Stand dev: Air bells, all films equal?

Discussion in 'B&W: Film, Paper, Chemistry' started by MMfoto, Dec 10, 2006.

  1. MMfoto

    MMfoto Member

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    I've recently entered into the exciting realm of stand and semi-stand development. I've been using the Formulary's TFX-2 version of FX-2 at twice the normal dilution. My first attempt was with Pan F+ which gave me tantilizing if very high contrast negatives. My latest go has been with Acros. The resulting negatives are inspiring and the density range looks about perfect. They are also rediculously sharp.

    The only problem is, I've just had my first ever run in with air bells! Little low density spot appearing in the sky region on about every other frame.

    My agitation sceme was 60sec intial and 60sec at the 30 min mark, followed by an hour of full stand. I did NOT presoak. I certainly will next time, but my question is:

    Are some films more prone to air bells than others?

    I remember hearing at some point that Ilford doesn't recommend presoaking their films as they apply a wetting agent to the emulsion. My Pan F+ negs came out fine and the Acos negs were littered with air bells, both with equal development technique...
     
  2. Steve Sherman

    Steve Sherman Subscriber

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    There seem to me to be so many positives why film should go through a Pre Soak and so few why nots, for me it doesn't even merit a discussion. Pre soak each and every film you use.

    Air bells can be a result of surface tension also, in the winter months obviously the air is dryer and more static can be created, hence surface tension. Therefore, I would always presoak and my initial agitation would always be vigorous in nature. These two steps should yield terrific results

    Lastly, to a fault remain constant with the technique you use each and everytime.

    Cheers!
     
  3. karavelov

    karavelov Member

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    I have also noted that some films attach more bubbles than others. I didn't knew that presoak is not recommended for some films.My experience is that the more sensitive films (ISO 400) attach more air bubbles. It is more evident in medium format where the image goes 2 mm to the edge of the film.

    Does adding a little photo-flo to the developer will help ?
     
  4. zenrhino

    zenrhino Member

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    Maybe a good thwack on the countertop as you set the down the tank will shake loose those air bubbles.
     
  5. mongo141

    mongo141 Member

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    Just what I do, I dump in the developer and give the tank ( in this case Patterson Tanks) a couple of good solid thumps on the table and start the agitation schedule. If I forget I sometimes end up with air bell's and they seem to occure almost anywhere on the negative (always on the negative I really want). Doesn't seem to matter what film it is from the cheapest to the most expensive, Just happens. Dave
     
  6. jim appleyard

    jim appleyard Member

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    That's what I was always taught from day one. I honestly don't recall ever having an air bubble problem.
     
  7. reellis67

    reellis67 Subscriber

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    For what it's worth, I've never seen problems with air bells with either 'regular' or stand development. With stand development I've always done a 2 minute pre-soak, even with Ilford films, but I don't do this with 'regular' development. I do however rap the tank after agitation each time just to be sure no matter what type of development I'm using.

    - Randy
     
  8. Tom Hoskinson

    Tom Hoskinson Member

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    I always presoak with tempered water for each type of agitation that I use: (continuous, minimal, semi-stand and stand agitation). I do not have airbells. I never add photo-flo to my developer. I frequently use Kodak TRi-X - 320, Kodak TMAX 400 and J&C Classic Pan 400.
     
  9. Konical

    Konical Subscriber

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    Good Evening, Dave,

    ". . .give the tank ( in this case Patterson Tanks) a couple of good solid thumps on the table . . ."

    Decades ago, I also had this habit with Paterson tanks; the habit ended when my tank cracked. It was awkward to hold it tightly together throughout the rest of the processing steps! The tank was quickly repaired with solvent cement, of course, but the experience was enough to convince me to go SS. The Paterson equipment has been sitting on the shelf ever since.

    Konical
     
  10. Tom Stanworth

    Tom Stanworth Member

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    whacks on a surface do not need to be that hard if the surface is hard enough. This is why I used to use my kitchen floor (on concrete). If the surface is not hard you can really abuse the tank and the air bells stay put! If you sticke it with the base parallel to the surface damage is highly unlikely. I dont have a solid floor in Kabul (and people sleep shifts nearby!!!), so I use by body armor plates now :smile: works a treat. I found Pan F to be a major pain with Ilfosol S when it comes to air bells. Just could not get rid of them entirely so wont use this combo again.
     
  11. Gerald Koch

    Gerald Koch Member

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    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.
     
  12. Tom Stanworth

    Tom Stanworth Member

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    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:

    Different country (air, humidity etc)
    Different water
    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.
     
  13. mongo141

    mongo141 Member

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    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
     
  14. Neal

    Neal Subscriber

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    Dear MMfoto,

    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,

    Neal Wydra