitate fairly gently, about four turns in ten seconds. I haven't even seen the slightest bubbles or foam.

*Edit* I used to use distilled water and never encountered this. Maybe trying it with distilled water can eliminate water as the culprit.
 
Suds

Suds

I don't "burp" the tank after initial agitation, but I do expel all the air I can after filling the tank and fitting the cap, by pressing down in the centre of the cap while lifting the edge at one point, letting the air out, then sealing the cap again all around. With this technique I don't get any leakage as a slight negative pressure is formed inside the tank.

I concur. I've observed the phenomenon you mention, especially with Delta but I use exactly the same method as Chris and have never had a problem. I presume you are observing the capacity recommended for the tank? Some people just "fill to the top" and in that case the problem (it really isn't a problem though) will appear worse.
 
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