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Thread: Ilford - new reciprocity failure compensation factors

  1. #61
    Dave Karp
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    Re: Ilford - new reciprocity failure compensation factors

    Thanks Michael.

  2. #62
    Drew Wiley
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    Re: Ilford - new reciprocity failure compensation factors

    The Zone System, despite its limitations, is still the best common denominator jargon for sheet film users that I'm aware of; so I often use that terminology on forums even though as an exposure model it now exists only in my rear-view mirror.

  3. #63

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    Re: Ilford - new reciprocity failure compensation factors

    Quote Originally Posted by Drew Wiley View Post
    The Zone System, despite its limitations, is still the best common denominator jargon for sheet film users that I'm aware of; so I often use that terminology on forums even though as an exposure model it now exists only in my rear-view mirror.
    Drew, I'd say more:

    What limitation? Any limitation?

    > It is also visualization system.

    > It is based in spot metering interesting spots in the scene

    > It says what density we will obtain in the negative for each scene spot depending on the exposure.

    > For reciprocity failure, calculations should also be based on the ZS, knowing where zones in the scene will end in the negative zones...

    Where is it the flaw ??? We just need to know well our film, what toe and shoulder we have, but this is with any metering strategy.

    Anyway (of course) we can use any other metering strategy we want, and also we can further use other advanced techniques like scim on it, but if ZS+BTZS is not complete, I'd ask that somebody explains it to me why !!!

    The single alternative (IMHO) is incident metering, for what it's worth...








    https://www.alanrossphotography.com/...emandmetering/

  4. #64
    Drew Wiley
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    Re: Ilford - new reciprocity failure compensation factors

    It's just a shorthand method for pigeonholing exp placement and development. It's all some people need. More of a teaching tool.

  5. #65
    Drew Wiley
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    Re: Ilford - new reciprocity failure compensation factors

    I use spotmeters for everything except lab work. But the ZS is quite clumsy for color film work, and is no substitute for real sensitometry under special conditions, like extreme lighting or matched b&w color separations. If you like to work with a variety of films, formats, and developers, you almost need a different zone system for each. It relies too much on contraction to handle high-contrast, at the expense of micotonality In other words, it's a good starting point, but certainly no silver bullet.

  6. #66

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    Re: Ilford - new reciprocity failure compensation factors

    Quote Originally Posted by Drew Wiley View Post
    If you like to work with a variety of films, formats, and developers, you almost need a different zone system for each.
    Ok, Drew... but speaking about BW, ISO box speed is always 3 1/3 stops under meter reading (because ISO definition of speed point), so with standard development always it works similar.

    If we use a development that is not the standard one then we just need to know the effective speed resulting for that process, and then ZS works the same again with the new speed... does not ?

    Of course film toe, and higlight latitude knowledge (shoulder and DMax) is also an important thing, but this is just knowing the nature of the film we use...

    So I'd say that with ZS we guess the resulting densities in the negative, and depending on toe/shoulder nature we can guess or not having some deatil in Z-I and how highlights are to be blown beyond Z-VIII. Do we need something else ?

  7. #67

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    Re: Ilford - new reciprocity failure compensation factors

    Quote Originally Posted by Pere Casals View Post

    If we use a development that is not the standard one then we just need to know the effective speed resulting for that process, and then ZS works the same again with the new speed... does not ?
    Underlying the ISO method is the Delta-X fractional gradient estimation. Delta-X tells us that speed doesn't decrease as much as the Zone System says it does, when contrast is reduced, and that speed doesn't increase as much as the Zone System says it does, when contrast is increased. The Zone System overestimates the change in speed because it relies on a fixed density speed criterion.

    Quote Originally Posted by Pere Casals View Post
    So I'd say that with ZS we guess the resulting densities in the negative, and depending on toe/shoulder nature we can guess or not having some deatil in Z-I and how highlights are to be blown beyond Z-VIII. Do we need something else ?
    Zone System expansion/contraction is based on "fitting" the negative to a paper grade. Strictly speaking this is not based on print quality.

    Many people also come away from studying the Zone System (and/or related systems) with a false impression of the level of precision one can achieve (or needs to achieve) in making negatives. In reality "place" and "fall" are approximate due to metering technique, flare, etc.

    I think the best feature of the Zone System is that it gives us a language.

  8. #68

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    Re: Ilford - new reciprocity failure compensation factors

    Quote Originally Posted by Michael R View Post
    Underlying the ISO method is the Delta-X fractional gradient estimation. Delta-X tells us that speed doesn't decrease as much as the Zone System says it does, when contrast is reduced, and that speed doesn't increase as much as the Zone System says it does, when contrast is increased. The Zone System overestimates the change in speed because it relies on a fixed density speed criterion.
    IMHO ZS does not speak about speed change, to me it says expose for the shadows and adjust development to not have a excessive (or to low) density in the highlights.

    Beyond exposing to have detail enough in the shadows, and cooking to have a desired density in the highlights... can we do something else ?


    Quote Originally Posted by Michael R View Post
    Zone System expansion/contraction is based on "fitting" the negative to a paper grade. Strictly speaking this is not based on print quality.

    Many people also come away from studying the Zone System (and/or related systems) with a false impression of the level of precision one can achieve (or needs to achieve) in making negatives. In reality "place" and "fall" are approximate due to metering technique, flare, etc.

    I think the best feature of the Zone System is that it gives us a language.
    The metering technique has to include flare, or even better, one has to remove flare, this is prety easy, if we have a 500mm image circle in a 8x10 camera, then 80% of light bounces in the bellows, a front hub solves that.

    Let me reiterate... if we expose to have detail enough in the shadows, and then we develop to have a desired density in the lights... what else can we do ?


    Well... we can use film toe/shoulder to compress highlights and shadows to leave what we want for the mids, or we can take a linear capture and do it in the printing process...

  9. #69

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    Re: Ilford - new reciprocity failure compensation factors

    Quote Originally Posted by Pere Casals View Post
    Let me reiterate... if we expose to have detail enough in the shadows, and then we develop to have a desired density in the lights... what else can we do?
    You have to make it more complicated than that or else it doesn't qualify as alchemy.

  10. #70

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    Re: Ilford - new reciprocity failure compensation factors

    Quote Originally Posted by Pere Casals View Post
    Let me reiterate... if we expose to have detail enough in the shadows, and then we develop to have a desired density in the lights... what else can we do?
    You have to make it more complicated than that or else it doesn't qualify as alchemy. You have to waive your hands a couple of times at least.

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