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Thread: Agitation

  1. #11

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    If I get frothy developer I admonish myself severely for not rinsing all of the photo-flow out of the tank and reels after the last session

    I don't like twiddling tanks - I don't think the developer gets moved around enough. I don't worry about the film coming momentarily out of the developer when I invert the tank - the emulsion is saturated with developer - it won't dry out in such a short time.

    Five inversions in every 30secs seems a bit much to me...
    Users of Kodak film tend to agitate every 30 secs because that is what the instructions said. Same with Agfa.

    Ilford have always recommended agitation every 60 seconds, which is what I use, and I only give a couple of inversion, twisting the tank as I do so. I give 5 inversions when I first pour the developer in, though, then a good tap on the bench to dislodge air bubbles.

    Consistency is everything - you learn the timing and rhythm like a dance move or something (just had a great idea for a youtube video, anyone up for showing off their 'technique'?) but I don't think the exact number of inversions or times are that important. They do make a difference, but as long as you are consistent then you can adjust your developing time to suit. I've developed plenty of Kodak films in Agfa developer and used Ilford's 60s agitation and it works perfectly well.
    Steve

  2. #12

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    Catch up post

    I implied that Rotary processing 'smoothed 'grain , and improved sharpness and acutance.
    I meant : the smoothing of the grain Reduced the above.

  3. #13

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    I'm with Michael W.!

    Jeff

  4. #14

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    Quote Originally Posted by cornflower2 View Post
    If a neg is really important, continuous agitation is the fastest, finest, most reliable way to go, always. Hope this helps!
    Continuous agitation can produce its own set of problems such as surge marks. AFAIK, this method has never been recommended by any of the major film manufacturers such as Kodak. Developers such as Acufine will not produce good results unless their agitation scheme is followed closely.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #15

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    Quote Originally Posted by lacavol View Post
    If I invert (which I did) then the film is out of the developer for a bit of time depending on how fast my inversion is.
    Don't worry about that. The film still develops because of the developer inside it. The purpose of agitation is to ensure that fresh developer is available at the surface most of the time so that solution interchange brings fresh developer in and exhausted developer out. That interchange is not very fast but it is important.

    Quote Originally Posted by lacavol View Post
    I have a Patterson tank so I could use the twisting method, which I haven't tried yet. It seems to take me about 15 seconds to do 5 inversions, otherwise it seems as though I'm making a drink, which would seem to froth the developer.
    That's way too much agitation. That's why your negatives are a bit dark. Agitate for five seconds every 30 or every minute, your choice. I chose 5/30 for D-76 1:1 and TMax; mostly because I've always developed film that way. Only in the first 30 seconds after all the developer is in do I agitate continuously but gently to ensure that all the bubbles move around so that all the surface is uniformly in contact with solution.

    The purpose of agitation is not to have a specific number of inversions, but to have a specific amount of time where the solution is in motion. You really don't need much, just enough to ensure that fresh solution is available at the surface.

    If that means only two gentle inversions in the 5 seconds, so be it. I do 2 inversions and a gentle tap or rap as I set it down.

    Quote Originally Posted by lacavol View Post
    Does the twisting method work? Should I be doing inversions faster? Do I need a metronome, otherwise how do I know if I'm agitating the same or differently on different days?
    Twisting is fine. Don't do the inversions faster, do fewer so that you only take four, five or six seconds.

    Whatever method you settle on, be consistent in the long run. Consistency is more important than one specific setting or another of any given parameter. Especially keep the temperature consistent, within one degree C for the entire development (stop and fixing can be within a few degrees) and the same temperature and tolerance each time. I find it easy to keep the temperature of a water bath in a tub within a quarter degree C for a ten minute development if it is close to room temperature.

    Quote Originally Posted by lacavol View Post
    Thanks for all of the replys and I welcome more. It seems it is more an art than a science with consistancy as the key. I'll try to use all of the advice to get a consistant routine. I used 20° C as my thermometer has a arrow there, of course it could be inaccurate.
    You got it about consistency. Don't worry if the thermometer is off, just so long as you always use the same thermometer and same temp. More accurate thermometer better than less accurate, but consistency is the key, as you now know. If you change thermometers, calibrate the old one versus the new one and it will guide you on changing your time or temperature for the first few runs with a new thermometer.

  6. #16
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    Thanks everyone, I shot a few rolls and developed them. I think that inversions for the first 30 sec. and then 4 inversions in 10 sec. every minute worked the best for my film and developer.

    Just one question which I haven't tried yet... wouldn't a diluted developer and longer developing time make any timing errors smaller in relation to developing time?

  7. #17

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    Quote Originally Posted by lacavol View Post
    wouldn't a diluted developer and longer developing time make any timing errors smaller in relation to developing time?
    Correct. That is the reason that Kodak strongly urges not using times less than 5 minutes for manual development. However, if you are safely beyond five minutes, then the other effects of dilution become more important (acutance, grain, ...).

  8. #18
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    Indeed, the best practice is to be consistent. Take errors associated with agitation out of the equation by doing it as reproducibly as you can.... then you can begin tuning your recipe in terms of time and tempt etc. to get the results that you want.

    For me, agitation has always been a few sharp initial raps on the tank (or just banging the tank on the table) to dislodge any bubbles, and then a smooth inversion, and then 10 sec of gentle agitation (rocking) in every minute, with one more inversion half way through. I simply try to randomize the motion of the fluid while also not creating froth. I don't think I've ever once had the slightest hint of irregular development.

    Quote Originally Posted by lacavol View Post
    Just one question which I haven't tried yet... wouldn't a diluted developer and longer developing time make any timing errors smaller in relation to developing time?
    Well... just for general interest, there is something very different from dilute developer / long time approach that you might like to read about, namely monobath developers. So named because they contain the developing and fixing potions in the same single bath. The development occurs very quickly and so all you do is agitate well and whistle a tune and you're pretty much done... with developing and fixing. Timing is not critical at all, and neither is agitation. Plus, fixing basically occurs automatically right after development. If this interests you then search on APUG for more info. Guided by the book by Haist, I have experimented with monobaths.

    Notwithstanding the initial mixing of chems, I find monobath to be very easy, and at least for larger formats it yields very good results. I wouldn't recommend it for 35mm though.

    Enjoy experimenting!
    "Only dead fish follow the stream"

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