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  1. #1
    bvy
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    C-41 - Drift By or Temp Averaging

    I'm curious if anyone is using "drift by" to maintain temperature in their C-41 film processing -- as opposed to using a water bath or some more elaborate set up (e.g. fish tank heater, slow cooker, etc.). Likewise, I'm curious if anyone is avoiding it for practical reasons. I'm looking for ways to simplify my C-41 processing. I'm NOT interested in tips on maintaining temperature, as I have that down already with a water bath -- but if it's not buying me anything that I can't easily fix when I print, then I'm willing to experiment with doing away with it altogether. (I don't mean to be belligerent, but I don't want the thread to evolve into yet another discussion on how to maintain temperature. I'm interested in this method specifically.)

    I use a plastic Paterson tank with two tempered prewashes (at about 105F). If the developer goes in at 102F, after three-plus minutes it's dropped to about 98F. I believe PE calls this "temperature averaging," and he and others make reference to Kodak documentation on this (though I can't find the actual source). If that's not an outright endorsement, it's enough for me to consider it seriously. But I'd like to hear about some practical experiences first.

    Thanks.

  2. #2

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    I use two pots on the stove if I have only one spiral tank to process. It's easier and faster than breaking out the roaster. I heat one pot to 150-160F and use it to quickly preheat the chems to 102F or whatever. The second pot I heat to 103F. Since developer is the only thing the strict temperature is needed for, and then only for a bout 3.5 minutes, this works fine. Temps for bleach/fixer steps will easily stay in their wider temperature range. NOTE: The pots I'm using have a think stainless base that hold heat well. With thinner bottomed pots you may need to be a little more watchful of the temp.
    Last edited by Lamar; 11-22-2013 at 07:33 AM. Click to view previous post history.

  3. #3
    Terry Christian's Avatar
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    I use a hot water bath for C-41 as well, just hot water out of the tap, no heater or stovetop. I've found that if you're going to err on the side of a degree or two too warm or too cool, err on the side of too cool. Too warm gives me a slight bluish cast. (I'm using Kodak Flexicolor.)

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    I just re-read your post and I think I missed your point the first time. You are actually wanting to avoid a water bath altogether, opting to start the developer time at temperature A and end at temperature B where (A + B) / 2 = developer temperature requirement. Is that correct? That equation would not be entirely accurate representation since the rate of temperature decrease won't be a linear function but I'm sure it's close enough given the deltas involved. I have not done this before but it is an intriguing proposition and seems entirely reasonable given development rates and rate of change of temperature are linear enough in the desired window for the given parameters. I guess if you really wanted to you could work out the correct equations and determine the rate of heat transfer coefficients for the materials involved then calculate your required starting temperature based on the ambient temperature in the room. Somehow you would have to figure in losses due to agitation, perhaps include that as part of the rate of heat transfer coefficient.
    Last edited by Lamar; 11-22-2013 at 09:12 AM. Click to view previous post history.

  5. #5

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    Correct development requires good temperature control. I always use a water bath. No drift or averaging.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  6. #6
    bvy
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    Thanks for the responses, Lamar, fully realize temperature decrease over time isn't linear, but as you say, it's "linear enough." Terry, that interesting because I've read things suggesting both to err on the too warm and too cool side. Gerald, I understand about correct development; I'm interested in experimenting in hearing from others who have done the same.

  7. #7
    Terry Christian's Avatar
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    bvy: The troubleshooting portion of the instruction sheet for the Rollei Digibase C-41 (liquid) kit also says that if the negatives appear more magenta than normal (i.e., the scans/prints more cyan) then the cause is developer that is too warm.

  8. #8

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    Some time ago, the German photo supplier „Phototechnik Kleinschmidt“ had a processing routine for their dilucolor c41, that will match your desires.

    Heat up the soulutions to 40-42°C in a water bath.

    Let the processing drum with the films preheat in that same water bath too.

    Fill in developer if temperature is reached, immerse drum all 15 seconds.
    Measure the developer temperature in the drum after 2 minutes and adopt final developing time, depending on measured temperature.

    38° 03:15
    37° 03:38
    36° 04:04
    35° 04:33
    34° 05:06
    33° 05:42
    32° 06:23

    Actually I don`t remember the exact times, I suppose values where rounded up/down to 5 seconds. I also have to say that I never tried this, but there where plenty of positive feedbacks in conjunction with this dilucolor chemistry a long time ago. But in the later editions of dilucolor this temperature drop method was not mentioned any more, so be warned that you will probably earn some unwanted side effects.

    The given times are from a german photo forum.

    http://aphog.com/forum/viewtopic.php...a6a29d#p168475

    Regards stefan
    Last edited by stefan4u; 11-24-2013 at 08:36 PM. Click to view previous post history.

  9. #9
    markbarendt's Avatar
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    I started with drift by the made several upgrades on water bath and temp control.

    Drift worked ok but the more accurate my temp control became the easier it got to print.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  10. #10

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    Quote Originally Posted by markbarendt View Post
    the more accurate my temp control became the easier it got to print.
    Exactly Why make work for yourself with negatives that are inconsistent and hard to print!
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

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