500 rolls from 10L of developer (C41)?

athbr · Jun 20, 2019

Just found decently priced minilab bulk chemicals for C41.

The supplier (local company not fuji or kodak) is selling a kit that claims 500 35mm 24 exp rolls capacity. The developer stock makes 10L working solution with 20ml replenishment rate (which works out to 500).

Is this right? This would mean 50 rolls per litre compared to the 8-10 rolls of the unicolor and cinestill kits (those are for 36exp rolls but even so its a huge difference).

Only explanation I can imagine is that non-replenished solutions might have lower capacity because there needs to be a minimum of fresh CD4 before the developer dies off. Maybe?

Mr Bill · Jun 21, 2019

athbr said:
Is this right? This would mean 50 rolls per litre compared to the 8-10 rolls of the unicolor and cinestill kits (those are for 36exp rolls but even so its a huge difference).

Yep, sounds about right for Kodak LORR style replenishers. It's well known to people who have worked in the trade that replenished systems give the lowest chemical costs per roll.

You might wonder, why doesn't everyone use a replenished system? Well, there are several reasons. One is that it only works well if you have enough processing volume, otherwise the developer can go bad from "age" before you can thoroughly use it. A second reason is that the replenished system must be "monitored" by people who know what they're doing, and preferably have some specialized equipment (color densitometer, etc.) to help with this. If you don't "monitor" the results and make the appropriate adjustments (mainly to replenishment rates) your system can drift "out of spec." You can be in the position where you don't know if the results will be good or not. Whereas the method of mix fresh and develop only a small number of rolls is mostly fairly reliable without the hassles. Ultimately it's a case of the best balance between chemical costs and what your time is worth - you don't want to spend a dollar's worth of your time to save a half-dollar of chemical costs.

athbr said:
Only explanation I can imagine is that non-replenished solutions might have lower capacity because there needs to be a minimum of fresh CD4 before the developer dies off. Maybe?

Well, it's a little more complicated than that. One thing to consider is that an LORR replenisher is more concentrated than what is known in the trade as "tank solution," the mix actually used to develop film. So it's sort of an apples to oranges comparison.

I sort of discussed some of these issues in the link below. I was mainly talking about the Jobo-style processing machines, but there are some references to the Kodak Z manual for the process, which is probably your best source of info:

https://www.photrio.com/forum/threads/best-c41-chemical-kits.166974/#post-2172993

foc · Jun 21, 2019

Is that a cartridge type chemical or bottles?

Remember that minilab chemicals are designed for a replenished system where the dev tank solution is basically season chemistry ( When first mixing a dev tank solution of rep chemical you have to add a starter ). The rep rate of 20ml per 35 exp 35mm film would be correct.
Unless you have a machine processor or a large hand line then I can't see any advantage, (in fact I can see big trouble).

As Mr Bill said above there is a lot involved in a rep system , even an automated system.

MattKing · Jun 21, 2019

It is always important to realize that every replenishment system relies on both regular addition of fresh chemicals and regular removal of process byproducts.
In some cases, it is the byproducts that have the biggest affect on capacity.

cmacd123 · Jun 21, 2019

MattKing said:
regular removal of process byproducts.
In some cases, it is the byproducts that have the biggest affect on capacity.

If the process is running on a big machine that is doing many rols a day, the "carry out" (chemical that stays on the film as it leaves the tank) will almost perfectly match the replenishment rate. the modern low volume chemicals allow for lower numbers of films while still keeping a stable process. the makers also recoment that the tanks be toped up with distilled water to make up for the amount of solution that evaporates. I had a batch of film ruined by a local minilab who did not have the volume needed and gave me back film that was by my estamate 50% overdeveloped.

athbr · Jun 21, 2019

The kit does come with a starter. It is bottled.

I am a low volume amateur photographer developing manually in paterson tanks. That said,
If I could even get a 10th of this capacity I’d be already saving money compared to labs and imported unicolor kits. These are unfortunately just facts of life in the developing world.

I have seen others here coming to similar conclusions about process economy.

Any advice on how to use a kit like this reliably for low volume?

Can i try and run it unreplenished. Should I try and get the 50 rolls out of the litre (adding 10% every 5 rolls)? Perhaps I should aim for 25 just to be on the safe side?

Any and all advice welcome.

cmacd123 · Jun 21, 2019

unreplenished, You probably will get the same extended use results as with the "home Kits" 5 or 10 rolls depending on how critical your taste is. Their is nothing magic with the Photofinisher package, other than the photofinishers being able to run daily test strips and adjusting the replenishment rate, and posibly the Ph of the solutions to try and keep the process under control.

You may want to read the Kodak Alaris manual : https://imaging.kodakalaris.com/sites/uat/files/wysiwyg/pro/chemistry/z131.pdf

Actually reading in that manual, it does say you can get 4 rolls of 135-36 per liter of the chemicals in using it UNreplenished (edit, I did mean to say UNreplenished)

The section on process monitoring and plotting readings from Control strips is in section 5 of the Z131 manual.. I see that adorama lists the control strips online.

foc · Jun 21, 2019

Do you have a brand name and pack size for the kit?
Did you search online for info about it? Most manufacturers have data sheets that you can download like the Kodak z131 pdf.

athbr · Jun 21, 2019

Its a Brazilian manufacturer called HR Color. So nothing anyone here would know much about I’d imagine

I’ll call up the sales agent to get this documentation.

foc · Jun 22, 2019

There are not too many manufacturers of C41 chemistry in the world. Could it be a rebadged pack?
If you could see the box, it would say where it is manufactured.
I am interested to see how it will work out.
Best of luck with it.

Murray Kelly · Jun 25, 2019

If your question is about capacity there is a thread here by David Lyga that espouses one-shot, high dilution, and temperature variation from normal. 40 films or more per litre. With your supply problem it may help you. Locally, there is now one (AFAIK) lab in this city of 2 million. We have to get adaptable to survive.

athbr · Jun 26, 2019

Thanks Murray. I'll check David's material. Sounds promising.

mshchem · Jun 26, 2019

athbr said:
Thanks Murray. I'll check David's material. Sounds promising.

As long as you make replenisher first, then add starter and dilute to the "working tank" solution it will work fine. The 10 liters is probably for replenisher, it may make more "working tank" normal developer. Even if you are very conservative and make 1 liter of working developer, and use it for 10 rolls of film you will get over 100 rolls. Jobo machines use 140 mL per roll of 35mm film, one shot. That's 7 rolls per liter working solution.
This should be a RA type of C41, has separate bleach and fixer with shorter times.
I'm just looking at my Kodak Flexicolor. The developer replenisher makes 10L of replenisher. To make the developer, 763ml of replenisher, 30ml of starter and 207 ml of water.
Download the Z-131 Flexicolor manual, it can be confusing as anything. But it makes good reading.
The bleach will last for a long time. If your vendor sells developer replenisher separately you can use the developer and toss, replenish the bleach and fixer.
I've developed a lot of color film in Paterson tanks, works great.

athbr · Jun 26, 2019

mshchem said:
As long as you make replenisher first, then add starter and dilute to the "working tank" solution it will work fine. The 10 liters is probably for replenisher, it may make more "working tank" normal developer. Even if you are very conservative and make 1 liter of working developer, and use it for 10 rolls of film you will get over 100 rolls. Jobo machines use 140 mL per roll of 35mm film, one shot. That's 7 rolls per liter working solution.
This should be a RA type of C41, has separate bleach and fixer with shorter times.
I'm just looking at my Kodak Flexicolor. The developer replenisher makes 10L of replenisher. To make the developer, 763ml of replenisher, 30ml of starter and 207 ml of water.
Download the Z-131 Flexicolor manual, it can be confusing as anything. But it makes good reading.
The bleach will last for a long time. If your vendor sells developer replenisher separately you can use the developer and toss, replenish the bleach and fixer.
I've developed a lot of color film in Paterson tanks, works great.

FYI the math works out pretty cheap for 100 rolls so I'm definitely not sweating it if that's all I get.

The only thing I'd like to stretch a bit longer is the bleach (it accounts for about half the cost of the kit). Everything everyone has mentioned so far has indicated that bleach is pretty muscular.

I was hoping to get 40 rolls per litre with frequent regeneration. I could live with 20.

mshchem · Jun 26, 2019

athbr said:
FYI the math works out pretty cheap for 100 rolls so I'm definitely not sweating it if that's all I get.

The only thing I'd like to stretch a bit longer is the bleach (it accounts for about half the cost of the kit). Everything everyone has mentioned so far has indicated that bleach is pretty muscular.

I was hoping to get 40 rolls per litre with frequent regeneration. I could live with 20.

If you follow the replenishment scheme of the supplier the bleach will probably last for the rest of your life . C-41 minilab bleach is eternal, it loves oxygen so shake it well now and then. The bleach probably has capacity to equal to 2 times the developer. The fixer is just fixer so it should be cheap.
I'm sure Brazil has good C-41 chemistry. All the Kodak Alaris stuff is made in China, that's what we get. I suspect that these are commodity chemicals shipped in bulk totes from various manufacturers. Could be the exact same material. C41-RA is designed to run in most existing minilabs, should work fine.

athbr · Jun 26, 2019

mshchem said:
If you follow the replenishment scheme of the supplier the bleach will probably last for the rest of your life . C-41 minilab bleach is eternal, it loves oxygen so shake it well now and then.

Could be wrong but PE mentioned before that one can regenerate the bleach using KBr plus a good shake. That way one doesn't have to keep topping up with the stock replenisher and use up all that expensive EDTA.

Not sure how much KBr to add though.

athbr · Jun 26, 2019

https://www.photrio.com/forum/threads/c-41-bleach-replenisher-vs-regenerator.21146/

This thread right here. Was actually NaBr instead.

RPC · Jun 26, 2019

athbr said:
Thanks Murray. I'll check David's material. Sounds promising.

If you use David Lyga's C-41 diluted developer method, you should test it compared to proper C-41 developer and see if it is acceptable to you. C-41 development is a fairly critical process and his method has been reported by some who have tested it to give out-of-spec results, as theory dictates such a process should.

mshchem · Jun 26, 2019

athbr said:
https://www.photrio.com/forum/threads/c-41-bleach-replenisher-vs-regenerator.21146/

This thread right here. Was actually NaBr instead.

There's no greater authority on Bleach and Fixer. I'm pretty sure PE invented Blix for paper.

All I know is I bought one 5 L bottle of Flexicolor RA Bleach. I have been using it for 4 or 5 years and it's still 85% full. (There's a Bleach Starter too.)

RPC · Jun 26, 2019

athbr said:
https://www.photrio.com/forum/threads/c-41-bleach-replenisher-vs-regenerator.21146/

This thread right here. Was actually NaBr instead.

That's interesting because I was sure that in other threads he said you should regenerate with ammonium bromide instead of sodium bromide. IIRC it had something to do with sodium bromide slowing down the bleaching, so if he doesn't chime in here you may want to research a little more.

foc · Jun 28, 2019

I can remember years ago, regenerating EP2 bleach overflow with glacial acetic acid.

500 rolls from 10L of developer (C41)?

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