agitation

Discussion in 'Darkroom Developing and Printing' started by br, Sep 14, 2003.

  1. br

    br Guest

    Vigorous agitation every 15 seconds is advised when developing film with pmk
    developer. Just what does vigorous mean?

    Also there is a different look in the emulsion between 35mm and 120 roll
    film which I do not understand why ?

    I'm also concerned about development times with the new 100TMAX 120. I've
    used the times for the old T-MAX 100 for the new and the results seem to
    dull looking (no real sharpness) and not what I want at all.

    Bill
     
    br, Sep 14, 2003
    #1
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  2. Paint the outside of your blender black, fill it almost full with your
    developer, poke the film in, and turn it on. ;-)

    Actually, I do not think how vigorously you agitate matters as much as
    how consistently you agitate. I agitate continually in my Jobo, but when
    I do it by hand in SS tanks, I invert 3x avery minute. Seems enough. Of
    course I must use different times between the Jobo and the tanks to keep
    the same contrast. Not much difference, and sometimes I forget and I can
    still print the negatives with no trouble.

    Remember, some people develop their negatives in hydroquinone developer
    for hours and use no agitation. I never tried that, though. With my
    agitation techniques, developing with no agitation results in streaks
    (especially noticeable near the sprocket holes of 35 mm film).
    Well, for some films, the emulsion is different between 35mm, 120 size,
    and sheet sizes. Plus-X is a case in point. For 35mm it is medium toe.
    For sheet, it is long toe.
    If your development time is wrong, your contrast will be different, that
    is all. Sharpness is totally different. You may get the illusion of poor
    sharpness if the contrast is low. Another way of looking at it is that
    if your contrast is too high, it will appear sharper.
     
    Jean-David Beyer, Sep 14, 2003
    #2
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  3. I don't know what "vigorous" means either, its a pretty
    vague term. But, lets look at the agitation usually
    recommended for B&W developing in small invertible tanks.
    Kodak recommends agitating continuously for the first 30
    seconds and then for 4 to 5 inversions in 5 seconds at
    intervals of 30 seconds. Ilford recomends agitating at one
    minute intervals but does not specify the number of
    inversions. For Technical Pan film Kodak recommends a sort
    of cocktail shaker agitation where the tank is shaken up and
    down "vigorously" for 5 seconds every 30 seconds. Technical
    Pan, and its special developer are prone to uneven
    development when "normal" agitation is used.
    PMK, like other staining developers, depends on a certain
    rate of oxidation of the developer to give the stain.
    Probably its been found that the stain becomes excessive, or
    uneven, or that there is too much overall stain if the
    developer is not replaced at the surface of the film
    rapidly.
    The problem with overactive agitation is that it can beat
    air into the developer causing more overall stain, or it can
    result in uneven development at the edges of the film (with
    any developer) due to the increased flow there from the
    narrow passeges at the ends of the reels.
    I haven't used PMK. Some find it excellent but it does
    seem from reports here to be a rather fussy developer.
    As for the T-Max, are you asking specifically about its
    use with PMK or is this a general question. I will beg off
    its specifically about PMK. However, T-Max films are high
    resolution but visual sharpness comes from edge contrast, an
    effect called "acutance". This can be exagerated in small
    negatives by using a developer which produces what are
    called border or edge effects. This is the result of very
    localized effects at the border of a high and low density
    area. The reaction products there can cause a rise in the
    contrast of the edge compared to overall contrast of the
    negative. Such effectgs depend on the composition of the
    developer and its use. Some developers will cause exagerated
    edge effects when diluted. Rodinal is frequently used for
    this at dilutions of around 100:1. Edge effects actually
    lower resolution but this is not a significant effect for
    pictorial photography. The effect is most evident on 35mm
    film and considerably less so on 120 because of the amount
    of magnification in enlarging the negatives. That is, these
    so called acutance effects are of fixed scale. For large
    format negatives they have little or no effect.
    I suspect the dullness you complain about may be simply
    low contrast, the cure being to increase development time.
    While PMK has some virtues you might have better results
    with another developer. Because of T-Max films very hard
    emulsion the grain is not much exagerated by Rodinal. If you
    want acutance effects try a high dilution of Rodinal. For
    best overall sharpness and fine grain Xtol is probably about
    optimum.
     
    Richard Knoppow, Sep 14, 2003
    #3
  4. br

    br Guest


    I have used the cocktail shaker technique on some rolls of 35mm TMX with
    success > ( I'm positive I think)
    with enlargements up to 11x14 that looked good to me and that's whom I'm
    trying to please but I'm not very happy with TMY developed in PMK. I do have
    a package of X-TOL I'll try tonite. I have'nt had the success with X-TOL in
    the past but from reading this newsgroup I understand it's been improved.
    We'll see.

    Bill
     
    br, Sep 14, 2003
    #4
  5. Being a luddite, who is still using Rodinal and D-76 as my two developers, I
    just souped some 120 T-Max 100, negs, taken today at the local airport, in
    D-76 1:1 as that is the only 'fine grain' developer in my lab... They are
    hanging now... I have to say that while the images will never be mistaken
    for fine art they really sparkle and they should print just super at grade
    2......
    The brick of film is one that just surfaced yesterday from the back of the
    freezer with an expire date of 1996, as I was rooting around for some Velvia
    135... I had bought the T-Max with the intention of calibrating the lot,
    and giving it a real try, then got diverted... Film doesn't normally last
    that long around me but a couple of packages were piled on the brick and it
    slid past me all this time... So, I am going to get with the program and
    shoot it up before it does start losing speed or fogging...

    Denny

     
    Dennis O'Connor, Sep 15, 2003
    #5
  6. br

    br Guest

    Thank you very much for the kind advice,

    I developed an important roll, to me anyhow, using XTOL straight for 7.5 min
    at 68 deg. and got just what I wanted. Razor sharp and perfect development.
    I'll print these tomorrow morning. We had the nina, a replica of Columbus's
    ship moored here in Ludington,Mi. in our small but beautiful harbor. It was
    only here for a few days and now gone and enroute to Porta Viarta. A once in
    a lifetime shot. I'm already planning the print to be as I envisioned it.
    Toned with selenium and then soaked in tea (?) and mounted on a piece of
    driftwood.. If it works out right I may vignette it also. Lots of
    possibilities with this one.

    Thanks again group.

    Bill
     
    br, Sep 15, 2003
    #6
  7. br

    J Stafford Guest

    Were you struck by how amazingly small and crude it was? Imagine sailing
    across the ocean on it. (Sorry for the OT, folks.)
     
    J Stafford, Sep 15, 2003
    #7
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