Kodak Color Negative C41 Kit

Fatih Ayoglu · Jun 7, 2025

Hi all,

So this kit, albeit only 2.5l available in UK, is cheaper per liter than my go to Fuji Hunt XPress kit so I am planning to switch it. However the instruction manual does not specify how to extend time or how many films can be developed per liter solution.

Should I assume the kit is based on one time use, so discarding after each session?

(Because I'll use it with Jobo 2500 series tanks, so 150ml per roll will make about 16x 35mm film I suppose)

Cheers,
Fatih

blee1996 · Jun 7, 2025

If you are doing one-shot developer, then it does not really matter right?

I use the 5L kit, and divide into 5x 1L bottles because my Paterson tank is 1 liter. For each 1L set, I reuse for 16 rolls of 120/135 film with decent results. I adjust color dev time after each 4 rolls.

Fatih Ayoglu · Jun 7, 2025

I am asking if the developer is to be used as one-shot or can be reused with extending time.

Because Kodak has not published any time correction past 4 films, unlike other manufacturers.

MattKing · Jun 7, 2025

Fatih Ayoglu said:
I am asking if the developer is to be used as one-shot or can be reused with extending time.

Because Kodak has not published any time correction past 4 films, unlike other manufacturers.

Ask CineStill and Photo Systems, who are the distributors and the manufacturer. Neither of the Kodaks have any direct connection to this, other than Eastman Kodak's licensing of the "Kodak" brand name.
By the way, if you ask the manufacturer, the response will come from the distributor

mshchem · Jun 8, 2025

I looked at the old (2005) Kodak cis 211, indicating for a small 1 US pint tank (ca.500mL) develop (2) 36 exposure 35mm use developer once and toss. The bleach and fixer can be reused.

If I was going for maximum use out of 2.5 liters I would make up the 2.5 liters with pure water, then store in full 500ml and 1L bottles.

You can reuse the developer. It's not a great practice, especially if you are storing the partially used developer.

I would be shocked if the Bellini developer had any real capacity differences from the current Kodak branded C-41 kit.

Mr Bill · Jun 8, 2025

Fatih Ayoglu said:
I am asking if the developer is to be used as one-shot or can be reused with extending time.

Because Kodak has not published any time correction past 4 films, unlike other manufacturers.

Kodak is basically being conservative with respect to "quality" standards. More specifically with respect to the "process control charts." This is where someone periodically processes a pre-exposed "control strip," measures the resulting test patches (using a status M densitometer), and compares them against the manufacturer-supplied "reference strip." There are also standard spec limits (tolerances) for the differences. (See Kodak's Z-131 (I think) for more information than you probably want.)

If you stay with the Kodak guidelines, and you have more or less average exposures on your film, you will most likely stay comfortably within the process spec limits. If you go beyond Kodak's guidelines, say double, you will most likely get some of the color plots dancing outside of the spec limits. Is this a problem? Well, it depends. It certainly would NOT be professional-level processing. But if one always (only) scans film...?

FWIW "time corrections" are not a normal thing within the official C-41 process.

Regarding different brands of C-41 developer, these are all fundamentally the same. (If they were not they wouldn't be able to match the process "activity" specs.) So when you see claims for extended roll counts being processed per unit of developer, most likely the chem maker is simply working with more, uhh, relaxed tolerances.

FWIW this is one of the things I worked with for years and years, in an outfit where we ran something like 40 to 50 control strips EVERY DAY. (I probably taught a couple dozen techs, over the years, how to troubleshoot process problems, etc.) We had done hundreds and hundreds of chemical analyses, mostly partial, on color developer solutions when studying effects on control charts, etc. There really is not a lot of mystery to it once you see some analytical data vs control chart plots.

Mr Bill · Jun 8, 2025

mshchem said:
I would be shocked if the Bellini developer had any real capacity differences from the current Kodak branded C-41 kit.

I would pretty much agree with you, except... if I were gonna try to sell a product where I wanted to claim "more developing capacity" I might be inclined to start out with an overly active mix. Instead of starting out with an "on-spec" control chart, roughly centered on the plots, I could design the mix so as to give control plots near the high end of spec. This gives more leeway before falling out of spec on the bottom end. So... more rolls per developer volume before falling out of spec.

I note that the OP is using a Jobo processor with a limited quantity of developer to begin with. So I'm a bit skeptical this could reliably give centered on-spec processing.

Tom Kershaw · Jun 8, 2025

Mr Bill said:
I note that the OP is using a Jobo processor with a limited quantity of developer to begin with. So I'm a bit skeptical this could reliably give centered on-spec processing.

I've posted on this subject elsewhere on the forum, but in my experience of processing C-41 in a Jobo, I would stick to 4 rolls of 120 or equivalent per litre, with no re-use. My experiments with re-using / replenishing developer showed a mark reduction in colour quality, even when negative density still appeared acceptable.

For the original poster, depending on the quantity of film to be processed, using individual solutions rather than a kit may prove to be more economical.

mshchem · Jun 8, 2025

When you consider the big picture, chemistry is dirt cheap.

It's almost always cheaper to have a good lab process your color film.

I love my darkroom and developing film, I like the convenience and the experience.

I don't buy kits.

Developer replenisher is cheap. If I throw away some of it fine.

Flexicolor Bleach is eternal .

Fixer is Fixer, I buy a Fuji universal fixer works for all color film, dilution is different.

Starter is a problem as Kodak-Cinestill is only selling it in a case of 6 bottles. That's 10 lifetimes supply.

brian steinberger · Jun 8, 2025

I’ve just gotten started with the Bellini kit. And the instructions clearly state the increased time after each 4 rolls of film developed. However, I keep reading about how developer should not be reused. I would prefer to have the highest quality possible. I’m developing in a standard SS tank with SS reels. Would it be silly for me to use a developer one shot? I know Jobos use much less solution per film

koraks · Jun 8, 2025

brian steinberger said:
I would prefer to have the highest quality possible.

Then one shot is the way to go, or a high-volume, closely monitored replenished system. The latter is usually impractical for home users.

pentaxuser · Jun 8, 2025

"I use the 5L kit, and divide into 5x 1L bottles because my Paterson tank is 1 liter. For each 1L set, I reuse for 16 rolls of 120/135 film with decent results. I adjust color dev time after each 4 rolls"

I am unsure who makes this 5L kit but blee's post above suggests that with his 5L kit with re-use he gets considerably more films developer than Fatih will get with discarding the dev after each film

If what I have said is obvious to all then I need not have said it but you'd imagine that if blee had seen any problems with his level of re-use he'd have said. So assuming he has not had any issues then the only question remains" Has he been just been lucky?

Yes it seems that he may not be using the smaller Jobo amounts of 150ml but isn't it reasonable to assume that the Jobo system produces the same results with rotary as does inversion with more developer?

pentaxuser
--

mshchem · Jun 8, 2025

I have a 1996 Kodak Color Darkroom Dataguide, shows developing amateur color negative films (Kodak Gold) using extended times processing in a 1 pint SS tank. 1st 2rolls 35mm 36exp 3:15, 2nd 2 rolls 3:22, 3rd 2 rolls 3:27, 4th 2 rolls 3:31 for a capacity of 8 rolls per pint. The guide warns DO NOT use time extension with Ektar and other professional films.

This is not how I would proceed, but this is how these procedures creep into practice.

Fatih Ayoglu · Jun 8, 2025

koraks said:
Then one shot is the way to go, or a high-volume, closely monitored replenished system. The latter is usually impractical for home users.

I’m trying to follow up your recommendation to use Minilab chemistry from Fuji, but 2x10 litre dev is £160 in here. You do it for €0.50 per roll mine comes as £1.20

blee1996 · Jun 8, 2025

There are many levels of quality expectation from different people: on the high end of spectrum people need professional quality so they can sell fine art prints to museums, on the low end of spectrum people wants the convenience plus good enough quality for scans and social media share. I'm more towards the right end of spectrum, thus re-use C41/E6/ECN-2 chemistry for my 1L Paterson tank.

Therefore we all pick what is good enough for ourselves.

brian steinberger · Jun 8, 2025

What kind of issues will show up with reuse of developer within the manufacturers recommendations? Are we talking density issues? Color balance issues?

Fatih Ayoglu · Jun 8, 2025

I think a bit of both. On the new Kodak Cokor chemistry manual, it says if your negatives are thin, increase dev time

koraks · Jun 9, 2025

blee1996 said:
on the high end of spectrum people need professional quality so they can sell fine art prints to museums, on the low end of spectrum people wants the convenience plus good enough quality for scans and social media share.

It's more about mentality than about final output, I think. Most photographers I've interacted with who produce work that occasionally ends up in museums aren't all that interested in chemistry etc. They want good negatives and most of the time they don't give a hoot how they materialize. It's the amateur photographers who are the fussy lot, by and large.

brian steinberger · Jun 9, 2025

Would it be safe to assume we would get good to excellent results with these kits (I’m using Bellini) if we used them within a week and developed half the recommended amount of film with them?

If so, for me that would work out to the same price as sending to my lab, and I get cleaner negatives.

koraks · Jun 9, 2025

Focusing on the color developer for a C41 or ECN2 system, as this is the color-critical aspect: there are generally speaking two mechanisms that affect variance in the output. Firstly it's degradation of the chemistry due to use and static storage. The other is leaching of byproducts into the developer due to use (think of halides). The former has implications for how the chemistry is best stored, which will affect its shelf life. The latter implies that reuse without replenishment will always induce process shifts, regardless of chemistry age or storage conditions.

The takeaway of this is that provided favorable storage conditions, either a one-shot use system or a replenished system should be perfectly stable. All other configurations will exhibit process variations, which may or may not be acceptable. To the best of my knowledge the only real way to track that is to process test strips along with the 'production' film and perform densitometry on these strips.

Not a straight answer to your question, I know, but I think you can work out the answer based on the usage scenario you have in mind. Note that in the scenario as you wrote it down the film batch size and developer volume are missing - hence the 'no straight answer'!

brian steinberger · Jun 9, 2025

Could the Bellini developer be replenished with more Bellini developer? Or is C41 developer replenisher something different?

mshchem · Jun 9, 2025

I would like to see Cinestill offer single 1 L bottles of Flexicolor developer starter and 1L bottles of Flexicolor bleach starter.
Fuji is no better in the US the starters are sold I 1 gallon bottles.
Unique Photo used to sell the 1.2L bottles of Alaris Flexicolor starters for a reasonable price.

mshchem · Jun 9, 2025

brian steinberger said:
Could the Bellini developer be replenished with more Bellini developer? Or is C41 developer replenisher something different?

The replenisher doesn't contain bromide and is more concentrated. I would be more comfortable using replenisher (pretty much any brand) to replenish (pretty much any brand) of developer.

Problem lies in not using control strips when replenishing. Things can get screwy.

koraks · Jun 9, 2025

brian steinberger said:
Could the Bellini developer be replenished with more Bellini developer? Or is C41 developer replenisher something different?

See @mshchem's remark above; it's spot on. Developer is not replenisher. AFAIK Bellini does not market a replenisher for the home/amateur market. They may be manufacturing it for larger-scale users; I'm not sure.

MattKing · Jun 9, 2025

blee1996 said:
There are many levels of quality expectation from different people: on the high end of spectrum people need professional quality so they can sell fine art prints to museums, on the low end of spectrum people wants the convenience plus good enough quality for scans and social media share. I'm more towards the right end of spectrum, thus re-use C41/E6/ECN-2 chemistry for my 1L Paterson tank.

Therefore we all pick what is good enough for ourselves.

I spent a fair amount of time in my younger years both selling photography and doing colour printing for others who sold their photography.
As a result, I tend to be really bothered by the sort of colour problems that many others barely notice. A small amount of colour crossover is enough to distract me from the content of a print. And a 10CC colour cast is enough to make me shiver -
So yes, quality expectation varies - and not just because of the intended use.

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