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Questions about C41 chemistry and process

Mikey Antonakakis

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Not sure if I should start a new thread, I’d be happy to if this is too off-topic or too old of a thread. I’m looking to clarify a few small details before I start using the Fuji Hunt C41 kit with Jobo CPE2 with Lift.

Question 1, age of kit:
Purchased almost 2 years ago and didn’t open the box until today, stored at 20C the entire time - developer Part C is still a pale clear yellow-ish color so I assume it’s safe to use?

Question 2, mixing and storage of C41 kit:
I plan to use the kit to make 500mL of working solution at a time, breaking up the Developer Part C into individual 10mL glass bottles topped with argon until used to mix new working solution. All other unused chemicals I will plan to store in their original bottles topped with argon. Working solutions will be made with distilled water (from grocery store) and will be stored in amber glass bottles topped with argon, transferred to the Jobo bottles when using, then back to glass/argon when stored. Any issues I am overlooking here, or any further suggestions?

Questions 3+, about process details:
Fuji kit instructions mention doing a preheat - it’s not clear to me if I should do that as a pre-wash? Or just leave the dry/empty drum spinning in contact with the bath water?

Between process steps when using the lift, I’m a little uncertain about timing:
  • Do I start timer as soon as the first of the developer hits the film, or once I finish pouring and all of it hits the film?
  • Instructions with the kit mention “includes 10 seconds drain time” - do I begin the lift at the moment the 3:15 timer goes off, or do I look to finish expelling all the developer when the 3:15 timer goes off?
  • Should I leave the lift up for some time and bump it a few times at the top of the stroke to try to get the last drops of developer down the tubes? Or immediately drop it when developer stops flowing from the discharge tube?
Question 4, to stop or not to stop?:
I know C41 doesn’t specify use of a stop bath, but to get better control of development timing and/or to minimize contamination of the bleach (at least in part due to any remaining developer in the discharge tube), should I use a stop before bleach? Or just pour the bleach straight in? If I stop any recommendation for chemical, or just use water?

Question 5, rinses:
Our tap water is relatively hard, but I have a filter on my temperature-controlled faucet, any issue with using it for the rinse cycles? (I plan to rinse in the CPE2 to help clear the discharge tubing).

Question 6, stabilizer:
I plan to remove film from reels and use a separate tank for stabilizer. I assume using distilled water, one-shot, would be best? Then just hang to dry, or use squeegie? (Would prefer not to squeegie to avoid scratches). I also have a large air compressor and could blow most of the water off…

Question 7, temperature:
I plan to use both the built-in heater and a CineStill sous vide device to heat and circulate the bath water (with jobo temp set a couple degrees lower than the sous vide). I will use my temperature-controlled filtered water tap to fill the bath at roughly 38C to save heating-up time. Also plan to use a digital thermometer as the final say on bath water temperature. I am thinking it would be a good idea to use water to simulate developer temperature loss during the pour process, to calibrate water bath temperature to in-tank temperature. I would probe the tank with a thermometer at the start and finish of a simulated development cycle, and adjust bath temperature to get in-tank average temp as close to 37.8C as possible?

Question 8, bleach and fix times:
As these processes go to completion, I assume there’s no negative impact of running them for a little extra time, especially towards the end of life of 500mL working solution?

Question 9, number of rolls before mixing new batch of chemicals:
Considering I’ll be using ~250mL of the 500mL working solution, and for the time being running either one 120 roll or two 36exp 35mm rolls at time (1520 tank), any reasonable guidelines for total number of rolls of 400 speed film before I make a new batch of working solution? Should I extend times per the Fuji instructions? (I know the proper answer would be “control strips and densitometer,” but I haven’t managed to source a reasonably-priced densitometer yet…)
 
Questions
#1 no worries about age
#2 I've split chemistry, worked, not recommended
#3 Technically no prewash. Practically, using a lift, I have always been concerned about the lift cooling the developer, so I have used a prewash. Nowadays I buy larger quantities of the Developer and use a larger tank than the 1520, use larger volumes of solution. By the book no prewash.
#4 I use stop with RA4 printing, never have with C-41 or E6
#5 Tap water to rinse is standard, keep temperature as close to 38°C as practical.
#6 I do the final rinse solution (Stabilizer) on the reel. Use Distilled water to mix your stabilizer, NEVER a squeegee, 1 minute, hang up to dry no heat.
#7 I just set my Jobo at 38°C. I've been trying to simulate, guesstimate, understand actual developer temperature for decades. I have just decided to be consistent.
#8. Extend bleach and fixer, no problem. Especially if you are getting every bit out of the kit.
#9 Follow the recommended times. I use C41 developer 1 shot these days. I've tried pushing the limit when I was using Tetenal E6 kit (now Adox) I wouldn't recommend it. Follow the instructions. Maximum capacity is easier to attain if you use the mixed chemistry in a week or less.

I'm going to bed, I hope I've helped. I think you're going to do great!
 
Last edited:
Mikey Antonakakis said:
Not sure if I should start a new thread
Click to expand...
Your questions deserve one, IMO. I've split off your post into a new thread.

Insofar as my answers deviate or expand on @mshchem's above:
#2: I personally mix everything and then stored the mixed/working strength developer in glass bottles. Works better that way. The concentrate part C does not contain a preservative. An argon blanket is a mediocre measure to keep air out. The bottle will go bad before the mixed developer will, in general.

#3 w.r.t. timing: I personally always start the timer upon finishing pouring in the developer and stop it as I start to pour it out. So on average is approx. halfway on both steps. It's not as crucial as people sometimes make you think it is, unless you need absolute consistency across multiple batches. In that case a manual process is virtually impossible to dial in perfectly.

#4 I always use a stop. It helps to limit carryover of developer into your bleach, which in a small volume could result in the bleach drifting up in pH, which would cause problems. However, if the bleach is not overused (without replenishment) this will probably not happen. If you re-use your fixer, you really should include one or two wash cycles between bleach and fix as it protects the fixer.

#5 The filter is fine but won't help against drying marks due to hard water. Temperature is non-critical but it's good practice to avoid big temperature transients.

#6 Distilled water is not a stabilizer. If a stabilizer is used, no rinse should be used after it. Modern (Kodak) C41 films do not require a stabilizer. There's a very long thread about 'final rinse/stabilizer' etc. stickied to this forum.

#7 & #8 Agree with above. Don't overthink it.

#9 for the bleach & fixer just do 'whatever' and extend processing times as you see fit. For the developer there's no hard & fast answer because every subsequent roll of developed film will come out differently from the previous one in a re-use system where the developer is not replenished. There's no way around that. Nobody can decide for you at what point the results are no longer acceptable. Most people get 10-20 rolls of C41 from a liter and are fine with it. That is not a guarantee; it says something about how lax quality requirements in the real world often are.

My take on all this has always been: if there's no problem, there's no need to solve it. I.e. give it your best shot and if you're happy with the result, don't worry.
 
Thanks to you both!

#4: do you just use water for fix, or mix in any chemical?

#5 & 6: I am planning to use the filtered tap water for intermediate rinses (between bleach and fixer, and between fixer and stabilizer), and I’ll be using the stabilizer included in the Fuji Hunt kit, mixed with distilled water, as my final rinse.

I did end up running some practice and testing “processing” with water and no film last night, here are my observations for anyone else who might wonder:

Insofar as I have too many thermometers to ever know what temperatures things are , I was able to at least get a decent idea of relative temperature drift through the process: with bath water at e.g. 39.1C, given enough time the in-bottle temperatures (600mL Jobo bottles) was identical to the bath temperature. Didn’t reliably record temperatures on the first practice run, so skipping those results.

On my second round of practice/measurements, I didn’t give enough time for the temps between bottle and bath to fully equalize, so I had a 38.5C reading in-bottle when I started, still with 39.1C bath temperature (measured on the left side of the bath - furthest to the right was nearly 1C lower, but I will keep the developer in the leftmost slot).

After pouring from bottle into a 260mL Jobo beaker (stored immersed in the bath but empty), temp dropped from 38.5C to 38.4C. I then poured the 260mL through the Jobo Lift funnel, and immediately pulled the tank from the rollers to check the “when first poured in-tank temperature” which was 37.9C. Put the tank back and ran the motor for a little over 3 minutes on speed 2, then pulled and checked again, 37.5C.

So, in-tank temperature averaged to roughly 0.8C lower than in-bottle temperature, easy enough to compensate for in practice. The rate at which I ran this practice a few times probably relatively closely mimicked a pre-wash and developer step, with temperatures recorded during the simulated developer step.

Water level in the bath was just touching the side wall of the 1520 tank, I could probably get away with a little greater water level to get a tiny bit more stability at no cost. Seems like the biggest heat sink, unsurprisingly, was the Lift funnel/tubing that is not directly heated by the bath water.

Also worth noting that there remained a few mL of water in the tank after using the lift (even after bonking the lift handle a few times at the top of its stroke), likely from surface tension in the coils of the reel.

I did try the sous vide device, but I don’t think it added much and took up a lot of space/risked falling over and creating a mess. Since I have a temperature-controlled faucet it’s trivial for me to just start with 38C bath water and wait for chemicals to equalize while the built-in CPE2 heater stabilizes the bath temperature.

I will have an opportunity tonight to check my relatively precise/repeatable fast-read digital thermometer against a calibrated thermometer in a medical clinic, so even my accuracy should be pretty good after that. I also managed to find a couple options for +/-0.2C accuracy traceable digital thermometers for under $100, so perhaps I’ll grab one for a little peace of mind.
 
Keep in mind that the lift really makes the Expert drums possible. The smaller tanks, maybe not so well with the short development time of C-41.
 
Mikey Antonakakis said:
#4: do you just use water for fix, or mix in any chemical?
Click to expand...

A stop bath is acidic. I use acetic acid. Other acids can work, too. For some reason, citric acid is not recommended for color processes. I've read once why this is, but frankly, I forgot. Doesn't matter. Acetic acid (e.g. unscented, colorless cleaning vinegar) in dilute form works well; dilution is not critical. Something like cleaning vinegar diluted 1+10 or so works fine. Use once, then discard.

Mikey Antonakakis said:
Also worth noting that there remained a few mL of water in the tank after using the lift (even after bonking the lift handle a few times at the top of its stroke), likely from surface tension in the coils of the reel.
Click to expand...
I don't have a Jobo with a lift, but I've come across multiple problem reports with it. The problems include slow drain times, incomplete draining and the tubing retaining chemistry. This creates problem with esp. carry-over. The lift is convenient, I'm sure, but I'm not so sure whether I would recommend using it esp. for color work.
 
Update:
First development went pretty well! (single roll of 120 Portra 400) Still need to scan to really judge if things were good or not, but at a glance while drying, they are reasonable looking negatives to my amateur eye. (film was also exposed over a year ago so there may be non-development factors at play if they have issues).

I did makes some mistakes that resulted in using the chemicals one-shot, lol. Such as forgetting to swap drain beakers before I poured in my stop - I know that there's a chance some of the chemicals end up in the drain tube when pouring into the Lift, so there's a decent change a few mL of stop solution ended up in the developer, so I tossed it out. Then I got a little overwhelmed/busy trying to do 30-second wash intervals and mistakenly dumped both the bleach and fix down the drain. Good thing I only started with a 500mL batch of working solutions

A couple follow-up questions, I'm guessing the answer is "it's fine" but just want to make sure:
  1. I did a dry/empty preheat with the tank rotating in the bath (about 1/4" or 6mm submerged), ran for about 5min. Then did approximately 45-second warmed prewash. When I dumped it, the prewash water came out dark green-ish. Is that normal? (anti-halation dyes or something?). And does that seem like the right amount of time for a pre-wash/soak (I figured better to not overwash)?
  2. When I dumped the developer, it also came out quite strongly colored (red-brown? I was tired, memory is fuzzy). Same question, that's normal, yes?
  3. There was still a little reddish-pink color (again, a little fuzzy on the color) following the post-bleach washing. Did 7 or 8 fill/drain cycles as close to 30s intervals as I could manage, tank rotating for the duration.
  4. Post-fix wash I ran some extra cycles, ran for at least an additional minute (over the prescribed 3:15 second wash step in the Fuji Hunt instructions). Following the 9th or 10th final drain/fill cycle, there was still a very slight pinkish coloration to the wash water.
  5. I ran the stabilizer in-tank wtih film still on the reel and cap removed, for 80 seconds. Gently filled, tapped, the bubbles free, and then let it sit for the duration. Again, very slight pink color when I dumped the stabilizer.
 
Last edited:
Mikey Antonakakis said:
the prewash water came out dark green-ish. Is that normal? (anti-halation dyes or something?)
Click to expand...
Yes, correct. Mostly anti-halation dyes.
Pre-wash time is not critical but I wouldn't leave it for many minutes, let alone longer. Your 45 sec sounds fine to me. Mind you, a prewash is not obligatory, but personally I find it a good idea on a Jobo with 120 roll film or sheet film as it avoids (in my case) uneven development.

2: yes, also normal. This is mostly due to the magenta dyes that are there for...well IDK really, could be in part filter dyes, or acutance dyes, or...
3 & 4 & 5: ...and yes, those magenta dyes are very persistent and they basically keep washing out of the film; there's virtually no end to it. Don't worry about it.
 

Awesome, thanks for all the help! I'll come back with a scan or two at some point
 

Mikey Antonakakis said:
Question 1, age of kit:
Purchased almost 2 years ago and didn’t open the box until today, stored at 20C the entire time - developer Part C is still a pale clear yellow-ish color so I assume it’s safe to use?
Click to expand...
Have you opened the package? If not, it is probably ok. If so, you can only find out by using it.

Question 2, mixing and storage of C41 kit:
Distilled water is only needed if there is a problem with the tap water. Most people will not have a problem. I would mix all the chemicals and use within three or four days.

Yes follow the instructions including heating the pre-wash. There is no need to temperature shock the film.
Retired and long passed Photoengineer, PE, recommended using stop bath. I never have needed to.
Mikey Antonakakis said:
Question 5, rinses:
Our tap water is relatively hard, but I have a filter on my temperature-controlled faucet, any issue with using it for the rinse cycles? (I plan to rinse in the CPE2 to help clear the discharge tubing).
Click to expand...
I would not expect any.
Hang the film and then use a paper towel touched to the bottom corners of the film to draw off any excess water.
Get as close to the direction specified temperature as you can do.
Mikey Antonakakis said:
Question 8, bleach and fix times:
As these processes go to completion, I assume there’s no negative impact of running them for a little extra time, especially towards the end of life of 500mL working solution?
Click to expand...
Stick to the instructions unless you need to make a change.
MIx all the chemicals and have enough rolls of film to process in three or four days.
 
Those people who are blessed with pure mountain snow melt for water, SG. Tap is fine. For the rest of us it's hit or miss. Depending on bedrock, I have to use purified water for things like XTOL developer otherwise it won't fully dissolve.
 
mshchem said:
Those people who are blessed with pure mountain snow melt for water, SG. Tap is fine. For the rest of us it's hit or miss. Depending on bedrock, I have to use purified water for things like XTOL developer otherwise it won't fully dissolve.
Click to expand...

My tap water is from the Owens Valley in the eastern California and the Colorado river.
 
mshchem said:
Isn't that where the water war was fought? (Owens Valley) I've probably been watching too many PBS documentaries
Click to expand...

War? No, outright theft. But Mark Twain said "In California whiskey is for drinking but water is for fighting.
 
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