RA-4 developer homebrew critique

Discussion in 'Color: Film, Paper, and Chemistry' started by newcan1, Jul 8, 2013.

  1. newcan1

    newcan1 Subscriber

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    I've been using the following formula as an RA4 developer (found on http://www.bonavolta.ch/hobby/en/photo/c41_ra4_chemicals.htm):

    Water (Room Temp) 750.0ml
    Triethanolamine 6.0ml
    Sodium Sulfite, Anh. 1.0g
    CD-3 5.0g
    Potassium Carbonate 40.0g
    Sodium Chloride 0.5g
    Tinopal SFP 0.5g
    Water to make 1.0L

    Except I use a different (Sprint Systems) or no brightener, Tinopal not being available to me.

    I find that while this formula is apparently designed to use at 95 deg F for 1 minute, it seems to work best at 100 deg for 1.5 minutes, leaving me to wonder whether the formula can be improved. Any suggestions? I thought of maybe boosting the CD3 a bit as that has produced results in other areas (eg., small tank processing of ECN-2), but otherwise, I'm at a loss. I like to mix my own chems as it is convenient and extremely economical. Any suggestions/comments on the above formula or alternative homebrew RA4 formulae would be gratefully received.
     
  2. Rudeofus

    Rudeofus Subscriber

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    This formula (correct link here) does not list a pH value which makes its activity more or less a random guess. The author even states that Hydroxide can be added to make it more active, so that's the first thing I would try with this formula ...
     
  3. newcan1

    newcan1 Subscriber

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    Hi I have also found an earlier APUG thread discussing this formula, which suggested the pH was too high and also that by reducing the amount of sulfite, the activity of the developer could be increased. So I am playing around with the formula now and should see soon what any changes in results happen to be.
     
  4. RPC

    RPC Member

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    I believe I started the thread you are referring to and I have since tried it with Fuji CAII paper as well as Endura and found that by lowering the carbonate to 30 grams no pH adjustment is necessary (keep sulfite at .2 grams) and it works well with both papers, normal contrast with no crossover. In fact, I normally prefer it over the Kodak RA-RT developer, although I still use both. Use at 68 F for two minutes. Mix with distilled water. I don't know how it will perform at high temperatures. Contrast can be controlled by altering the amount of carbonate but watch for crossover. It is odor free but has a life of only days. I mix it as I need it. Also, it has no tar preventing chemicals so expect a little build-up. Most can be removed with alcohol.
     
  5. newcan1

    newcan1 Subscriber

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    Hi RPC, well I took your comments from the prior thread on board, and this is what I did: Using Sodium Carbonate instead of Potassium Carbonate (the original formula would have required 31g sod. carb) I reduced the amount to 25g. I increased the CD3 to 5.5g. And I reduced sulfite to 0.2g. Developing for 1 min at 97 degrees, the results with Ektacolor Edge seemed very good indeed. The pH was 10.4 or so, but my meter may read a bit high.
     
  6. RPC

    RPC Member

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    Glad it is working for you. I have been using this developer when I need normal contrast with the Fuji paper. To me, the Kodak developer is a bit too contrasty for people pictures/skin tones with this paper.
     
  7. newcan1

    newcan1 Subscriber

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    Well I would like to be able to increase contrast to print with ECN-2 negatives. It seems to me that reducing the carbonate has increased contrast a bit, or should that be the other way around? Maybe it was the slight increase in CD3. I may go to 6g/L CD3 and see what happens.

    I can increase contrast a lot by adding H2o2 but want to perfect the basic formula first.
     
  8. RPC

    RPC Member

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    The contrast should increase if you increase the carbonate. The increase you experienced might be to do with using sodium carbonate and/or the paper you are using. To increase more, try adding 5 or 10 grams of the carbonate. That should do it but if you observe unacceptable crossover then give H202 a try.
     
  9. newcan1

    newcan1 Subscriber

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    Would the contrast have been increased by reducing the sulfite from 1g/L to 0.2g/L?
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    The pH is critical and should be about 10.5. The additional secret is the use of Lithium salts and and a Sulfonic acid. These changes were needed to offset the removal of Benzyl Alcohol and improve development rate.

    So, IMHO, none of the internet formulas are correct so far. If I can find one, I'll post it here someday.

    PE
     
  11. RPC

    RPC Member

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    Yes, that is why I reduced it. The contrast was too low with 1 g. You might try no sulfite, but shelf life would be even less.
     
  12. RPC

    RPC Member

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    Qualitywise, this developer is very good and works superbly with Fuji CAII paper and Endura paper. Its only downside as I mentioned earlier is tar (I get a stain in my trays), and short shelf life. I have seen the formula by Steven Keirstead, which no doubt solves these problems, but in my opinion is too complex and probably is not worth the trouble for the typical home user, considering the image quality of this developer.
     
  13. newcan1

    newcan1 Subscriber

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    I use drums and they are washed between each use so I dont think tar is a problem for me. I agree, the developer as tweaked seems very good, and the other formula does involve some expensive/hard to source chemicals.

    I am about to use up my liter of "tweaked" developer, and will make up another batch with the original amount of carbonate and maybe 6g CD3, and see what happens. I want to end up with one formula optimized for general use, and one for printing ECN-2 negatives.

    Reflectin on PE's comment that you posted above -- I wonder what would happen if one were to take out triethanolamine and replace it with benzyl alcohol?
     
  14. Photo Engineer

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    The RA4 developer uses Hydroxyl Amine Oxalate to prevent stain and tar and to help reserve the developer. You can substitute Hydroxyl Amine Sulfate with the correct adjustment in amount. The recommended brightener is chosen to prevent yellowing with keeping. Some brighteners yellow heavily with age.

    PE
     
  15. RPC

    RPC Member

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    Thanks. I will try it sometime.
     
  16. Rudeofus

    Rudeofus Subscriber

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    Triethanolamine is a strong alkali while Benzylalcohol isn't, so you will have to adjust pH if you really want to avoid Triethanolamine.
     
  17. newcan1

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    PE indicates that HAS can be used as a preservative.....is that all it does? The formula we have been discussing works pretty well, and now I'm wondering what would happen in the context of C41 developer if HAS were omitted? Because it's one of the more expensive ingredients.
     
  18. Rudeofus

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    AFAIK it is used as a preservative. It is also quite acidic, so be prepared for strong pH adjustments after adding it to your recipe. Unlike Sulfite, it doesn't react with oxidized developer which means it doesn't prevent the dye coupler reaction we need for color processes.
     
  19. RPC

    RPC Member

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    I have tried C-41 developer without HAS and with pH adjustment seemed to work well, but one would expect a shorter shelf life.
     
  20. newcan1

    newcan1 Subscriber

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    What did you use for the pH adjustment? More carbonate?
     
  21. RPC

    RPC Member

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    After mixing the formula the pH is too high, even without HAS, so I just add whatever acetic acid I need to bring it to normal.
     
  22. Photo Engineer

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    The standard procedure to adjust pH is to use Sodium Hydroxide or Sulfuric Acid depending on the direction you want to move. Neither developer (C41 or RA4) should contain Benzyl Alcohol. HAS extends shelf life and also it prevents tar formation and it helps keep Dmin low.

    PE
     
  23. newcan1

    newcan1 Subscriber

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    By the way -- what is the purpose of potassium (or sodium) chloride in the formula? And if the formula calls for sodium chloride, how much potassium chloride should be used in substitution?
     
  24. Photo Engineer

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    The color paper emulsions are mainly AgCl emulsions and thus Cl ion acts as a seasoning agent and restrainer or antifoggant. The positive ion balance (Na or K) is probably important for balancing development, but I am not sure.

    PE