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  1. #1
    OldBikerPete's Avatar
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    Hello from Australia and DC-41 in JOBO CP

    G'day from Melbourne. I've been lurking around for a couple of weeks now and thought I should announce myself.
    I have been photographing for ummm.. over 40 years now, in 35mm and 6x6, 6x7. Have done about 20 weddings about 30 years ago and have home processed E4 using formulae out of BJP and C22 using Tetenal kits.
    I have recently divested myself of all photo gear and reinvested the proceeds into a Canon D20 for happy snaps and a Wista 45 for serious work (landscapes in color).

    I also have a question regarding processing C-41. I am in the research stage of acquiring a JOBO CPE-2 for processing color negatives, would the Dignan Divided developer be appropriate in this machine? Would the amount of agitation in the second developer be too high?
    The only C-41 formulae I have seen I have found from posts on this forum (Dignan divided and Laut) and I am tracking down a copy of British Journal of Photography Annual (the final 1994 edition published in 1993) because
    that's where I got my E4 formulas from.

    Does anyone have any comments, suggestions on those or any other developers? Photo_Engineer, I've read a lot of your comments and have taken them on board and intend to experiment along the lines you say have been neglected. Do you have any further hints to drop? :-D

  2. #2

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    Can't help with the c-41 but welcome from another photog in Melbourne.

  3. #3
    jd callow's Avatar
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    A jobo and Kodak chemistry works without issue. I have developed countless rolls and sheets this way.

    *

  4. #4
    PeterB's Avatar
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    Quote Originally Posted by OldBikerPete
    G'day from Melbourne.
    Welcome from a Sydney APUGer who probably shares a few things such as a first name, country of origin, and some hobbies (electronics and photography).
    I'm an Engineer/Scientist and was wondering as a scientist what kind of scientific things you get up to at work?
    regards
    Peter

  5. #5
    Nicole's Avatar
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    Warm welcome from another Aussie - on the west coast here
    Kind regards, Nicole

  6. #6
    Photo Engineer's Avatar
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    Pete;

    I have good reason to believe that divided developers will not work well with C41, most especially in a Jobo due to the high agitation.

    In a multilayer film (color) diffusion becomes very important both inward and outward. As a result, the yellow layer will lose solution "A" faster than the cyan layer leading to crossover. I would go with a low agitation situation with a color divided developer if that is what you want.

    On another side of the coin, the edge effects and color correction via DIR couplers and inhibition by iodide rely on diffusion as well, and in low agitation may lead to other effects such as exaggerated edges or bromide/iodide drag. As bromide or iodide goes up in the vicinity of development, density of solution goes up and therefore the halide heavy solution moves downward. In addition, pH effects are more severe in color due to the 6 silver layers and high level of silver. Coupling (dye formation) is quite pH sensitive and this can upset color balance.

    You will be walking a tightrope here, I'm afraid, and I really don't have enough personal experience to judge. I use a Jobo myself and use C41 chemistry straight from Kodak ( being just 5 miles from the plant).

    I have tried other mfgrs developers and seen the curves and data resulting, and some of it was not pretty. I don't want to slam them, but the only good processes I have seen come from Fuji, EK and Agfa. Of the available commercial products, the rest ran far behind in the tests I saw and the published formulas were so far from the real ones that they were not even tested. Of course, the last tests I saw are about 10 years old, so these mfgrs may have updated their formulas. I cannot speculate. If you do go down this road, I would be interested in hearing of your results.

    PE

  7. #7
    Glenn Mathison's Avatar
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    Welcome from Sydney. I leave the C41 to the lab, only do B&W at home, so can't help there.

    Good to see another Australian crop up...

    Regards
    Glenn

  8. #8
    Carol's Avatar
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    Hi there and welcome Peter from over the border in S.A.
    Cheers
    Carol

  9. #9
    OldBikerPete's Avatar
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    Quote Originally Posted by PeterB
    Welcome from a Sydney APUGer who probably shares a few things such as a first name, country of origin, and some hobbies (electronics and photography).
    I'm an Engineer/Scientist and was wondering as a scientist what kind of scientific things you get up to at work?
    regards
    Peter
    PeterB, I've responded in a private message.

    Thanks, everyone for your warm welcome and constructive comments. photo_engineer your comments reinforce my own initial reaction to DC-41, thank you - but I still intend to investigate self-mix developer. You don't happen to recall the C-41 process patent number offhand do you? I've spent a couple or so of hours running searches but I don't know if I've found the right one/s yet.

  10. #10
    Photo Engineer's Avatar
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    Peter, I have lost the exact patent reference. I spent some time trying to find it again, to no avail. Here is where I started:

    http://patft.uspto.gov/netahtml/search-bool.html

    My search criteria were; negative film, Eastman Kodak, and processing but the number of patents is truly amazing for some searches.

    Since I really don't mix anything but Blix, Bleach and Fix for color, I just never held on to the developer formulas.

    PE

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