Production Darkroom Troubleshooting - Streaks and Related Anomalies

Discussion in 'B&W: Film, Paper, Chemistry' started by daisy_33, Sep 30, 2011.

  1. daisy_33

    daisy_33 Member

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    Hello fellow enthusiasts,

    I work in a production black and white lab where we process anywhere from 40-60 rolls of customer film at a time. We're dealing with varying brands, speeds, and a healthy mix of 35mm and 120. We have a workflow set up that batches films with the same processing time together in the same tank. Our tanks vary in size from 8oz to 56oz, all stainless steel tanks and reels.

    Lately, we've been noticing some uneven development on the film coming out of the darkroom, especially in large even midtone areas like skies and sand. We've included a sample image (from a customer roll, 120 6x9) that depicts the phenomenon in question.

    Our current process is as follows:

    All at 68 degrees Fahrenheit:

    1. Pre-Rinse in H20
    5 minutes. Agitating for first 30 seconds, and then 5 seconds every minute.

    2. Develop in Xtol (stock) or Rodinal (1:25 or 1:50)
    Time varies by film. Agitating for first 30 seconds, and then 5 seconds every minute.

    3. Water Stop in H20
    30 seconds, constant agitation.

    4. Fix in Ilford Rapid Fixer (1:4)
    5-7 Minutes. Agitating for first 30 seconds, then 5 seconds every 30 seconds.

    5. Hypo Clear in Perma Wash
    1 minute, constant agitation.

    6. Wash in H20
    30 Minutes, running water bath.

    7. Final Rinse in Photo Flo 200
    Dip & Dunk Each roll individually.

    8. Air Dry

    We would love to hear any and all suggestions about what to try to get rid of these marks. If anyone can figure it out, it's the folks around here.
     

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  2. zsas

    zsas Member

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    Sorry to hear!

    One thought, I once read somewhere someone say something to the effect of the below re prewash:
    "show me a b/w film that says prewash before dev"

    Could that be it?
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    A few questions and a comment...

    The prewet is OK but a little long. Why is it 5' and has it changed?

    Is the rinse after development in running water or standing water?

    Did anything change recently?

    And a comment.... Except for size, those marks remind me of finger prints with dirty fingers. But on a 6x9 they are too small to be that. So........ I got nothing yet unless someone has very dirty or oily fingers.

    PE
     
  4. Ian C

    Ian C Member

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    I don't know about Rodinal, but X-Tol and most B&W film developers work best with 5 second agitations every 30 seconds after the initial 30 seconds of continuous agitation.

    See page 3 here:

    http://www.kodak.com/global/en/professional/support/techPubs/j109/j109.pdf
     
  5. George Collier

    George Collier Member

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    I don't know what to make of the pattern - I've not seen it before, and I can't really tell if the problem is over development in some areas (lighter values in the positive) or under development in others (dark areas). It's hard to know what a perfect neg would have looked like.
    One thing, though, about 120 film - in my experience, I do much better with evenness (including surge issues) if I agitate longer during the agitation time, then extend the interval (non-agitation time). It's as if the unevenness happens during agitation cycles, not when the film is still, and in order for the fresh developer to exchange all the way through the reel, it needs more agitation time. I also have found that gentle (but thorough) agitation helps minimize surge (which is not your problem, but thought I would mention it). My agitation period for 120 film is at least 15 seconds, whether every minute or every 3 minutes.
    Also, FWIW, I get much more even agitation from HC110 (1:60 or more) than with Rodinal, time and time again. I've almost given up on Rodinal with 120 film, which I don't get, but there it is.
     
  6. Bob-D659

    Bob-D659 Member

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    Was that roll from a multi reel tank or a single? Also with a long prewet and not enough agitation, you could have areas of the film that have a diluted developer on the surface.

    Oddly that frame almost looks like water vapour in the air accentuated by a red filter.

    Are you replenishing your Xtol, or. . . . . ?
     
  7. Ronald Moravec

    Ronald Moravec Member

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    Never prewet. Ilford warn against it. Kodak does not tell you to do it except for hand interleaved sheet film.

    You have a problem either from prewet or improper/insufficient agitation in developer or possibly fix. Badly fixed film can be refixed and repaired.

    99.9% of these problems are agitation problems.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    PREWET! PREWET! PREWET!

    It improves uniformity and it reduces the chance of air bubbles! This is based on over 60 years of hands on darkroom experience, 32 of which were in the Kodak Research Labs.

    PE
     
  9. artonpaper

    artonpaper Subscriber

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    I never prewash. I've been processing for well over 40 years. I read that one should never prewash with X-Tol. In addition, most streaks and stains come from contamination. The reels must be clean before processing. At Brooklyn College we now have the students fill, shake and dump their tanks 3 times with water between all chems. They get clean-as-a-whistle film.
     
  10. Worker 11811

    Worker 11811 Member

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    Just my guess...

    First, I would cut the prewash time down to a minute. Although time isn't critical, I think five minutes is too long. Cut it down to one minute, maybe two at maximum.

    Second, I would use a stop bath instead of plain water.
    I'm not complaining about the use of plain water as a stop bath. Sometimes, I use water too. But, in this case, I think you're in a special situation.

    If you have several reels of film, stacked up in a tank, you've still got development going on while you're pouring liquids out of and into the tank. Basically, you've got developer dripping down from the reels above which is still acting on the film, still developing.

    It takes me ten seconds to empty a two reel tank. I'm pouring my stop bath in just as the timer beeps. A four reel tank will probably take twice as long and a six reel tank will take three times as long. Right?

    If I'm right, that amounts to thirty seconds where developer is dripping off the film, still developing.

    With so much volume to empty and refill, I think you need to do what you can to stop development as quickly as possible. Every second counts. Only an (acid) stop bath can do the job efficiently.
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    I say "Do what works for you", but for me, I learned PREWET.

    And, I must say that Kodak taught that in the 40s and 50s in their publications on film processing. I have the old manual which shows a prewet being used and the text suggests it. I have done it since I was about 9 years old using that old manual as a teaching guide.

    PE
     
  12. CBG

    CBG Member

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    Several things hit me on the processing cycle described. And I'd like to know a couple of details the OP did not mention.

    The presoak seems wildly over-long. I've never had any need for a pre-soak, but it's gospel for others. But, why so long?
    I'd use an acid stop if processing gets the slightest bit out of kilter - and it's way out here.
    I'd want to see a couple of rinse cycles of rinse, agitate and toss clean water immediately after the fix and before the clearing agent.

    What are the disposal and replenishment schedules for all the solutions - which get discarded immediately and which get reused, and if so, for how long, and when are they tossed? How long does the mixed Permawash get used? Ditto the fix?
    What is the dilution used for the Permawash - is it as per mfr's recommendations?

    Have you tried discarding everything and starting with utterly fresh solutions to see if some solutions is either contaminated or just worn out?
     
  13. daisy_33

    daisy_33 Member

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    Thanks for all the responses, folks. Based on your ideas, I'll suggest we try the following:

    -Cut the prewash time by a bit. We used to do a 30s-1min prewash, we changed recently on someone else's suggestion, but because we were having similar problems. We might just change it back to eliminate one variable.
    -Change agitation to 5 seconds every 30 seconds. Agitation issues are one of our main suspects.
    -Try using an acid stop bath, especially for the mammoth 56oz tanks.

    Hopefully we will have some more to report in the short term.
     
  14. K-G

    K-G Subscriber

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    I agree with both PE and CBG ( partly ) .
    1. Prewetting helped me to get rid of the air bubles more than thirty years ago and I have kept on using it ever since.
    2. I would also use an acidic stop bath in order to minimize the risk of uneven development.
    3. If you use Xtol stock solution I suppose you replenish it. Is the replenishment ratio suficient ? I know Kodak recommends about 70 ml of fresh solution per roll but from what I have read and from my own experience a litle more ( about 100 ml ) is no problem.
    4. As the center part of the picture is bright on the print, the negative must be darker in these areas indicating increased developer activity. This can be the result of an un-uniform flow patern over the film surface during agitation resulting in developer exhaustion in the surrounding parts with darker sky. Do you have enogh air volume in the top of the tank so the developer will be stirred sufficiently when agitating ? Is the spacing between the film rows on the reels even ? Any of this in combination with to litle developer volume per film and/or unsufficiently replenished developer can be a problem.
    These are my personal thoughts . Good luck with the detective job.

    Karl-Gustaf
     
  15. Worker 11811

    Worker 11811 Member

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    BTW: I use stop bath and a water soak after development, followed by two more fill/dump cycles of clear water.
    Not only do I think it works better but I like to reuse my fixer until testing shows that it's spent. Rinsing with water not only stops the film better by first neutralizing the chemicals then by diluting them, it also stops developer and stop bath carryover into the fixer which, I believe helps my fixer work better, longer.
     
  16. vpwphoto

    vpwphoto Member

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    I'll toss this in.... Prewashing was an issue for me when I was using "soft water" the emulsion would swell.... now soft-water mixed with developer is no longer "soft". Anyway... I'll trust PE, I don't process too often and stopped prewashing with the soft water issue... I no longer run soft water into my darkroom.

    I'll also toss in that when you do things by manufacturer tested ways problems are fewer. I am not putting a wet blanket on your wish to try something new.... that is great and it is good to share your alternative methods. I have just learned (sometimes the hard way) that Kodak/Ilford don't have folks like PE on the "books" just because they like to pay people.

    It still cracks me up that a professor once tried to tell us that "stop bath" was too harsh of a jump from alkaline and we needed a "gentle" transition as if film had feelings. That being said I do occasionally do a "water bath transition" from developer... my thinking and I think A.Adams wrote about it is that developer is exhausted first in the dense areas of the negative and the developer in the "gel" of the thin areas keep acting.... I'd like PE to weigh in on this ... it seems to make sense to me.

    Looked at OP's original post/photo.... sure looks to me as if agitation is too little ..( some call it Bromide Burn). I had similar results with some film 20 years ago... I went from over agitation to nearly none with 4x5 in handers (still can not get good results from hangers)
     
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  17. Photo Engineer

    Photo Engineer Subscriber

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    In dense areas of a negative, we measured an acidic pH during development unless the developer was highly buffered. We did this by coating a ballasted indicator dye as an underlayer, coating an indicator dye in the layer and then measuring the color change as a function of density. Many tests show that a stop cannot harm a properly hardened coating. BTW, I demonstrate this to my students under very harsh conditions. We use an unhardened coating in a carbonate developer followed by a stop! :D Our reference is a hardened coating.

    PE