E-6 and C-41 Processing for Beginners

[Nick Zentena]

PE which part? I just use the C-41 developer which I understand runs a little hot. For me it doesn't make sense to bother with home mixing C-41 fix or bleach. The mini-lab jugs are so cheap and the concentrates keep well enough.

 

[Photo Engineer]

The developer is lacking Iodide, the blix is nearly useless for film, and the blix and bleach lack sulfite which is needed to prevent colorations from forming from carryover of oxidized developer.

There is another site here which has much better formulas, and has been posted here.

For obvious reasons, I don't need those formulas for myself. So, I have not bookmarked the URLs. Sorry.

PE

 

[entmas]

There are several URLs posted here and on PN with chemical formulas. The E6 formulas that I have seen are further from the correct ones than the C41 and RA formulas, and so work a bit differently, but they are serviceable.

PE

Thanks, Everyone,

Before I posted my question, I had researched the web for the recipes and found most of them that had been referenced here and elsewhere. I also researched the cost and availability from various sources. My confusion, or actually a wish to know, is about the benefits one vs the other and all of them vs the commercially available Kodak items.

Also, some recipes I had found here include liquids, yet the give the dosage is in weight units (or vice versa). So I researched the specific gravities of such components and converted them to volumes. Yet I am not sure that there had not been an error in the postings.

Some formulas identified the final pH values needed. But, I want to know how I would control the pH, given that the formulas are quite precise. What ingredient is to be added in order to increase and what ingredient is to be added to decrease pH? How such an additive would affect the processing of the film in C-41? This I could not find on the web. If this discovery is to be done by trial an error on my error, it is like reinventing a wheel. These formulas have been available for a long time, so I have hoped to learn from someone's experience.

I also want to learn about the mixing techniques. Do I use a mixing spoon and swirl slowly or quickly, and for how long? Or do I mix in a amber glass bottle and mix by shaking and inverting? Do I mix all ingredients at once or one at a time? Do I mix the solutions at constant temperature, which I can do quite accurately (+/- .1 degree C) as long as the temperature is above ambient by no less then 5 degree C, or does the mixing tolerant enough to the fluctuations in temperatures during mixing and in the ambient?

What else do I need to know that comes from from experience or research?

The suggestion that I pre-mix bleach and fix is not really an option for me. I live in NYC and the space is just not available. The fewer liquids and the smaller containers I store the better off I am (if I want to do the darkroom and keep my marriage, and I do).

So where do I find answers to my questions?

Michael

 

[Photo Engineer]

Michael;

Here are some answers, without having specifics about the liquid and weigh issues. When mixing use gentle stirring and try not to overly aerate the solutions. Add sulfite to developers first before any ingredients, and then hydroxyl amine or any of its derivatives to prevent oxidation.

To adjust pH, it is always safe to use sodium carbonate, sodium bicarbonate, sodium hydroxide or dilute sulfuric acid for developers. Never use hydrochloric acid or nitric acid or even acetic acid in developers.

For blixes and fixes, use 28% acetic acid or ammonium hydroxide to adjust pH.

Is this of use in answering some of your questions?

You should not need density to adjust weight/volume figures. If you post a specific formula, I'll try to help.

PE

 

[entmas]

PE,

Here are the formulas that I have found and after reading comment on various sites I have decided to use, unless I am advised otherwise (all to make 1 L):

C-41 Developer:
Water (total) 949.898 g
Potassium Carbonate anh. 37.500 g
Sodium Sulfite anh 4.300 g
Hydroxylamine Sulfate 2.000 g
Postassium Bromide 1.500 g
Potassium Iodide 0.002 g
CD-4 4.800 g
Resulting pH 10 < pH < 11

What worries me in the above formula are the following points:
1. Sequence of mixing
2. The weights add to 1 KG, which the density of water at 4 degrees C. But given the precision of the ingredients required that may not add up to 1 liter, unless each ingredient does not dissolve but produce a mixture and displaces water to produce the volume of 1 L. On the other hand, this may be immaterial and I should not worry about it.
3. If the formula is that precise, why the pH level is given in a range? Would it not be a constant? What is the pH a function of that can deviate its level? Is the pH level the only control output variable that I need to watch and adjust? Would adjusting the pH level change the chemistry of the developer, if after mixing in all ingredients accurately, the pH level is outside the range?
4. Do I mix the formula at room temperature or at, say, 30 degrees C for better solubility?
5. How long do I need to do the mixing of each component?
6. What does it mean not to "overly aerate"? What kind of beaker do I need to use so that I will not overly aerate the solution? Or what technique of mixing do I need to practice to minimize aeration?
7. Do I split the water volume, as another similar formula has it, into the original amount of 800 ml as the starting point and then add whatever volume is necessary to make 1 L?

Bleach

Water 750.000 mL
Potassium Ferricyanide 80.000 g
Ptassium Bromide 20.000 g
Water to make 1 L

I do not generally have questions about this formula for bleach, except those above that relate to mixing techniques and temperature.

But, do I also need to worry about the aeration? Do I need to worry about the pH level and how would I control it here?

Fix

Water 750.000 ml
Ammonium Thiosulfate, 60% 160.000 ml
EDTA (acid granules) 1.000 g
Sodium Bisulfate 12.000 g
Sodium Hydroxide 2.500 g
Water to make 1 L

Again, this formula just for bleach gives me enough latitude to produce 1 L of fixer by controlling the water at the end. But the same questions as above apply as to the sequence, technique, aeration, and pH.


Stabilizer

Water 994.000 ml
Formaldehide (37% Solution) 5.000 ml
Kodak Photoflo 1.000 ml

My questions here are the same as above about the splitting of water for the beginning and the end, sequence, technique, aeration, and pH.

The process schedule is the following:

Developer 3:15 @ 37.8 deg C
Stop Bath :45 @ 37.8 deg C
Water Wash :30 @ 37.8 deg C
Bleach 2:30 @ 35.5 deg C
Water Wash 1:00 @ 35.5 deg C
Water Wash 1:00 @ 35.5 deg C
Fixer 6:00 @ 35.5 deg C
Water Wash 2:00 @ 35.5 deg C
Water Wash 2:00 @ 35.5 deg C
Stabilizer 2:00 @ 23.9 deg C

PE, would you comment on the process as well?

Thanks,

Michael

 

[PHOTOTONE]

In regards to temperature control of E-6 and C-41, the goal (as I see it) is to have an "average" temperature within 1/4 degree of accuracy. Thus, by testing, one can start out with a slightly higher temperature of the first developer, and over the course of the processing step the developer temperature drops, and thus achieves an "average" temperature of within 1/4 degree if ideal. All solutions will drop some in temperature, even if in a tempering bath when you introduce the rolls or sheets of film on metal reels or film hangars that are at room temperature. The severity of this drop depends on the number of reels or hangers, and the quantity of developer being used. I always start out a teeny bit "high" on my first developer temperature in my 3.5 gallon sink-line for dip-n-dunk style processing.

In regards comments from previous posts saying that good results have been achieved even with wider temperatures than considered OK. It is a fact that one can get visually acceptable slides with a process that is operated out of control standards, but they will not be "neutral" and some types of subject material will have a color cast. It all depends on what you want to expect from your processing.

 

[Photo Engineer]

Everything looks good to me, but the bleach is ferricyanide, and C41 uses a Ferric EDTA bromide bleach. You can use ferricyanide, but the stop is mandatory and I would make it 2% acetic acid plus some sulfite to scavenge developer, and I would use a longer wash after the stop, say 2 minutes, before bleaching.

The developer should not use water in gravimetric measure, and should have an exact pH value. I believe it is 10.5 at 20 C, but the mixing order is fine as given. The CD4 should go in last, or it should go in at least after the sulfite and hydroxyl amine sulfate. I personally would use the same order, but would put the carbonate in last. That is what I'm used to.

So, you should start with 800 ml of water at about 90F, and add everything in that order but the carbonate. Add carbonate last, then adjust pH to 10.5 at 20 deg C.

PE

 

[entmas]

I have another question that relates to stabilizer. A close relative of mine who was, according to him, an excellent developer and printer of B&W, color negs and positives told past Friday that I must not (that strong!) use stabilizer. Instead, I should take the reels out of the drum and dip them into the Photoflo bath and immediately take out. Then, shake the excess liquid off and hang them the films to dry.

His rationale was that the stabilizer may (and will) produce water and formaldehyde streaks and stains. His close friend, who had photographed some very famous people, and whose films my relative had developed, has all my relative's negs survived in excellent shape for some 20 years.

In all the web postings, I see the stabilizer being used in the C-41 process (for different times, albeit).

Would you please comment on eliminating the stabilizer.

Thank you.

Michael

 

[Photo Engineer]

Michael;

I have commented and commented until I'm tired of this particular subject.

Stabilzers or Final Rinse solutions are necessary for the best keeping of color materials. There are no qualifications to that in any of the Kodak or Fuji guidelines. The formalin in older stabilzers and the organic compound in the newer Final Rinse do 'good things' to color dye images and film.

PE

 

[entmas]

Thanks!!!

Michael

 

[Nick Zentena]

The developer is lacking Iodide, the blix is nearly useless for film, and the blix and bleach lack sulfite which is needed to prevent colorations from forming from carryover of oxidized developer.

I forget what Iodine does. Restrainer?

Personally I use Fuji Bleach that I got a great deal on. The stuff will last me a couple of decades Too bad it'll likely go bad long before that.

 

[Photo Engineer]

Iodide is both a restrainer and buffer for edge effect in this developer.

PE

 

[entmas]

PE,
Another couple of questions:

1. A question about Acetic Acid 2%.

If I get 99.5% acid from B&H (which is Photographers Formulary's but a few bucks cheaper) do I just dilute it in water or in something else? (A assume that at 99.5% concentration, I would need 25 ml of acid and 975 ml of water (is this correct?)

2. Question about a sulfite additive to the 2% acetic acid.
What kind of sulfite would you recommend and how much of it do I need to add to 2% acetic acid solution?

Michael

 

[entmas]

I think I made a mistake in ratios to mix 2% Acetic Acid:
for 99.5% Acetic Acid Glatial the mixing ratio is 20.1 ml to 979.9 ml of H2O but for 80% acid the ratio is 25 ml to 975 ml.

Would you verify that?

 

[Photo Engineer]

PE,
Another couple of questions:

1. A question about Acetic Acid 2%.

If I get 99.5% acid from B&H (which is Photographers Formulary's but a few bucks cheaper) do I just dilute it in water or in something else? (A assume that at 99.5% concentration, I would need 25 ml of acid and 975 ml of water (is this correct?)

2. Question about a sulfite additive to the 2% acetic acid.
What kind of sulfite would you recommend and how much of it do I need to add to 2% acetic acid solution?

Michael

Michael;

If you use ferricyanide as a bleach in color processes, you need a clearing bath with 2% acetic acid. I round it and use 20 ml in 980, as that is close enough.

I would say that about 2 - 5 g/l of sodium sulfite would be enough, but I don't know how well it would work. I never used a ferricyanide bleach with the final C41 process as the system was not designed to work that way. I just know that you need one. Color developer carried into the ferricyanide bath will oxidize, but the sulfite prevents that. Once oxidized it can couple and give you stains.

You can probably find one in old books or formularies. Just look for clearing baths. That would be more nearly what you want.

PE

 

[entmas]

PE
Thanks for your last reply.

On the Photoflow: Can it be substituted for Edwal LFN in the stabilizer for C-41 or is only for B&W films?

 

[Photo Engineer]

Any wetting agent can be used, not just photo flo. It is the stabilizing agent that is necessary, and the newest one is proprietary avialable only from Kodak or Fuji. Otherwise, you have to be satisfied with formaldehyde.

PE

 

[entmas]

PE,
Thanks again for your advice above.

Sorry to bother you, but I have no other source of information that I can fully trust. I wonder if you could advise on the use of a lab magnetic stirrer for mixing chemicals (as you may recall, I do not anticipate mixing more then 1 L at a time)? Would they help in preventing some aeration that you mentioned above if I spin the stirring magnet at, say, 1 rev per second. Or would you say that that is too fast and I would need to run it much slower speeds so that the vortex would not suck up more air than advisable? Or would you say that manual stirring is the best?

I understand that some chemicals in the C-41 type formulas are not very soluble. What would your recommendation be for the stirring times of individual components?

I was told that I should let the mixed solutions sit for a couple of hours to ensure their better homogeneity before I start the film development. Would please also comment on that?

Thanks !

 

[dslater]

PE,
it is my understanding that Kodak's latest E-6 home process kit has moved the stabilizer from the final rinse to the pre-bleach step. Given that, is the final rinse nothing more than a wetting agent?

Also, how well do the C41 and E6 final rinses keep once mixed?

 

[Photo Engineer]

Two answers;

1. You can use most any stirrer. Just don't run it at high speed.

2. E6 appears to have two stabilizers. I'm not sure as it was changed after I retired.

PE

 

[dslater]

PE,
Thanks for the reply - the reason I asked about the keeping properties of the final rinses is that I don't do enough processing to mix up whole batches of C41 or E6 - I just mix what I need - this seems to work fine for me - only thing is that the final rinse concentrates have a very small volume. I was thinking I might be able to just mix up the entire quantity of final rinse and store it.

 

[Photo Engineer]

Oh, the final rinse will keep just about forever. It may eventually grow mold or bacteria unless you use distilled water. But OTOH, it is a bacteriostat.

PE

 

[Randy Stewart]

PE,
Thanks again for your advice above.

Sorry to bother you, but I have no other source of information that I can fully trust. I wonder if you could advise on the use of a lab magnetic stirrer for mixing chemicals (as you may recall, I do not anticipate mixing more then 1 L at a time)? Would they help in preventing some aeration that you mentioned above if I spin the stirring magnet at, say, 1 rev per second. Or would you say that that is too fast and I would need to run it much slower speeds so that the vortex would not suck up more air than advisable? Or would you say that manual stirring is the best?

I understand that some chemicals in the C-41 type formulas are not very soluble. What would your recommendation be for the stirring times of individual components?

I was told that I should let the mixed solutions sit for a couple of hours to ensure their better homogeneity before I start the film development. Would please also comment on that?

Thanks !

1. The speed you would require of your mixer is dependant on the following factors: volume of solution, weight of solution [how much chemical is already in solution], shape of container; shape of mixing rod. So, there is no ideal revolution speed. You want it to stir fast enough to put all unsolved material into the mixing process [not stuck on the bottom of the beaker] and slow enough not to create turbulance which whips air into the solution [which is pretty obvious when it happens]. Magnetic stirring beats hand mixing every time.

2. Stirring time: Until everything dissolves!

3. Better homogeneity through standing a few hours? Not hardly. In some formulas, there is a chemical interaction required which occurs between the individual components once dissolved to produce a by-product which is the desired chemical component. This process may or may not take some time. Unless you find a specific warning in your instructions to delay initial use of your particular solution, forget it.

 

[Photo Engineer]

Randy;

Your answer is very complex. Just stir until dissolved at a speed that does not whip air into it. A moderate vortex is enough.

There are no interactions that I know of that are required in any color chemistry on the market by Kodak. Order of addition is important though to prevent over oxidation, therefore that is a must for all developers.

PE

 

[entmas]

Thank you PE and Randy for answering my questions

Michael