I too have never experienced air bells in over 50 years of film processing. But then I have always followed Kodak's directions for agitation. Check their website if you have any questions.
Many manufacturers include a wetting agent in their emulsions. Presoaking removes this and can actually cause problems rather than solve them.
I have never considered stand development to be a routine development method. Pan-F Plus builds contrast very quickly and development must be carefully controlled to prevent problems with this film.
OK so I cannot match 50 years! I have never had probs in 10 years until I tried the Pan F in Ilfosol S but then again so many new variables were brought in I cannot be sure what the issue was:
Originally Posted by Gerald Koch
Different country (air, humidity etc)
Different film/dev combo
Lack of solid surface for bumping the air bells away until I discovered the body armor technique.
No prob with any other film even in the same developer! only really an issue with 120 as sprockets as bells largely form at edges only it appears.
I have a couple of those old tanks that I don't use because they just seemed brittle. The ones I have now ( about 6 years old) seem to be made of much sterner stuff. They have gotten a lot of good solid "thumps" and show no signs of cracking but I do have a piece of fairly hard rubber about 3mm thick that I use to keep from marring the darkroom counter. Dave
Originally Posted by Konical
I have a different take on what might contribute to the creation of air bells. I make an effort to reduce the amount of air dissolved (to all the chemists/physicists out there I apologize in advance if this is the wrong term) in the water I use for mixing developer. I just let it sit in jugs for several days and rap them once in a while to bring the bubbles to the top. Developer mixed from powder is always allowed to sit for a at least a few days because I hate it when I have film that I want to see right away and I have to stop and mix things up first.
I have found that tap water has a lot of dissolved air. I have seen fewer bubbles in bottles of distilled water purchased from the store, and no problem with distilled water we have delivered (but that always sits for at least 2 weeks before using).
Although I usually use a Jobo, when I do use conventional tanks I only rap the tank lightly. It really isn't necessary to bang on them. Fill a clear plastic bottle with tap water and you will see that it takes very little effort to dislodge the bubbles from the sides.
Good luck solving your problem,