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  1. #41
    Ian Grant's Avatar
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    You can get these air bubbles happen with distilled water too, so a pre-soak isn't necessarily the answer. Agfa recommended not using a pre-soak for this reason 100 years ago

    Ian

  2. #42

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    I literally *slam* my tank down on the floor pretty hard several times. Somebody's probably going to tell me that it's not a good thing to do, but I do it because I used to get clear spots on my film.

    I'm not a pre-soak proponent.

  3. #43
    clayne's Avatar
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    This slamming and pounding that some people are doing all seems like overkill. I rap it against a towel covered surface a few initial times after filling it to the brim (stainless tank of course). Never had a single problem with air bubbles.
    Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.

    http://www.flickr.com/kediwah

  4. #44
    Rolleiflexible's Avatar
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    Quote Originally Posted by clayne View Post
    This slamming and pounding that some people are doing all seems like overkill. I rap it against a towel covered surface a few initial times after filling it to the brim (stainless tank of course). Never had a single problem with air bubbles.
    It was a gradual escalation, from
    loving taps to sharper raps to
    hammering nails. Throughout,
    the bubbles persist.

  5. #45
    Martin Aislabie's Avatar
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    Quote Originally Posted by clayne View Post
    This slamming and pounding that some people are doing all seems like overkill. I rap it against a towel covered surface a few initial times after filling it to the brim (stainless tank of course). Never had a single problem with air bubbles.
    Quiet how much GBH you need to apply to your tank to displace the air bubbles varies enormously and is dependant upon a number of factors

    Clearly it varies with both Developer and water quality.

    If you only need to tap gently – then you are lucky

    I have to tap and wiggle/shake my tank quite hard.

    Ian G needs to resort to adding tiny amounts of wetting agent.

    We are all trying to achieve the same thing (no air bubbles) – but what we have to do to get there varies considerably (YMMV!)

    Martin

  6. #46

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    When I remember I hold the top and bottom of the tank in each hand and take the bottom hand in a circular path, simplest to try it one handed with coffee in a cup over a sink, to stir in the sugar.

    But then I never get air bubbles, lots of dust, insects etc. yes, no bubbles... soft water wets better.

    Noel

  7. #47
    Ian Grant's Avatar
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    Visual tests

    Quote Originally Posted by Martin Aislabie View Post
    Ian G needs to resort to adding tiny amounts of wetting agent.

    We are all trying to achieve the same thing (no air bubbles) – but what we have to do to get there varies considerably (YMMV!)

    Martin
    Unlike the rest of you I've done some practical experiments with a tank, reels etc, taking the lid off to see what happened, in fact a few times - first with plain water and no film and once I thought I'd solved the problem then again with some old film & dev.

    Having had a Paterson tank with 7 rolls of film split when giving it a tap I don't advocate sharp taps

    Here's a few things I found last year:

    1. No amount of tapping removed air bubbles totally, although in some cases it ma be enough for then not show.
    2. Nor did inversion agitation.
    3. If you have the Paterson twist stick to agitate by turning the spirals that helps.

    4. Two drops of Wetting agent entirely solved the problem, with the surface tension broken air bubbles disappeared completely and didn't reform.

    Then some comments.

    5. Developers and films vary some developer/film combinations may be more prone to air bubbles than others.

    6. Water supplies are very variable, this will make a significant difference..

    7. The main conclusions are that some developers may contain too little sequestering agents for certain water supplies, and in most cases when you mix up yourself from scratch won't necessarily contain any sequestering agent.

    In my case using Pyrocat HD there's no sequestering agent but wetting agent has proved sufficient even with the very high salt/calcium levels of my local water supply. In the 16 months since changing my way of working I've had no air bubble marks on negative.

    My suggestion to anyone having persistent problems is do some visual tests with your tank and some dry spirals, you'll find it can be hard enough to dislodge the air bubbles with no film loaded, it's even worse with a film in the spiral.

    If you do this you should find what will works best for you.

    Ian

  8. #48
    Martin Aislabie's Avatar
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    Quote Originally Posted by Ian Grant View Post
    Unlike the rest of you I've done some practical experiments with a tank, reels etc, taking the lid off to see what happened, in fact a few times - first with plain water and no film and once I thought I'd solved the problem then again with some old film & dev.

    Ian
    I too have done this, firstly with plain water plus empty reels and repeated with Dev and sacrificial Film

    Its alarming just how persistent and tenacious the air bubbles can be :o

    As Ian says, everyone should try it

    My standard Dev is ID11, which has enough wetting properties to assist in the task of dislodging the bubbles.

    I have always steered clear of Pyro Devs because they seem to lack the wetting ability of the main stream devs like ID11/D76

    However, I am still curious how the air bells seem to seek out and randomly attach themselves to some of my best negs

    Martin

  9. #49

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    i never knew there was a special and significant
    technique to rap the container to get the bubbles off ..
    other than just hitting the tank on the side or bottom of the sink ...
    this thread has been quite a read, thanks!
    silver magnets, trickle tanks sold
    artwork often times sold for charity
    PM me for details

  10. #50
    Ian Grant's Avatar
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    It's also worth mentioning that often water supplies can vary in some areas.

    In the UK my local water comes from two sources, either the very soft Birmingham Welsh water from the Elan Valley reservoirs or local boreholes which is very hard, it can also be a mix of the two.

    Here in Turkey it's again from reservoirs but quite hard water, but when they dry up or run low in the summer we switch to a borehole and that water has a far higher salt/calcium level as we are very close to the sea. Either way none of it is drinkable

    So when people get intermittent problems it may be their water supply was switched for a short time.

    Ian

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