correct exposure to get a Zone VIII negative

Discussion in 'Pinhole Photography' started by Jose A Martinez, Jul 25, 2012.

  1. Jose A Martinez

    Jose A Martinez Subscriber

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    I'm working with a panoramic pinhole Holga and I want to know if I'm on the right path to expose a negative in zone VIII to determine the development time and know if I'm getting the proper density.

    I take the reading of the exposure meter against a flat even surface, a piece of gray cardboard, and make four shoots the length of time the mesure I got, I'm right?
     
  2. seadrive

    seadrive Member

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    The exposure meter gives you the exposure for Zone V, so you would open up three stops from the indicated exposure to get to Zone VIII.

    That's assuming you know the proper exposure index (EI) to use for your film (and to set on your meter), which is oftentimes not the same as the one on the side of the box the film came in.
     
  3. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    I think development is part of the equation. Zone VIII is highlight without detail. Expose for shadows develop for highlights as they say.
     
  4. RalphLambrecht

    RalphLambrecht Member

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    sounds alright. i look for zone viiito develop to a density of 1.29.
     
  5. Jose A Martinez

    Jose A Martinez Subscriber

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    Ok, the thing is that I'm testing for a pinhole camera, so instead of open up three stops I have to expose three times the exposure meters' time indicated, right?
     
  6. jnanian

    jnanian Advertiser Advertiser

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    hi jose

    it wouldn't be 3 times but you would double your meter reading for each zone/ fstop ...
    .
    for example if it said 1 second ... it would be ..2 ( 1 stop/zone), 4(2stops/zones) ... 8 seconds for 3 stops/zones

    sounds like a fun project !

    john
     
  7. Jose A Martinez

    Jose A Martinez Subscriber

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    so the progression is geometric, not arithmetic.
     
  8. Bill Burk

    Bill Burk Subscriber

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    Jose A Martinez,

    We haven't mentioned "reciprocity law failure" which means you may need to give even longer times if you are running into exposures longer than 10 seconds since you are using a pinhole...

    An old chart says it:

    If indicated time is ... give this much time

    1 sec ... 2 sec
    10 sec ... 50 sec
    100 sec ... 1200 sec

    ---
    Curiously, it is about the same as placing exposure on Zone VIII ... I wonder ...

    Is the whole purpose of moving exposure to Zone VIII supposed to correct for reciprocity law failure?
     
  9. polyglot

    polyglot Member

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    Correct. Exposure factor = 2 ^ stops.
     
  10. Bill Burk

    Bill Burk Subscriber

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    Yes
     
  11. Jose A Martinez

    Jose A Martinez Subscriber

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    Nice. I'm thinking in build a density curve from zone I to VIII. It's the homework for today
     
  12. ic-racer

    ic-racer Member

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    How did you do your Zone I exposure test? Do the Zone VIII the same way but give 3 stops more time rather than 4 stops less time. You did not do your Zone I test yet?? IF not, you need to, as you know any change to your exposure index will change the density of Zone VIII irrespective of development time.
     
  13. Jose A Martinez

    Jose A Martinez Subscriber

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    No I'm in the process, but I have to do it in the opposite direction, zone I is less time and zone VIII is more time. By the way, I'm using a Holga pinhole lens for Nikon, so I have to shoot and develop a roll for each test. So for a Zone I test I have to give 1/16th of the time needed for Zone V. The sequence for a full zone I to zone VIII should be the time exposure for zone V equals to 1 zone I 1/16, II 1/8, III 1/4, IV 1/2, V 1, VI 2, VII 4, VIII 8

    Right?
     
    Last edited by a moderator: Jul 26, 2012
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  15. Joe VanCleave

    Joe VanCleave Member

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    I might interject here to say that, if using panchromatic film, you will also need to account for reciprocity failure. Some films require less than others, for instance Fuji Acros.

    Good luck on your project.

    ~Joe
     
  16. Chan Tran

    Chan Tran Member

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    For what kind of film Ralph?
     
  17. Jose A Martinez

    Jose A Martinez Subscriber

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    I´m working with HP5+ developed in D76 1+1 for 11:30 mins. at 20º C. I made a roll with the exposure meter set at 125 ASA, thinking in the reciprocity failure. It is still washing, but, in an eye inspection I found it weak. I´ll measure it tomorrow when it´s dry, then I´ll know if I have to give longer exposures or give an stronger development, or both.
     
  18. ic-racer

    ic-racer Member

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    Maybe you mean to match what kind of paper or enlarger?
     
  19. RalphLambrecht

    RalphLambrecht Member

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    yes, but don' ignore the reciprocity compensation.
     
  20. Chan Tran

    Chan Tran Member

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    for what kind of film Tri X, HP5 ??? that the zone VIII would have density of 1.29? I checked characterisitic curves of many film and found that it also depend on how the film is developed. so the question is what type of film and what the development time would yield a density of 1.29 for zone VIII exposure?
     
  21. RalphLambrecht

    RalphLambrecht Member

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    for any and all fims!
     
  22. Chan Tran

    Chan Tran Member

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    I didn't know that Ralph and of course I am not good in B&W film so I am confused. Film has different contrast depending of the type of film as well as how one develops it. If Zone 8 is 1.29 then with different contrast the other zones wouldn't have the same values all the time right? I am kind of lost here.
     
  23. Bill Burk

    Bill Burk Subscriber

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    I really have to buy "Way Beyond Monochrome" so I can give it to you straight.

    But until then, I imagine Ralph is telling you where Zone VIII will fall on a Normal negative. When you want to accommodate different subjects you can use Multigrade paper to accommodate.

    -or-

    If you develop differently depending on subject contrast (as in traditional Zone System), then you could take Ralph's benchmark and use it as an aim point for Expansion and Contraction. For example N+1 you would want to develop until Zone VII test target hits 1.29, or for N-1 you would develop until Zone IX hits 1.29.
     
  24. Jose A Martinez

    Jose A Martinez Subscriber

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    I have the results of my first test roll. As I said before I shoot a roll of 35 mm HP5+, rated 125 asa, developed 11:30 m in D76 1+1. The net densities are:

    zone I 0.125; zone V 0.575; zone VIII 0.930. Taking as reference the information from the book "The Negative" of Ansel Adams give for what he deliberately put in quotation marks as "normal" to print in a difusion enlarger, the results are ok for zone I and V, but low for zone VIII, that most be between 1.25 and 1.35.

    My conclusion is that I'm exposing correctly but I need to increase the developing time.

    So I have to make another test.
     
  25. Bill Burk

    Bill Burk Subscriber

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    I agree with your assessment of the results.

    However, if you look at it on a graph and compare it with a drawing of an ideal graph. You will see that you are really close. This is what I would call being within 5% of the goal.

    It's good enough to use and you can go ahead and take photographs.

    Develop the next one longer, for sure. But even if you just do what you have here...

    Variable Contrast paper will be able to easily work with the negatives you have just made.
     
  26. RalphLambrecht

    RalphLambrecht Member

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    the zone system is often a bit like horse shoes and . handgranates.don't take it too seriously ,or your brain is going toend up in a knot