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  1. #1

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    C41 Developing at home question

    Hi Folks,

    I'd like to do some C41 developing in my Jobo CPP-2. I've bought the various Kodak Flexicolor chemicals, and I have a question on storage. I seem to have two options. First, I could mix up the whole batch of developer (1 gallon) and store it in small glass bottles, using a whole bottle each time I process film. Second, I could mix up fresh batches by using the appropriate amount of the concentrated solutions, with the idea being that the concentrates should keep better than a mixed working solution. Years ago, I used the latter process successfully with Flexicolor developer for developing Tech Pan. The problem with this is that total chemical contents aren't listed, and so I'd have to measure them, (which wouldn't be that hard.) Which method would you recommend?

  2. #2
    jd callow's Avatar
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    If you store it as you suggest I still wouldn't mix up any more than you'll use in a month.

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  3. #3
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    I have done what you suggest and it works.

    There is one minor problem. The first time around, you must pour out the chemicals to measure the quantity, and this aerates the developer portion of the chemistry (the stuff in the glass bottle) and so your very first batch of remaining concentrate will keep more poorly than subsequent packages that have never been poured out and then back into their original bottles.

    Otherwise, it works just fine.

    PE

  4. #4

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    Thanks Guys. Kodak says that mixed working strength developer will last 2 months in full, tightly capped glass bottles. My guess would be that opened concentrate would keep a little longer, especially if I keep the concentrates in the fridge. But as Mr Callow suggests, I'll have to be careful. I mainly plan on developing XP-2 Super, but I'll also do some 4x5 Fuji Pro 160.

    Another question: various sprays are available to extend the life of oxygen sensitive liquids, like wood finish.... However, these sprays are fairly expensive and somewhat of a pain to get. Most "dust-off" type of sprays seem to be some non-oxygen gas. Would spraying a small amount of Dust-Off into the bottle before capping be a good idea? Someday I'll probably pick of up cylinder of argon or nitrogen, but I just can't justify the expense at the moment.

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    All I can say is that nitrogen works, but then full bottles that are oxygen impermeable work also.

    I have kept RA color developer for 6 months mixed to working strength in full plastic Jobo bottles (1 L) and 3 months in full 5 L bottles. The Jobo bottles are very robust and air tight.

    C41 color developer has kept more poorly for me than the RA paper developer under identical conditions.

    PE

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    PE,
    I have c41 tanks (wing-lynch) which use nitrogen in the air space and maintain the chems at temp. What would be your best guess for how long they will remain good?

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    Mrcallow, I have no idea. I can say this though. Keeping the developer at working temperature shortens the lifetime somewhat over room temperature storage.

    Replenishment extends lifetime due to adding fresh sulfite and hydroxyl amine from the replenisher. They are both essential to color developer stability. Since I can get several months in closed containers under nitrogen at room temp, I would assume you could too, but that is no guarantee. A capped bottle leaks less than a lidded tank.

    I eyeball my developer and toss it when it gets to about a cola color. I usually test it with a strip of leader as well. The RA developer makes it for over 6 months (see above), but the C41 will not do as well. IDK why. They are both carbonate based and use HAS as stabilizer, but one is CD3 and the other is CD4 which is slightly more reactive. Maybe that is the reason.

    PE

  8. #8

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    PE,

    Thanks for your help. What kind of life are you seeing with the C41 developer? If I can get 3 or 4 months in tightly capped, full, refridegerated glass bottles; then I won't bother with measuring out small amounts of the concentrated solutions.

    -Peter

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    It's quite easy to divide the whole kit (I assume it's dedicated for minilab use, like the ones I get here?) between small bottles, each aliquot enough to make a volume of working solutions enough to fill your machine. I prefer to use small soda PET bottles - they have good screw-on caps, are airtight, and allow to squeeze out almost all residual air before closing. For smaller volume it's convenient to use large syringes (make sure they are full plastic, without rubber on plunger). But it's definitely a bad idea to keep color developer in half-full bottles. In return, the aeration is a must for bleach-fix mixture - it's essential for its activity (at least in modern mixes based on EDTA/Fe3+).

    Cheers from Moscow,
    Zhenya

  10. #10
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    I can get about 3 - 4 months in capped Jobo bottles which seem to be very oxygen resistant. I do put a nitrogen blanket over partially full bottles though. I divide one gallon up between 4 1 qt (liter) bottles filled to the top otherwise and put the cap on tightly. I use clear bottles so that I can judge the color change to the developer. There is no need to use dark bottles in a darkroom. There is not enough light, normally, to harm the solutions. All of my processing is done one-shot with the developer being discarded after use.

    Normally, you should NOT refrigerate any photographic solution, as it could crystallize out or 'oil out' with organic chemicals becoming insoluable. If that happens it is sometimes difficult to redissolve the chemicals. You can often only do it by using a hot water bath for fairly long time with stirring, and this only aerates the solution.

    Only an actual test will tell if any harm is being done by refrigeration and any treatment to redissolve any crystals or oils that may form. If an oil forms, it may be quite damaging to the solution, as the oil is probably not properly protected from oxidation.

    PE

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