Significant Pullig - Effects?

Discussion in 'B&W: Film, Paper, Chemistry' started by Athiril, Apr 15, 2009.

  1. Athiril

    Athiril Subscriber

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    I have a bunch of ISO/ASA 100 (Shanghai GP3) in the fridge I'd like to mess around with on my RB67. (I have no slow speed film atm at home - and I have to travel a few hours to a capital city to get 120 film, or buy it online).

    Developing at home in Xtol.

    Anyway I'd like to do some slow shutter speeds in full daylight.

    I have an ND8 filter and an ND8 grad, and thats it.

    And I can shoot at f/22 (or f/32 fpr 12mp equiv detail).

    I've noticed Xtol doesn't like short development times, but say if I want to pull to ISO 10 what should I do? and if pull-developed correctly what effect will this have on the image? Blow the grain out?


    Consider the slowest film I have is 100, and I oly have one ND8 filter (and the grad which might be useful to stack to keep the sky down in some shots) and f/32, what's my best option for processing the film since I want to expose it for a few seconds?
     
  2. Rich Ullsmith

    Rich Ullsmith Subscriber

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    Depending on how much of this film you have, you might want to get a feel for its reciprocity loss characteristics, because it sounds like that is where you are headed.

    If you are planning to rate the film at ISO 10, then stop the lens down and add ND filters, you are probably looking at more than a few seconds.

    In any event, what you are describing is pushing your material to an extreme, and will require experimentation to achieve predictable results. Which, if you have plenty of the film and this is what you want to do with it might make it worthwhile.
     
  3. Huub

    Huub Member

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    Stopping down and adding filters won't change the iso of your film - but you will need longer shutter speeds to get the right amount of light on your film. Diluting your developer is probably the way to go. Try 1 + 4 and don't forget that you need about 100 ml stock solution to develop 1 rol of 120. I once rated HP5+ as 25 iso. Developed in XTOL 1+ 4 for 5 minutes. The negatives were a little dense, but still printable.

    Huub
     
  4. Athiril

    Athiril Subscriber

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    Well I figured from shooting in the middle of the day here with Sunny 16... it actually is brighter than Sunny 16 here unless overcast, itd only get to a few seconds by the looks of it with everything combined.

    I have 8 rolls of the stuff left.

    Starting from Sunny 16 and going down 3 stops from the ND8, and another 2 from the f/16->f/32, I get 1/3rd of a second.

    From ISO 100 to 10 thats going to be just 10/3 seconds, which is acceptable..
     
  5. drazak

    drazak Member

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    With shanghai film you are going to have very, very poor recipricity characteristics. at 1/3rd of a second you might have to expose for 1 second to have a proper exposure. Going from an EI of 100 to an EI of 10 is a 3 1/3rd stop change, not a 10 times change, 3 and 1/3rd stops, with an exposure of 1/3rd second at 100 is 2 seconds, not 10/3 seconds. At 2 seconds you will have a greater ammount of recipricity failure, I do not know if shanghai publishes data for the recipricity characteristics of their film, but there was a recent thread about recipficity failure. I also suggest googling LIRF for an excellent article by Patrick Gainer.

    Ben
     
  6. 2F/2F

    2F/2F Member

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    Pulling does not change the EI of your film (by much, anyhow). It lowers the contrast by reducing the negative density vs. normal processing, with the degree of this effect varying proportionally with the amount of exposure each part of the composition has received.

    If your film is ISO 100, and you want to get shutter speeds of two seconds on a bright and clear day (assume EV 15), all you have to do is some basic photographic figurin'. First of all, what is the equivalent exposure at your minimum aperture given EV 15? EV 15 = sunny 16 = '125 at f/16 = '30 at f/32. How many more shutter speeds do you need to cut to get to two seconds? First of all, consider reciprocity failure. With a conventionally-grained film, let's assume that when an exposure of 1 second is called for, you need to expose for 2 seconds due to loss of reciprocity. So if you are aiming for a two second exposure, you actually only need to count down to one second: '15, '8, '4, '2, 1. Five shutter speeds. (In an ideal world, you would have an ISO 3 film for this exposure.) Your filter takes care of three of those five stops. You are left having to overexpose by two stops. The fact that you are using negative film will let you print through at least one stop of this easily without a major change in contrast. There is also the very likely possibility that your working EI could be lower than box speed, and if so, that reduces your overexposure even more, making it so that in the end, you need to contend with possibly under one stop of overexposure in order to get a decent neg (not a "perfect" neg., but certainly a fairly easily printable one). You can surely use your X-Tol to pull a stop or so.

    In short, I would do an initial test by making the exposures at 2 sec at f/32 with the ND filter in place, then cut 25 to 30 percent off of your normal development time and see what happens. I have never pulled with X-Tol, but it can't be all that different from most other developers.
     
    Last edited by a moderator: Apr 16, 2009
  7. Athiril

    Athiril Subscriber

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    Thanks for the tip, hmm, perhaps I can use the water bath processing technique for this?
     
  8. 2F/2F

    2F/2F Member

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    That won't be necessary, IMO. It will require a good degree of experimentation, may not work so well on a modern thin emulsion film, and if it does work, will likely result in a neg that is flatter than it needs to be. Two stops over is really not that hard to deal with using "normal" pulling techniques. Remember that your pulling really affects contrast, not EI, so when deciding how far to pull, think about what you need to do to change the contrast from what it would be if you developed normally. You may decide that for the print you want, contrast will be perfect even with a two stop over exposure and normal development. In that case, you would not pull at all.

    In this case, I would probably pull one to one and a half stops. If a T-grained film or something like Tri-X 400, I might pull a full two stops to rein in that gnarly straight line.
     
    Last edited by a moderator: Apr 16, 2009
  9. ghost

    ghost Member

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    I agree with this- with this type of film, you won't need the extreme controls you are talking about- even if it is that bright out... if you have LIRF and dilution working in your favor that will be enough...