Preserving working or opened solution of developer and other C-41 chemistry for several months

ymc226 · Mar 13, 2023

Just about to start developing color and read that the developer goes bad in several weeks after mixing from concentrate (working solution). The left over concentrate also goes bad but not as quickly after opening the bottles (1-2 months). I ordered the 1 quart Arista C-41 kit which is good for 8 rolls of film so no need to "store" the chemicals as I would process at least 8 rolls at a time via my soon to arrive Filmomat.

Looking at the Freestyle site for C-41 developers, there are options for larger kits up to 5L (Rollei). If I measure out these larger kits to mix up 500ml working developer solution at a time (enough for 4 rolls of 135 or 120), can I use the gas displacement method (storing in original bottles) or store the remaining concentrates in cleaned wine bottles with the Vacu Vin? I anticipate it would take up to 4 or 5 months to work through all the concentrates.

Also, if I completely mix the three parts of Blix and Stabilizer to working solution strengths (all 5L), do these 2 chemicals last the 4 to 5 months I anticipate?

It seems like a lot of effort, maybe, just buy the quart or liter kits would be less of a hassle.

mshchem · Mar 13, 2023

Use pure water that has been sitting at least a week. There's a lot of air in tap water.

Mixed developer stores great in a very low oxygen environment.

The fixer (concentrate) part of blix (clear liquid) is basically regular rapid fixer. Keeps fine at room temperature in full bottles, exclude air, to prevent sulfur formation

The bleach part of blix will keep forever

Keep bottles as full possible

I would invest in a bunch of nice glass and PET bottles with polyseal cone seal lids.

Inert gas purges work great, don't skimp on the gas.

Tel · Mar 13, 2023

My experience may not relate directly to your plans, but might help you with your calculations anyway. I've only used a liquid kit once; I prefer the dry powder kits because of their long shelf life. I use the Unicolor 1L kits, typically buying them in lots of four or five and storing unopened ones for up to a couple of years. I have four 500mL brown glass bottles with screw-caps that I use exclusively for C-41. I mix up a liter of working solution and divide that in half, filling two 500mL bottles with dev and two with blix. I store them on a shelf in a cabinet in my kitchen (no refrigeration). Each half-liter typically gives me 8-10 rolls. The unopened bottles keep for a long time: I just hit roll 16 for a liter that I mixed on October 6. It was looking quite clear and probably was good for more, but I have a rule that I arbitrarily follow, to dump each pair of bottles after 8 rolls even if it looks good to go for more. I found in the past that C-41 tends to fall off a cliff when it does fail and I don't like to risk that.

I will say that temperature may be a factor in longevity. I typically get 5-6 months out of batches that I mix in the winter, slightly less in the summer. I've used Tetenal liquid but mostly prefer the Unicolor powder kits, which are often rebranded by other sellers, possibly freestyle and almost certainly FPP. The only time I had these powder kits fail before mixing was when the envelope they came in had a broken seal.

And a footnote: you don't need the stabilizer at all.

Xylo · Mar 13, 2023

The thing with C-41 is that as it ages, it affects color saturation and density.
When they say that it's good for only a few weeks and a few rolls, it means that you will get consistent results for that number of rolls during that period of time. But after that, it usually doesn't die of a sudden death like Xtol. You will still get results that are OK for scanning. If you do RA-4 printing, then you probably want to avoid overworking the chemicals. If you do, the filter pack you usually use will be useless and you will need to re-calibrate. Easy with a color analyzer, not so easy with test strips.

For the chemicals, I tend to like the 1 liter powder kits. Cheap and not heartbreaking if I don't use them to their fullest.

I have a kit that I diluted on the 4th of July last year and that I'm trying to figure out how long it will stay usable. Since I don't care about exact colorimetry, I'm not picky when it comes down to the results. I just do a leader test of all the chemicals before I start developing to make sure it will work.

For preparing the chemicals, I used spring water (distilled would be better). I store them in glass bottles with a good seal. I also fill the bottles with some air-in-a-can. The trick is to blow some gas in the bottle until the sound the gas rushing in stops changing. Store the chemicals in a cool place.

I know a guy in the UK who managed to pull close to 100 rolls through some chemistry and kept the chems for over a year. Granted the final roll was pretty ugly by any standard, but it did work to some extent. But I definitely wouldn't go as far as he did...

mshchem · Mar 13, 2023

If you are spending so much money on the Filmomat I would continue to buy 1 L kits until you get an idea of what you need. Another thing is waste disposal, you don't want to have expired chemistry to deal with.

Powdered chemistry does store forever.

ymc226 · Mar 13, 2023

mshchem said:
Use pure water that has been sitting at least a week. There's a lot of air in tap water.

Great, I bought many gallons of distilled water that have sat for weeks/months.

mshchem said:
Mixed developer stores great in a very low oxygen environment.

The fixer (concentrate) part of blix (clear liquid) is basically regular rapid fixer. Keeps fine at room temperature in full bottles, exclude air, to prevent sulfur formation

So I can't mix the complete kit of Blix at the beginning and expect it to keep for 5 months.

mshchem said:
The bleach part of blix will keep forever

Keep bottles as full possible

I would invest in a bunch of nice glass and PET bottles with polyseal cone seal lids.

Inert gas purges work great, don't skimp on the gas.

Thanks for the advice.

ymc226 · Mar 13, 2023

Tel said:
My experience may not relate directly to your plans, but might help you with your calculations anyway. I've only used a liquid kit once; I prefer the dry powder kits because of their long shelf life. I use the Unicolor 1L kits, typically buying them in lots of four or five and storing unopened ones for up to a couple of years. I have four 500mL brown glass bottles with screw-caps that I use exclusively for C-41. I mix up a liter of working solution and divide that in half, filling two 500mL bottles with dev and two with blix. I store them on a shelf in a cabinet in my kitchen (no refrigeration). Each half-liter typically gives me 8-10 rolls. The unopened bottles keep for a long time: I just hit roll 16 for a liter that I mixed on October 6. It was looking quite clear and probably was good for more, but I have a rule that I arbitrarily follow, to dump each pair of bottles after 8 rolls even if it looks good to go for more. I found in the past that C-41 tends to fall off a cliff when it does fail and I don't like to risk that.

I will say that temperature may be a factor in longevity. I typically get 5-6 months out of batches that I mix in the winter, slightly less in the summer. I've used Tetenal liquid but mostly prefer the Unicolor powder kits, which are often rebranded by other sellers, possibly freestyle and almost certainly FPP. The only time I had these powder kits fail before mixing was when the envelope they came in had a broken seal.

And a footnote: you don't need the stabilizer at all.

Thank you. I thought of using the powder kit as well and like your plan. I would only mix up when I have at least 8 rolls to develop so would need only 2 glass bottles. Also, in order to maximize the freshness for several months a gas product may be used as well. I will have to see if the Filmomat requires a little more than the 500cc to fill the development tank just so it does not suck any air into the system.

I've never done color before. Why don't you think stabilizer is needed? If not, it would simplify things more. The only color films I am using (120 and 135) are Kodak Portra 160 and 400.

ymc226 · Mar 13, 2023

mshchem said:
If you are spending so much money on the Filmomat I would continue to buy 1 L kits until you get an idea of what you need. Another thing is waste disposal, you don't want to have expired chemistry to deal with.

Powdered chemistry does store forever.

You may be right. No need to make thinks so complicated. I may get the powder kits after I use up the 2 Arista kits I have.

I'm not sure if anyone can answer this but the Rollei kit I referred to in my initial post is the only kit with a different capacity compared to most of the other kits which presume 8 rolls/500cc. The Rollei seems to allow twice, 16 rolls/500cc if I am reading the instructions correctly.

mshchem · Mar 14, 2023

I don't have any idea what the "Rollei" kit is. Like much of this stuff, that's just a brand that someone has licensed, again never used it. The powder comes by many different names, I suspect most comes from the same people. Arista (Freestyle) has a great reputation, traditional educational supplier. I have always used Kodak Flexicolor chemistry, but with the pandemic mess, the Kodak color chemistry has been made in China for many years. I would stick with the Arista stuff for your first few dozen rolls.

MHOFWIW

mshchem · Mar 14, 2023

Rollei chemistry made in Germany, looks like claim is upto 16 rolls per liter. I wouldn't take it that far. Instructions look like Tetenal, made in Germany, good stuff. Tetenal announced recently that they are looking for a new manufacturing site. So that stinks. Hopefully that will be worked out soon.

Freestyle has a stable supply, I think, of their Arista brand of chemistry.

ymc226 · Mar 14, 2023

Thanks mshchem for the thoughts. I now remember when I used to do my own B&W processing, I kept track of all the chemical use and expiry times as well. Also, used the accordion type bottles that minimized extra volume and the Vacu Vin to seal wine bottles for storage preservation.

Maybe keeping it simple will make the entire process more enjoyable. Arista is likely rebranded Cinestill who also makes a 500ml kit that would be one shot use for 4 rolls, and would need no storage considerations. Now after everyone’s advice, which has helped a lot, and is why I find Photrio so valuable, I may go completely in the opposite direction.

Mr Bill · Mar 14, 2023

ymc226 said:
I'm not sure if anyone can answer this but the Rollei kit I referred to in my initial post is the only kit with a different capacity compared to most of the other kits which presume 8 rolls/500cc. The Rollei seems to allow twice, 16 rolls/500cc if I am reading the instructions correctly.

C-41 developers are fundamentally all the same, as mixed in the processing tank. Meaning that the concentration of the developing agent and the restrainers (which are typical byproducts of development) are gonna be nearly identical no matter the manufacturer. And these are gonna be the primary things affecting the "activity" of the developer.

When you develop film a certain amount of the developing agent is consumed, and a proportional amount of byproducts are released into the developer. These amounts are gonna be the same regardless of who made the developer.

What this means is that all high-quality C-41 developers are gonna be affected to the same extent as you develop film. So this thing they call "capacity" of the developer almost certainly depends on how much variation one is willing to accept. In other words, a tolerance for how much the activity of the developer falls off.

Historically Kodak has been fairly conservative with their instructions - they didn't want customers to run into quality problems. So, as I recall, they spec a C-41 developer capacity of something like 4 "rolls" per liter of developer. You can probably count on this to stay well within "spec" tolerances (per use of process control strips), meaning a professional level of processing. I would guess that one could probably do about double the film (provided it is not heavily exposed) and still stay mostly within process specs. Beyond that... ? Fwiw if the film is only lightly exposed it only slightly affects the developer, so this is another factor.

If the Rollei developer "allows" 16 rolls per 500 ml (equivalent to 32 rolls per liter) this is something like 8 times more than Kodak recommends. I would guess that Rollei probably cautions the customer that it is up to them to decide if the quality is good enough. (If you're gonna scan everything you might not be that concerned about processing specs.)

mshchem · Mar 14, 2023

I am interested in seeing the Filmomat in action! Being able to sit and watch. Set it up on a kitchen counter and have your friends over for drinks.
Sounds like the OP has a plan, good luck with your outfit, report back please when operational!
Best Regards Mike

Xylo · Mar 14, 2023

ymc226 said:
used the accordion type bottles that minimized extra volume

So far, I've never had great success with those bottles. They always leak air and I end-up with oxidized chems. That's why I switched to glass.

Tel · Mar 14, 2023

ymc226 said:
I've never done color before. Why don't you think stabilizer is needed? If not, it would simplify things more. The only color films I am using (120 and 135) are Kodak Portra 160 and 400.

There are some earlier threads on Photrio that spell out the chemical reasons for this, but the takeaway is that the film manufacturers changed their formulations sometime in the early days of this century (IIRC) to eliminate the need for stabilizer. But the manufacturers of the C-41 kits keep including it, perhaps to accommodate users who are developing old stock. (VERY old stock!)

ymc226 · Mar 14, 2023

mshchem said:
I am interested in seeing the Filmomat in action! Being able to sit and watch. Set it up on a kitchen counter and have your friends over for drinks.
Sounds like the OP has a plan, good luck with your outfit, report back please when operational!
Best Regards Mike

Will do Mike. I plan on developing both B&W as well as color. The negatives from the one convenient lab close to me have tiny white spots on the color negative, especially on 120 film so will not go there and just wait for the Filmomat to arrive.

ymc226 · Mar 14, 2023

Tel said:
There are some earlier threads on Photrio that spell out the chemical reasons for this, but the takeaway is that the film manufacturers changed their formulations sometime in the early days of this century (IIRC) to eliminate the need for stabilizer. But the manufacturers of the C-41 kits keep including it, perhaps to accommodate users who are developing old stock. (VERY old stock!)

Thanks Tel, I did read the pertinent postings regarding not needing stabilizer. I will just do a few rinsing with distilled water manually at the end in addition to the rinses the Filmomat performs as part of its cycle to minimize spotting.

MattKing · Mar 14, 2023

Tel said:
There are some earlier threads on Photrio that spell out the chemical reasons for this, but the takeaway is that the film manufacturers changed their formulations sometime in the early days of this century (IIRC) to eliminate the need for stabilizer. But the manufacturers of the C-41 kits keep including it, perhaps to accommodate users who are developing old stock. (VERY old stock!)

In addition to the other role that stabilizers played with the older films, they also include components that help your C-41 negatives resist bacteria induced deterioration over time.
That role is still performed by the old stabilizers, but is also performed by the current Final Rinse.
And both also supply a surfactant to aid in drying.
If you want your negatives to last, you do not want to have the last bath be water or water plus just a surfactant. You want there to be a bactericide as well.

mshchem · Mar 14, 2023

https://www.uniquephoto.com/kodakflexifinalrinseandreplenisher10l

THIS IS YOUR F8NAL RINSE. CHEAP.
Everything Matt says!

mshchem · Mar 14, 2023

https://www.uniquephoto.com/kodakflexiclrrableachreplennrtomake5l6600274

And this is the Bleach C-41 RA , like what is used in minilabs, bleach time cut to 1 minute. You will need a starter, also at Unique. This bleach will keep for years, this loves oxygen, needs oxygen to work.

https://www.uniquephoto.com/kodakc41rflexicolorfixerandreplenishertomake10l

Fixer C41-RA....

Here's the developer REPLENISHER. 5 Or 20L size You will need a bottle of starter for this too.

https://www.uniquephoto.com/c41devrepllorrtm5lekkodakxhazhazsp183206088231672

https://www.uniquephoto.com/kodakc41entwicklerflxclrdevrrplr3667805

KODAK SINOPROMISE MUST BE BACK AS THIS IS IN STOCK A5 UNIQUE PHOTO.

Duceman · Mar 14, 2023

Tel said:
My experience may not relate directly to your plans, but might help you with your calculations anyway. I've only used a liquid kit once; I prefer the dry powder kits because of their long shelf life. I use the Unicolor 1L kits, typically buying them in lots of four or five and storing unopened ones for up to a couple of years. I have four 500mL brown glass bottles with screw-caps that I use exclusively for C-41. I mix up a liter of working solution and divide that in half, filling two 500mL bottles with dev and two with blix. I store them on a shelf in a cabinet in my kitchen (no refrigeration). Each half-liter typically gives me 8-10 rolls. The unopened bottles keep for a long time: I just hit roll 16 for a liter that I mixed on October 6. It was looking quite clear and probably was good for more, but I have a rule that I arbitrarily follow, to dump each pair of bottles after 8 rolls even if it looks good to go for more. I found in the past that C-41 tends to fall off a cliff when it does fail and I don't like to risk that.

Excellent idea. Wish I would have thought of it. But this does limit to essentially developing one roll at a time, regardless if 135mm or 120. At least in my tanks where I'd need ~600mL to do two rolls of 135mm at once.

Duceman · Mar 14, 2023

MattKing said:
If you want your negatives to last, you do not want to have the last bath be water or water plus just a surfactant. You want there to be a bactericide as well.

I have heard of some who use PhotoFlo as the final rinse to reduce streaks. I take it that doing so would be a no-no?

MattKing · Mar 14, 2023

Duceman said:
I have heard of some who use PhotoFlo as the final rinse to reduce streaks. I take it that doing so would be a no-no?

There seem to be a number of people out there who don't think it is necessary to keep negatives once they have been scanned. For those people, this would be fine.
Final Rinse contains the same or similar surfactants as PhotoFlo does, so it fulfils that part of PhotoFlo's role.
For clarity, the bactericide is only necessary in colour and black and white C-41 processed negatives, because the C-41 process removes the silver from film.
Processed "normal" black and white film still has silver in it, and silver itself is an excellent bactericide.

Xylo · Mar 15, 2023

I never thought about bacteria. I always thought that the stabilizer was just sodium sulfite to help reduce the amount of fixer left in the emulsion (a bit like a hypo clearing bath).

koraks · Mar 16, 2023

Xylo said:
I always thought that the stabilizer was just sodium sulfite to help reduce the amount of fixer left in the emulsion

No, and it's easy to see why this isn't the case, since the stabilizer or final rinse is the last bath the film goes through. Had it been a hypo-clear type of bath, subsequent washes would be required.
Film does not really need a hypo clear step.

Please refer to this thread for more info about stabilizers and/or final rinses: https://www.photrio.com/forum/threads/the-definitive-word-i-hope-on-color-stabilzers.89149/unread
It'll also make clear what the different functions are and which ones are required in which use cases.

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