RA-4 developer homebrew critique

newcan1 · Jul 8, 2013

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.

Rudeofus · Jul 8, 2013

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 ...

newcan1 · Jul 8, 2013

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.

RPC · Jul 8, 2013

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.

newcan1 · Jul 8, 2013

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.

RPC · Jul 9, 2013

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.

newcan1 · Jul 9, 2013

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.

RPC · Jul 9, 2013

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.

newcan1 · Jul 9, 2013

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

Photo Engineer · Jul 9, 2013

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

RPC · Jul 9, 2013

newcan1 said:
Would the contrast have been increased by reducing the sulfite from 1g/L to 0.2g/L?

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.

RPC · Jul 9, 2013

Photo Engineer said:
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

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.

newcan1 · Jul 9, 2013

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?

Photo Engineer · Jul 9, 2013

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

RPC · Jul 9, 2013

Photo Engineer said:
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.
PE

Thanks. I will try it sometime.

Rudeofus · Jul 10, 2013

newcan1 said:
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?

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

newcan1 · Jul 10, 2013

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.

Rudeofus · Jul 10, 2013

newcan1 said:
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.

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.

RPC · Jul 10, 2013

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

newcan1 · Jul 10, 2013

What did you use for the pH adjustment? More carbonate?

RPC · Jul 10, 2013

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.

Photo Engineer · Jul 10, 2013

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

newcan1 · Jul 22, 2013

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?

Photo Engineer · Jul 22, 2013

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

RA-4 developer homebrew critique

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