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Thread: Push and Pull

  1. #1

    Push and Pull

    Going from a pdf file i found a link to on the foma website regarding Foma Action 400, which if im not mistaken is the only emulsion recipe they use for 400 iso film..

    The pdf file puts forth that foma action 400 emulsion can be shot any where from 200 iso to 800 iso, and be properly developed by using the stock 400 iso time/developer combinations.

    With the time, and religious idolatry put forth into making development tables for different iso of each film... the question i have is, if the foma literature is accurate why has anyone bothered to do the alternate developing times

  2. #2

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    Re: Push and Pull

    -Exposure latitude is has no strict/standard definition
    -People standardize on different contrast/gradient preferences
    -Different developers, agitation methods, temperatures
    -Error/slop

  3. #3

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    Re: Push and Pull

    The terms "push" and "pull" are inherently imprecise and fuzzy themselves. Most who use the terms "push" and "pull" use roll film cameras and in-camera meters.

    "Pushing" is most commonly regarded as a technique to get usable photographs in low-light situations or when a really fast shutter speed is necessary. The film speed is rated higher, which underexposes the film, loses the shadow detail and ends up with the highlights exposed somewhere where the mid-tones should normally be. Then the film is overdeveloped to get the highlight density up to around where it should be. The result is a negative with no detail in the shadows, stretched-out mid-tones and contrasty highlights. It's a fine technique to "get the shot" in difficult situations, but does not deliver a full-toned print. The use of pushing for concert and rock-star photos has made it a "look" that many like. That's fine too. So, push, if that's what you want your prints to look like.

    "Pulling" is usually used for dealing with contrasty situations. Two things are normally happening here. 1. The contrast of the scene is so much that normal development blocks the highlights. 2. In-camera meters are often fooled into underexposing in contrasty situations. Hence, rating the film slower and reducing development fixes both problems.

    Since you're studying the Zone System, you'll note that pushing is related to N+ or expanded development, just with the addition of underexposing the film to get the shot. And pulling is similar to N- or contracted development. Neither pushing nor pulling are as specific or precise as Zone System expansions and contractions.

    As for Foma's recommendations: They are simply saying that "Normal" development will yield satisfactory prints from a range of film-speed ratings. Underexposing an ISO 400-speed film by a stop will lose some shadow detail. Foma likely feels this is fine, since pushing always loses shadow detail. Developing longer isn't necessary because the contrast can be dealt with in printing or in post-processing.

    Overexposing the film by a stop isn't an issue either. You just get a bit more shadow detail. People might want to do this in situations where they are used to "pulling." Again, development changes aren't needed because proper contrast can be achieved in printing. (There's a good argument to be made that ZS expansions and contractions are not as necessary as they were in the past with today's contrast controls in printing too, but that's another thread )

    Of course, nothing's stopping anyone from making development-time changes for expansions and contractions or pushing and pulling Foma film. Foma simply feels it isn't needed to get good results. Some may feel they get better results with changes in development time. These are the people that are posting their development times on the Massive Development Chart.

    Best,

    Doremus

  4. #4
    Drew Wiley
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    Re: Push and Pull

    Foma's film speed rating are infamously over-optimistic; take that into account too. And their provided technical info is minimal. You really do need to establish your own personal benchmarks of speed and development time.

    Second, these films are quite different from one another. The alleged 200-speed product has an exceptionally long straight line, so you'll get a more linear response in high contrast settings, whereas the 100 and 400 speed versions are more ordinary in that respect, with a medium toe, and you might have to boost the exposure more in order to get good deep shadow values.

    I personally dislike interjecting the terms "push" and "pull" with respect to Zone System theory. "Plus" or "Minus" development is less confusing, since the former pair of terms was generally used in relation to automated minor development tweaks to color film development instead.

  5. #5
    dave_whatever's Avatar
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    Re: Push and Pull

    Quote Originally Posted by Drew Wiley View Post
    Foma's film speed rating are infamously over-optimistic; take that into account too.
    This ��100%

    If you look at Foma’s published datasheet for the 400 emulsion you’ll see there’s only one developer where the film gets anywhere near 400 speed in, and that’s Microphen (a specifically speed boosting developer) assuming you’re after high contrast, and even then it’s only about iso 320 according to the graphs. So they are basically rounding that up to 400 and sticking it on the packaging. Everyone’s mileage might vary of course, but it does feel like a car manufacturer measuring the MPG while the car’s driving downhill.��

  6. #6
    ic-racer's Avatar
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    Re: Push and Pull

    Under exposing sheet film and over-developing it is not commonly practiced. Maybe like using a view camera hand -held. Not common, but not without merit for special circumstances.

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    Re: Push and Pull

    Quote Originally Posted by monochromeFan View Post
    the question i have is, if the foma literature is accurate why has anyone bothered to do the alternate developing times
    Because Foma is telling you that you CAN get away with working this way. They are NOT suggesting you'll get optimal results that way. For optimal performance, every film has to be tested and evaluated for your particular work style and the results you want. Simply following the "lowest common denominator" instructions provided by Foma isn't going to get you to "optimal".

  8. #8

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    Re: Push and Pull

    I have to say (I don’t actually have to but anyway) the questions OP posts don’t make much sense. Everyone keeps suggesting starting with some basics but that seems to be continually ignored, followed by more questions about random stuff from this or that tech document, book, video.

    If you don’t want to learn about this stuff, simply don’t. It will make very little difference in the end. Simply start with the manufacturer’s recommendations, try not to be sloppy, and alter things if you find consistent issues with a particular thing. Negatives too thin all the time? Lower your exposure index. Negatives too contrasty? Decrease development time. Negatives too flat? Increase development time. Read a basic Ilford or Kodak document about mixing chemicals, processing technique/steps and follow them.

    It’s not difficult at all to make negatives that will enable great prints to be made. Some people like to pretend it is for various reasons, or they really don’t understand it. Stay away from that noise and expose some film. You can master the negative in no time. Then focus on the printing (or editing if you are scanning negatives). That’s what to work on.

  9. #9

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    Re: Push and Pull

    Quote Originally Posted by Michael R View Post
    I have to say (I don’t actually have to but anyway) the questions OP posts don’t make much sense. Everyone keeps suggesting starting with some basics but that seems to be continually ignored, followed by more questions about random stuff from this or that tech document, book, video.

    If you don’t want to learn about this stuff, simply don’t. It will make very little difference in the end. Simply start with the manufacturer’s recommendations, try not to be sloppy, and alter things if you find consistent issues with a particular thing. Negatives too thin all the time? Lower your exposure index. Negatives too contrasty? Decrease development time. Negatives too flat? Increase development time. Read a basic Ilford or Kodak document about mixing chemicals, processing technique/steps and follow them.

    It’s not difficult at all to make negatives that will enable great prints to be made. Some people like to pretend it is for various reasons, or they really don’t understand it. Stay away from that noise and expose some film. You can master the negative in no time. Then focus on the printing (or editing if you are scanning negatives). That’s what to work on.
    Exactly right, spot on!!!

  10. #10

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    Re: Push and Pull

    The multiple development curves provided on the Foma pdf contradicts their earlier statement that "the film gives good results even when overexposed by 1 EV (exposure value) (as ISO 200/24 o) or underexposed by 2 EV (as ISO 1600/33 o) without any change in processing, i.e. without lengthening the development time or increasing the temperature of the developer used." Perhaps something got lost in the translation to english. The development curves tell the real story, and very few of the curves even suggest rating the film as high as ISO 320.

    Kodak and Ilford provide reasonable guidance on their film datasheets:
    Kodak "These development times are suggested starting points. Make tests to determine the best development time for your application."
    Ilford "Development times may need adjusting to suit individual processing systems and working practices."

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