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Thread: ISO and C41 ?

  1. #1
    VincentM's Avatar
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    ISO and C41 ?

    Hello,

    Im used to B&W development and I will try soon C41. One thing is troubling me though: nowhere I read about ISO when developing C41... Does it change development time Whether I have 200 and 400 films?

    My second question is what shall I do when I shot a C41 expired film rated at 200iso one stop underexposed ie: 400iso? Shall I develop longer ? 3mn30s?

    Thanks
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    Greg Davis's Avatar
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    All C-41 films, regardless of ISO or brand use a standard development time of 3:15. For a one-stop underexposure, extend that development time to 3:45.
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    Hi,

    C-41 is a standardized process, as is E-6. That means that the film makers design films such that they work with a process that is set in stone.

    The amount to add for a push will vary from emulsion to emulsion. Kodak Portra 400 and 800 follow the 30 seconds per stop for the first two stops rule. Others may vary, though those are good starting points for experimentation. And those were times for the old Portra 400 (VC and NC), which has now been replaced, so I don't know if new Portra 400 follows the same pattern. Not every film is equally sensitive to pushing, so make sure you experiment if you plan on doing that often.
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    VincentM's Avatar
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    Thanks guys great info. I m now ready to start
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    hpulley's Avatar
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    Yes, makes you understand why they went for Chromogenic B&W films. Processing many different types of B&W film was a royal pain for them...

    Makes me wonder why there is such mystique for home C-41 development. One time, one temperature, one developer, so much simpler than B&W in many ways!
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    That is interesting. The rinse times are 3:15 at 15 to 105 F in the C-41 process I know (one after bleach and one after fixer).
    2F/2F

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    Athiril's Avatar
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    It's +15% stop consecutively, as opposed to 30 seconds, which equates to 30 seconds for the first two, but not exactly. After 2 stops, it needs more than +15% imho.

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    The JOBO/Unicolor 1L kit lasts longer than a day! You don't need to save up so many rolls. I saved up 9 rolls the first time I used a 1L kit just in case but that one lasted for 24 rolls over 4 months! So the next batch I mixed up and processed 4 films, then 1-2 weeks later, 4 more films. Then 1-2 weeks later, 3 films... The stuff lasts much longer than the instruction sheet says.

    I do 3 rinses, then stabilizer. With just 2 rinses I find there is still some pink in the water so better one more rinse I thought.
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    Athiril's Avatar
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    12? Even 8 is a lot.

    I go like this pre-soak to get up to temp -> C-41 Dev -> Bleach -> open tank and rinse reels with 100-200ml water, tip out -> Full Rinse/Wash, plunge reels up and down -> Fixer -> Same thing with the 100-200mL -> Same Full/Rinse Wash again -> Let soak in water (same temp as dev btw +/- a few) for 5 min, it'll come out pink -> Soak Stabiliser III for a few min.

    Though I am using Flexicolor.



 

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