Simple film math help

Discussion in 'Beyond the Basics' started by CineMan, Jun 19, 2006.

  1. CineMan

    CineMan TPF Noob!

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    Ok back to math class. A guy leaves New York on a train headed west. He has a camera with ISO100 film loaded in it. He is so excited to be on a train he doesn't realize that his camera is set for 200 speed film until after he shoots it. When he goes to the processor he needs to ask to push or pull how much to compensate?

    :wink:
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Welcome to the forum.

    I believe that would be a push of one stop. If you are shooting negative print film...I might not even worry about it. It has a pretty decent latitude and one stop should not stress it too much.
     
  3. bigfatbadger

    bigfatbadger TPF Noob!

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    Is it black and white? If so it's only one stop out so you might be able to get away with normal processing times, especiialy if you're printing yourself.

    If not, I think the rule of thumb is that you add two minutes to the exposure time, but there's probably more specfic information for your particualr film. What film is it?
     
  4. CineMan

    CineMan TPF Noob!

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    I did it intenionally on two rolls, because I was shooting in overcast Dublin, Ireland and thought exposure time would be too long for handheld if I set my camera to auto exposure at asa100.

    One is B&W the other is Color. B&W is AGFA APX 100. The color roll is, get this, Kodacolor II which expired in 1984.

    oh, and I am not printing or processing myself.
     
  5. bigfatbadger

    bigfatbadger TPF Noob!

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    Apparently you can develop it in rodinal for 11 minutes, but like Big Mike says, it'll probably be alright. I'd just develop the Kodacolour, if it's got this far it'll put up with a bit more!
     
  6. CineMan

    CineMan TPF Noob!

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    The place that I go to only uses Kodak Xtol developer for BW processing. Is this ok? And how many stops does 11 minutes equate to?

    Is one step in film speed equal to one f-stop?

    Oh and the most important shots on that BW roll are concert footage shot with a flash in a dark club, about 3 meters from the stage.
     
  7. Torus34

    Torus34 No longer a newbie, moving up!

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    The math:

    ASA/ISO film speeds in one-stop increments are 25, 50, 100 (125), 200, 400, 800, 1600, etc.

    If you're working in B&W, consider processing your own film. Also consider bulk loading.
     
  8. ThomThomsk

    ThomThomsk TPF Noob!

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    Like Big Mike said, it's a push of one stop, but don't sweat about it - your shadows will be a little dense but there isn't much that can be done about that now. With the 1984 Kodacolor, the effective film speed is likely to be a lot lower than what it says on the box, depending on how it has been stored, but colour negative film is amazing stuff and you could still get something usable. Let us see the results, OK?
     
  9. Mr. Krinkle

    Mr. Krinkle TPF Noob!

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    i think you have to push your negavite 40% more than the basic time. i did it with kodax tri-x which developes in 10 minutes on D76, so i developed for about 14 minutes.
     
  10. Mr. Krinkle

    Mr. Krinkle TPF Noob!

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    so, it will be 40% more or less of time for each stop.
     
  11. mysteryscribe

    mysteryscribe TPF Noob!

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    one stop forget it (((((it's film)))))

    but under exposed is always push... over exposed is always pull.. A lab worth a darn if you tell them what you did they will know what to do...
     

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