C-41 processing questions

Discussion in 'Color: Film, Paper, and Chemistry' started by srs5694, Jul 26, 2005.

  1. srs5694

    srs5694 Member

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    Hi,

    I've recently begun processing my own C-41 film -- the first roll is hanging to dry right now. (It looks OK at this stage, but of course I'll know more once I've scanned it -- I'll start on color printing once I'm comfortable with the color film developing.) I used the Dignan NCF-41 developer that was referred to in an earlier thread. I do have a few questions at this point, though:

    • Does anybody have a source (or recipe) for a C-41 stabilizer that does not contain formaldehyde? I'm just trying to minimize the toxicity of my chemistry whenever possible. I've seen references to such things, but have been unable to track them down. I'm in the US, so a US mail-order outfit would be good.
    • I'm using a blix recipe that I found online. The instructions with that blix say to blix for 6:30 at 100F, but because NCF-41 is a 75F developer, I'd prefer to blix at that temperature, or close to it. Dignan's original article says this is possible with extended blix time, but he doesn't say how much to extend it. (I realize Dignan says you can't over-blix, but I just don't want to waste time blixing for, say, half an hour if ten minutes would suffice.) Any tips?
    • I've seen some references to re-using blix, but I'm a little foggy on the details. Should I extend blix time with each re-use? What's the limit to re-using blix -- how many rolls per 250ml of blix?

    Thanks for any pointers on these issues!
     
  2. Nick Zentena

    Nick Zentena Member

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    If you want to avoid formaldehyde in your stablizer I think you'll need to switch to a complete Kodak or Fuji process. I'm not even sure about Fuji. From the enviromental view point my understanding is you'll still be using formaldehyde. The only difference is instead of it being highly concentrated in the stablizer it'll be in the other steps.

    No idea about the bleach times.

    I replenish my bleach. The bleach I use is low replenishment. 7.5ml per 36 frame roll of 35mm or similar. Other bleaches have higher replenishment rates. Depends on the formula.
     
  3. jd callow

    jd callow Moderator Staff Member Moderator

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    Kodak does not use it in their stab, but might as mentioned in the bleach or fix.
     
  4. srs5694

    srs5694 Member

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    The bottle of Kodak stabilizer I've got clearly states that it contains formaldehyde. Perhaps it's not present in some other Kodak stabilizer, though. Mine's marked "Stabilizer III & Replenisher."

    Another question: I'm now scanning my negatives, and they seem awfully grainy. I used Agfa ISO 200 film (actually Walgreens' rebadged Agfa, which I've used before). I've run across one reference that blix, as opposed to separate bleach and fix, can leave behind residual silver, which increases grain, so I'm guessing that's the problem, but if somebody's got another idea for improving this (say, increasing the blix time or using a developer other than NCF-41), I'd like to hear it. If switching to separate bleach and fix will help reduce grain, then I'll do so. Thanks.
     
  5. Nick Zentena

    Nick Zentena Member

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  6. jd callow

    jd callow Moderator Staff Member Moderator

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    You are correct I was reading the PR and not the bottle (I also use Stab III). Sorry I should have checked before posting.
     
  7. srs5694

    srs5694 Member

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    Thanks for the pointer; however, it seems that this product doesn't function as a stabilizer. Kodak claims this is OK for their current C-41 films, but also says "do not process films of older design that require a stabilizing agent for image stability." Unfortunately, that page doesn't have any information on whether a stabilizer is required for current non-Kodak films, and I haven't seen that information elsewhere, so I'd prefer to have some sort of stabilizer in my process, just to be on the safe side.
     
  8. Nick Zentena

    Nick Zentena Member

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    Then you'll have to stick with what you're currently using. They make a low formaldhyde version but I wonder if it just gets tossed out more often. The low formaldhyde version is

    FLEXICOLOR Stabilizer and Replenisher LF

    LF meaning low formaldhyde.
     
  9. edz

    edz Member

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    All stabilizers contain directly or indirectly Formalin save in processes such as Kodak's E-6 chain where the Formalin is in the pre-conditioner and not in the final rinse. Products such as Tetenal's C-41 STAB which claim to be Formalin free are while technically free of Formalin contain Hexamethylenetetramine (Hexamin) which degrades into ammonia and formaldehyde. Some like Champion's final rinse is even more complicated designed to be useable even in non-plumbing chain. They address concern for occupational exposure to Formalin but aren't really "healthier". With modern films one could probably use glutaraldehyde or some other protein fixative. Formalin, however, remains one of the cheapest and most effective solution. In the volumes we as "amateurs" are using I think its a non-issue. Yes, bathing in large quantities of formalin is not "healthy" but the exposure in the small amounts our darkrooms see of these low concentration rinses is very minor. I'm just guessing but I'd expect the metabolistic contract with Formalin is probably significantly higher among cigarette smoke (even probably 2nd hand) or the amount "gassed out" by a new set of cheap bookshelves or cabinets using particleboard. And that's nearly marginal compared to the amount of carcinogens--- Formalin is concerned, at most, a potential human carcinogen--- people merrily spew out from their motorcars.