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Thread: BTZS Metering Question

  1. #11

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    Re: BTZS Metering Question

    Sorry Ian, I missed that you asked about development times with respect to SBR, not the Zone System.

    Below is a chart for the same film/developer combination. Note that for SBR 7 - which corresponds to a scene of normal contrast - the recommended development time is the same as previously given for N development.


  2. #12

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    Re: BTZS Metering Question

    Here is another graph which shows how effective film speed changes as we modify development time. This chart uses Zone System notation.

    Again, this chart is only for HP5+ in D-23 1:1 at 70 degrees F, but the principles are fairly universal.



    Note that film speed is around 250+ for N development, goes down 200+ for N-1 development, etc.

    Each film/developer combination will have its own characteristics, but this is nothing new: back in the 1970's Minor White suggested that we modify film speed by 10-15% with each level of expansion and contraction. He wasn't the first to discover it either. Note that since one f/stop equates to 50%, 10 or 15% amounts to a fairly modest adjustment in film speed: a fraction of an f/stop.

    With a scanning workflow, contrast can be increased ad infinitum. This eliminates the need for over-development which increases grain. If in addition we avoid scenes which require dramatic contraction, life becomes much easier. In photojournalism we have to bring back the photo whatever it takes. With Fine Art photography we can pre-select scenes which match the tonal scale of our medium.

    If we shoot this film at ISO 200 and rely on the scanner's wide dynamic range which gives us an automatic N-1 contraction, we can easily accommodate scenes of 1 more f/stop than usual. If we use an Infra Red viewing device and develop by inspection, each negative gets its own treatment, correcting any mistakes made in the field, which do happen, in spite of all this BTZS and Zone System... stuff.
    Last edited by Ken Lee; 29-Dec-2016 at 07:35.

  3. #13

    Re: BTZS Metering Question

    Develop by inspection? No problem, we'll fix it on the scan?

    I guess we just pour powder chemistry into the water "until it looks good more or less."

    Yikes.

    Sent from my 0PJA2 using Tapatalk

  4. #14

    Re: BTZS Metering Question

    You're consulting charts on exposure versus development but you have no idea of the development time until after the exposure.

    Sounds more like Before The Zone System.

    Sent from my 0PJA2 using Tapatalk

  5. #15

    Join Date
    Jul 2016
    Posts
    1,242

    Re: BTZS Metering Question

    Quote Originally Posted by Ken Lee View Post
    Here is another graph which shows how effective film speed changes as we modify development time. This chart uses Zone System notation.

    Again, this chart is only for HP5+ in D-23 1:1 at 70 degrees F, but the principles are fairly universal.

    Note that film speed is around 250+ for N development, goes down 200+ for N-1 development, etc.

    Each film/developer combination will have its own characteristics, but this is nothing new: back in the 1970's Minor White suggested that we modify film speed by 10-15% with each level of expansion and contraction. He wasn't the first to discover it either. Note that since one f/stop equates to 50%, 10 or 15% amounts to a fairly modest adjustment in film speed: a fraction of an f/stop.

    With a scanning workflow, contrast can be increased ad infinitum. This eliminates the need for over-development which increases grain. If in addition we avoid scenes which require dramatic contraction, life becomes much easier. In photojournalism we have to bring back the photo whatever it takes. With Fine Art photography we can pre-select scenes which match the tonal scale of our medium.

    If we shoot this film at ISO 200 and rely on the scanner's wide dynamic range which gives us an automatic N-1 contraction, we can easily accommodate scenes of 1 more f/stop than usual. If we use an Infra Red viewing device and develop by inspection, each negative gets its own treatment, correcting any mistakes made in the field, which do happen, in spite of all this BTZS and Zone System... stuff.

    I find this explanation containing a lot of knowledge. Of course, a too contrasty illumination can be an unnecessary complication to generate an art we visualize. Anyway I feel attracted by the challenge from very contrasty scenes like night photography. Then the N+/- comes short, as you point, using compensating development techniques to get sound results is another war

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