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  1. #1

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    Color Developer Quest

    After much research, I found a really good C-41 developer formula right here on APUG, and when I use it, I find that I can scan my negatives and need very little color correction.

    Not so, unfortunately, with the formula I am using for ECN-2 films. The developer I am using for that is found here:

    http://www.apug.org/forums/forum216/...orial-use.html

    Unlike C41, which has been the subject of much experimentation, there really aren't too many unofficial developers published for ECN-2. The above was really just a slimmed down version of Kodak's published formula, by removing certain chemicals that are hard to find or very expensive.

    So here's the deal. The negatives develop to a good density, commensurate with the ISO of the film, but regardless of the particular ECN-2 film I use, a straight scan always comes out with a green cast. This can be corrected on the computer, or if i print analog, the cast can be corrected by filtration changes on the enlarger. There is no serious color cross-over or anything, just that the images always are a bit green if not corrected.

    Because this happens across film stocks, my assumption is that the developer is not developing each layer correctly. It is perhaps developing the red and blue layers less than the green layer.

    I am not a chemist -- but if I wanted to tweak the above formula, what things would tend to move the development in the right direction? I am hoping Photo Engineer or a similar inordinately knowledgeable peson could give me some things to try. I don't want to buy overly exotic chemicals, but I would love to end up with a formula for developing ECN-2 as successfully as C41.

  2. #2
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    Kodak has freely published the ECN2 formulas for all to see.

    PE

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    Hi PE - I realize this - and the formula I linked to in the previous APUG thread was an exact copy of a published formula minus certain hard to get chemicals (such as Kodak anti fog #4, Kodak Antifoggant AF-2000). To restate my original question, I would love to know what those chemicals do, and whether there are any non-proprietary substitutes that I could try.

  4. #4
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    Well, first, the formulas you refer to are not exactly the same as those published by EK, and I suspect that the difference in KBr level (an antifoggant) is there to compensate for the absence of AF2000 (another antifoggant). However, this change probably depresses edge effects and thus may make the film less sharp. So, IDK what to say to you except that it is the old Key + Lock situation. The film was designed for the developer and vice versa.

    I'm sorry but someone has posted the name for AF2000 here somewhere. OTOH, you might try the following:

    Benzotriazole, Phenyl Mercapto Tetrazole, or 5 nitro benzimidazole nitrate. The first two are available from the Formulary, which is where I got mine. I would use them very sparingly and the tests will have to be Trial and Error.

    Also, you might note that the stop bath for ECN2 is dilute Sulfuric Acid. So, the reference you cite is not entirely correct, as I said. And, that is why I referred you to the original by EK first for starters.

    PE

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    Thanks PE! I have benzotriazole, so from what you say, maybe I should do a little trial and error with that and follow the Kodak formula for the amount of Potassium Bromide? Actually, I think the Kodak formula uses NaBr. I have KBr. Maybe the change in amount for the formula I am using is an adjustment for different molecular weight? I guess I will have to figure out what the correct amount of KBr would be, if indeed it is a valid substitute.

    Should the addition of antifoggant affect the overall color balance?

    The other missing ingredient is Kodak anti-calcium no.4. I am using distilled water, hence no calcium, but does this chemical otherwise affect performace, e.g., by affecting pH? Should I try adding a little Calgon, which I have on hand?

    Finally: does the composition of the stop bath affect color balance? I just used a b&w stop bath (acetic acid based) followed by a rinse before bleaching. I do have some sulfuric acid on hand, is that likely to affect color balance?

    I don't mind a little trial and error - I have probably enough ECN-2 stock at this point to last a lifetime.

    And I want to thank you for your comments in this and other threads - you are certainly a wealth of knowledge for which I am very grateful!

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    Also PE, here is a post in which AF-2000 is named:

    http://www.apug.org/forums/archive/i...72922-p-2.html

    It seems from the discussion that it may not do much at all, so its absence may not explain my somewhat green bias. I'm beginning to wonder if the improper stop bath may be more of a cause? And I still have to figure out if Kodak Anti-Cal 4 is a big deal. Kodak's minimum quantities for this are huge and it's quite expensive. The AF-2000 on the other hand is not prohibitive but the minimum is 2x5L - rather a lot.

  7. #7
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    For Antical #4 use either Quadrofos or Sodium Hexameta phosphate. NaBr or KBr can be used as long as one compensates for the molecular weight differences between Na and K.

    Sodium Nitrobenzene sulfonate is an antifoggant, and all antifoggants affect color balance slightly. Each one is different.

    PE

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    OK - thanks - sounds like we have a plan. I will use sodium hexametaphosphate and benzotriazole as I have them on hand, and see what happens! Does the composition of the stop bath affect anything? I guess that's the one outstanding question - I had been using acetic acid instead of sulfuric.

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    What do you mean "we"?

    Anyhow, Sulfuric Acid would not have been used if Acetic Acid was acceptable. There is some benefit from Sulfuric Acid, I am sure, but since the MP product team was separate from the Pro and Consumer projects, I never interacted with them and thus don't know.

    PE

  10. #10

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    Interesting -- you know, the rinse after my acetic stop bath did look a bit pink, almost like there was still some CD-3 in there. Maybe acetic acid just doesn't kill it, but then RA4 stop bath is acetic, isn't it? Carry of developing agent into the ferricyanide bleach might cause a greenish cast, n'est-ce pas?

    I will dig out my sulfuric acid and maybe do a test film tomorrow.

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