Re-bleach cut C41 negatives?

Discussion in 'Color: Film, Paper, and Chemistry' started by keyofnight, Jul 27, 2013.

  1. keyofnight

    keyofnight Member

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    Hey folks! I took a shot at processing C41 negs, and I screwed it up: I didn't aerate the bleach enough or bleach them for long enough (one or the other). I didn't know I screwed up until I tried to scan them a week later—after I had already cut the negs.

    How can I bleach them again? I don't have access to a darkroom, so I can't just throw them in trays or something like that. I was thinking about taping the cut pieces back together (on the non-emulsion side) and respooling it. Would that work, or is that just a crazy idea?

    (I accidentally posted this to the wrong forum… mods, could you help me out?)
     
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  2. BMbikerider

    BMbikerider Member

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    What makes you think you didn't bleach them sufficiently? Did you use separate bleach and stop baths or was it a single bath? If it was a single bath you could have a go at bleaching them again but I wouldn't hold your breath about the results though. If it was separate bleach and then fix and the film had been through the fixer then re-bleaching will not have any effect.
     
  3. brucemuir

    brucemuir Member

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    Yes, why do you think they are mis-bleached?.
    It's a bit odd to judge C41 negs if you are new at it.

    Sometimes they can look quite dense.
     
  4. markbarendt

    markbarendt Subscriber

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    It can be done in the light.

    I don't know what kind of reels you've got but may be able to put the strips in place without taping.

    When rebleaching or refixing is necessary you just "skip the developer" and "do the rest" of the process.

    Bleach sets the film up for fixing, they are interdependent processes, and the stabalizer/rinse is then naturally required to finish.

    Some extra time in these chems, on the original run or as you plan here, is just fine because these processes unlike the developer are supposed go to completion.

    The developer is the only bath that has to be timed to exactly the proper time.
     
  5. pentaxuser

    pentaxuser Subscriber

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    Here's a suggestion: Tell us the exact process and times used and if possible scan as accurately as possible the negs and attach them.

    That is going to be the quickest way to get to answers that will help you

    pentaxuser
     
  6. fotch

    fotch Member

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    What others have said plus taping is a bad idea!
     
  7. keyofnight

    keyofnight Member

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    I got that impression from the entire process. When I first processed them, they looked a little dark in comparison to other negatives I've seen in the past. They were also hard to scan—harder than it was to scan negs processed at a lab. The image was desaturated, the grain was worse than I expected, the colors had a 70's kick to them. It didn't look like a color shift, just like a general haze—not a bad effect, but I know this film has a different look to it by default. Here's an example:

    [​IMG]

    I took a roll of film from the same batch to the local photo lab, and their processing left the film base way lighter, and I can see more under a loupe than I can in the ones I processed myself.

    I did a some research and I found this, which describes the problems I have to the letter:

    "Insufficient bleaching of a C41 negative, e.g. due to exhausted or improperly oxygenated bleach, will cause the film base to be unusually dark. There will also be residual silver left in the film, which forms a monochrome image overlaying the colour image, which reduces saturation and increases contrast.

    What you have is an accidental partial bleach bypass.

    To cure the problem, redo the process starting from the bleach step using fresh bleach and fixer. Don't forget the stabiliser. The negatives should come back to normal after re-bleaching and fixing; if not then there are other problems."

    …and that's why I think it was improper bleaching: I'm a nerd and I look stuff up incessantly.

    I use Flexicolor SM chemicals in a steel hand tank and a waterbath at 100°f. I follow Kodak's small tank instructions—all the times I used are there.
     
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  8. keyofnight

    keyofnight Member

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    I have Hewes SS reels.

    If I can do this in the light, I'll just do it in trays in the bathroom. :D
     
  9. markbarendt

    markbarendt Subscriber

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    Yep that works.
     
  10. keyofnight

    keyofnight Member

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    You were right... I tried re-bleaching the film and it didn't do much of anything. Again, I use the Flexicolor SM chemistry—the bleach and fix are separate. Could you tell me more about why it had no effect, and what I can do to prevent this from happening again in the future?

    (For reference, here's what I'm dealing with. My hand-processed film is on the left, and the lab-processed film is on the right. Both are Ultramax 400.)

    IMG_7895.jpg
     
  11. cmacd123

    cmacd123 Subscriber

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    after bleaching you would have to fix, wash and stabilize. (whatever the final rinse is called in your kit.) just bleaching would likely not change the density much.
     
  12. foc

    foc Member

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    From your description I thought at first it was a retained silver problem with your bleach (ie: not bleached enough or reusing bleach with out proper rep), but on seeing you shot of the negs I think your problem lies elsewhere. Could you have over developed it? Was the dev temp correct?

    I don't have any experience with home kits but have 34 years experience with pro C41 processing. Standard machine C41 is dev 3' 15" @38C +/- 0.1C. The rest of the chemistery has a +/- 2C, you might even get away with more but I never tried it.
     
  13. keyofnight

    keyofnight Member

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    I have an older mercury thermometer that I calibrated using ice water. I'm fairly sure I kept it at 100°f for 3'15". I do know that I'm a pretty slow getting the developer in and out of the tank, so I may have overdeveloped them. I couldn't have done it for any more than 5 seconds, though. Would that cause such a dark film base?
     
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  15. Rudeofus

    Rudeofus Member

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    Is there a remote chance that you were given the E6 CD instead of the C41 CD by accident? Also, just for sake of experiment, you could try to bleach a small test clip with a ferricyanide bleach, just to see whether you bleach has gone bad and it was retained silver after all.
     
  16. clayne

    clayne Member

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    If you rebleached without fixing you should definitely see a difference - in that you shouldn't even see the darkness anymore. However, you NEED to fix or that rehalogenated could technically print out since its now "live" again.

    If you saw no difference with your bleaching, and your negs sure look to me like they have silver in them, then your bleach is toast. Bleaching should make the visible silver go nearly invisible. Redeving will bring the silver back to the metallic state OR fixing will remove it permanently.

    I'd make it a priority to figure out what's going on as if the silver is in the rehalogenated state without being fixed that's a bad thing. There's no risk though if your bleach is toast because its still metallic silver.

    That being said it seems pretty unlikely your flexicolor bleach just decided to stop working, especially considering it's not a blix.
     
  17. keyofnight

    keyofnight Member

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    I'm thinking that's the problem, though… I don't think it ever worked. I've only tried to process 2 rolls, and they both showed the same problem. It's a shame because the whole set cost a lot more than I should've paid at first. I've heard about bleach failures in other kits with separate bleaches. I took a huge chance in using Flexicolor SM in such a large batch. :/ Win some…lose some.

    I don't have any ferricyanide bleach to test with. I'll see about acquiring some.
     
  18. clayne

    clayne Member

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    If the bleach given to you was bunk, do not fret. This only means you effectively did a 100% bleach bypass or skip-bleach on those negs.

    At any point, you can rebleach and fix to remove the silver. As it is now, the silver is in a metallic fixed state, and you're at no risk of printing out.

    Ferricyanide bleach is easily made with raw potassium ferricyanide powder (completely safe) and potassium bromide. Both available from Artcraft chemicals cheaply. Alternatively you can buy a smaller quantity already mixed up. Use a small amount of concentrate with water you have your working bleach. The concentrate lasts a very long time, the powder forms pretty much indefinitely.

    The entire purpose of bleach is to rehalogenate metallic silver back into silver halide. This means it becomes light sensitive, redevelopable, *and* removable via fixer if not redeveloped. It doesn't matter if you bleach in full light, because the image forming silver is all that is left at this point (since you already fixed before-hand).

    Where'd you get the Flexicolor bleach from?
     
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  19. keyofnight

    keyofnight Member

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    I got my bleach from a big camera shop that has a Kodak account: Glazer's Camera in downtown Seattle, WA. They ordered direct from Kodak.

    So, I guess I'm going to try to acquire potassium ferricyanide and potassium bromide. Two questions…if I switch to a ferricyanide bleach permanently, how would that change my process? Also, how is it even possible that my bleach is bad in the first place?

    I just want to make sure I haven't made some mistake that I'll end up making again...
     
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  20. clayne

    clayne Member

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    Seems almost impossible that Kodak shipped you bad bleach. What time/temperature did you use the bleach at?
     
  21. keyofnight

    keyofnight Member

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    It does seem impossible, but I don't know what alternative explanation I could give. The bleach is already a working solution, so I didn't have to mix it with anything… people have reported success with these chemicals. I aerate the bleach just how others have said they have: keep 500mL of working solution in a 1L bottle, shake like crazy, open the cap, blow in air, shake some more, repeat. I tried to keep the bleach at 100°f like the processing manual says, but the manual also says there's wiggle room (75°f to 105°f if I remember correctly).

    What else could I have done wrong? Could I have contaminated the bleach somehow? I'm not sure how I would've.

    I've run out of ideas.—lol
     
  22. clayne

    clayne Member

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    Do you have the exact CAT number for the bleach?
     
  23. keyofnight

    keyofnight Member

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    The CAT is 882 4690.
     
  24. clayne

    clayne Member

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    Looks like standard working solution small tank stuff. How much wash did you do between dev and bleach? I have a feeling there's nothing wrong with the bleach, but unfortunately I don't know of a good testing regimen for this type of bleach other than physical immersion of the negative in a tray and visually watching it while bleaching. However, I also could be wrong in that this particular bleach may not act the same way as a pot-ferri bleach at least with regards to visual inspection.

    PE would know more than I here.
     
  25. Rudeofus

    Rudeofus Member

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    One thing I did notice in the instructions is that each bath is mixed to a different quantity. Is there a remote chance that you mixed the developer to only one liter?
     
  26. keyofnight

    keyofnight Member

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    The processing manual (Z101, I believe) gives solution ratios. I do the math to mix up a 500mL batch, and I use it one-shot.

    I fill, invert once, dump, fill, invert 5 times, dump. That should be enough, right?

    Yeah, I've just about run out of ideas, and I'm not sure I'm getting any closer to a solution.
     
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