Getting more rolls out of C-41 chemistry / aka. Have you tried the Adox/Tetenal/Rollei/Bellini C-41 kit?

dcy · Aug 24, 2025

There are many C-41 development kits, but their capacity claims follow a consistent pattern:

Kodak: 8 rolls of 135 / Liter.
Arista: 8 rolls of 135 / Liter + a note that you might get more but YMMV.
Unicolor: 8 rolls of 135 / Liter + a note that you might get more but YMMV.
Bellini: 12 Rolls of 135 / Liter + progressively longer dev times after the 3rd roll.
Adox: 16 Rolls of 135 / Liter + progressively longer dev times after the 4th roll.
Rollei: 16 Rolls of 135 / Liter + progressively longer dev times after the 4th roll.
Tenetal: Defunct, but reborn as Adox.

C-41 his highly standardized, and a look at the MSDS of these kits shows how similar they are. Of course they all use CD4, and other ingredients vary in ways that look entirely equivalent (as you'd expect).

Clearly, there is nothing special about Bellini/Adox/Rollei/Tenetal chemistry. They just made a different guess than PSI (who makes Kodak/Arista/Unicolor) about how people will use the kits and/or how much color shift users will tolerate. For reference, here are the times for 1 L of developer:

(Edit: Fixed the table formatting)

.	3 min 15 s	3 min 30 s	3 min 45 s	4 min
Kodak	Rolls 1-8	.	.	.
Arista/Unicolor	.	Rolls 1-8	.	.
Bellini	Rolls 1-3	Rolls 4-6	Rolls 7-9	Rolls 10-12
Adox/Tenetal/Rollei	Rolls 1-4	Rolls 5-8	Rolls 9-12	Rolls 13-16

Note: This is for rolls of 36 exp 135 film, or 120 film. All developed at 38°C.

My Question: Have you tried any of the kits that say to process more rolls by extending the dev time? How did it go? How do you feel about the color shift?

mshchem · Aug 24, 2025

All C-41 developer has same capacity, some companies state that you can increase the number of rolls per unit if you are willing to accept degradation in quality.

One other thing you're going to really need to extend Blix times as the fixer portion is really going to be exhausted.

koraks · Aug 25, 2025

The first rolls & sheets of C41 film I processed myself, I ran through a liter of Rollei chemistry. I stretched that liter until things started to look really iffy even to my untrained eye. In hindsight, I had blown over half the film I had processed to smithereens by doing so. Some of those negatives were in principle exposed just fine, but cannot be printed. At the time, I felt they scanned just fine (I now disagree with myself on that, too), so I thought everything was going great and capacity numbers were grossly understated.

The gist of the story is that the failure is a creeping one. You'll only realize it when it's far too late.

gbroadbridge · Aug 25, 2025

dcy said:
My Question: Have you tried any of the kits that say to process more rolls by extending the dev time? How did it go? How do you feel about the color shift?

I'm pretty sure I've always used kits that stated to extend the dev time and blix time.

Most recently (last couple of years) Tetenal and Ilford - before that was Agfa.

I haven't noticed any colour shifts that can't be attributed simply to shooting fixed colour balance film in varying light conditions without CC filters in front of the lens when required.
I always stick to the box instructions and toss after 16 rolls per litre and always at C41 process temperature.

Spektrum · Aug 25, 2025

dcy said:
My Question: Have you tried any of the kits that say to process more rolls by extending the dev time? How did it go? How do you feel about the color shift?

There was already a similar topic here on the forum and you even participated in it.

Kodak Gold 200 & Adox C41 kit - help with troubleshooting heavy colour casts

Just another note to add that I've further refined my development workflow with the ADOX C41 kit by controlling temperature even earlier, at the pre-soak stage. I'm now doing a longer pre-soak, using 1L of water kept in the sous vide bath running at 39 Celsius. Sampling the temperature of the...

www.photrio.com

Two months ago, I argued that, regardless of the kit manufacturer's claims, you shouldn't exceed 8-10 rolls of film per liter of developer and use the developer within 7-10 days.
Now, after two months, I believe the maximum number of rolls shouldn't exceed 8 (really, not a single roll more!).
There's no point in skimping on chemicals if you want consistent results. Of course, many of us scan film and process it digitally. Also, many of us like different kinds of color shifts because they feel the artistic spirit.

Exactly as @koraks wrote, excessively extending the amount of developed film per liter, even with the development time correction, will have consequences not only in the form of color shifts but also underdevelopment in shadows, sometimes increased grain, etc.
Even if you scan your film, do not skimp on chemicals.
You'll realize this when it's too late.

dcy · Aug 25, 2025

Spektrum said:
There was already a similar topic here on the forum and you even participated in it.

Kodak Gold 200 & Adox C41 kit - help with troubleshooting heavy colour casts

Just another note to add that I've further refined my development workflow with the ADOX C41 kit by controlling temperature even earlier, at the pre-soak stage. I'm now doing a longer pre-soak, using 1L of water kept in the sous vide bath running at 39 Celsius. Sampling the temperature of the...

www.photrio.com

Depends on what one means by "similar". Looking back at that thread:

(1) The discussion I that thread was not about whether increasing the dev time is a good way to get more rolls out of a kit.

(2) My entry into the conversation was to about blix.

I do not remember whether I read your comment about how many rolls you can get out of a kit. But if I did read it, I do not think I would have necessarily made the connection to my question here about increasing the development time.

Spektrum said:
Exactly as @koraks wrote, excessively extending the amount of developed film per liter, even with the development time correction, will have consequences not only in the form of color shifts but also underdevelopment in shadows, sometimes increased grain, etc.
Even if you scan your film, do not skimp on chemicals.
You'll realize this when it's too late.

My take-away from @koraks ' comment and the one from @gbroadbridge was that trying to eye-ball the color is a recipe for failure, and I should instead pick a number of rolls I will process with each liter and stick to it, even if a color shift is not apparent.

loccdor · Aug 25, 2025

Agreed with Koraks. I used to do 30 films in a 1 liter C-41 kit. Then I realized I was pushing it and did 20. Now, I'd probably do about 15 or 16 at the max.

When you calculate the cost of chemicals per roll of film and make that into a percentage of your total photography cost, it's small and doesn't make sense to skimp. Years ago when it was easy to find film for $1 or $2 a roll, it might have been okay for someone learning and taking their "worst first 10,000" pictures.

halfaman · Aug 25, 2025

The biggest chalenge is that it is very difficult to judge a color negative film. C-41 chemistry is always going to deliver something, even when you pass the acceptable thereshold, but most probably you are not going to notice it on the film.

The instructions for reuse only makes some sense if you are doing manual inversions, for rotary processing things are not so clear. With 1 liter I can process in my Jobo up to eigth 35 mm or ten 120 rolls, way above the limit of 3-4 rolls per batch described. In the case of 120 format (my usual case), the advantage of reusing Bellini chemistry is very little (12 Vs 10 rolls). With Adox/Tetenal I can process substancially more rolls (16 Vs 10) but demanding much more time to develop (four batches instead of one). Same thing happens with 600 ml (six 120 rolls) or 250 ml (two 120 rolls). End of the story: I don't reuse with rotary processing. I buy minilab chemistry instead, that can be much more cheaper than amateur kits, and my current development cost is around €1 per roll.

dcy · Aug 25, 2025

loccdor said:
Agreed with Koraks. I used to do 30 films in a 1 liter C-41 kit. Then I realized I was pushing it and did 20. Now, I'd probably do about 15 or 16 at the max.

Thanks! That 15-16 / L is still a lot more than the mere 8 recommended by Kodak, and closer to the Adox/Rollei recommendation.

loccdor said:
When you calculate the cost of chemicals per roll of film and make that into a percentage of your total photography cost, it's small and doesn't make sense to skimp...

So far I have been shipping my film to a lab, which costs as much as the film. I recently ordered the Kodak 2.5 L kit. If I process 8 rolls / L, that will cut my development cost my more than half, but it'll still be 42% of the price of Kodak Gold. If I can reach your 15-16 rolls / L max, or just 12 rolls / L but switch to Kodak's 5 L kit, my development cost would become 21% the cost of the film. I think that is a good target to aspire to.

Owlch · Nov 11, 2025

Hi. New member here just to share my experience regarding roll capacity. I came from a Google search and this post really says what I just noticed.

I’ve tried both Jobo and Ilford’s C-41 kits which are in fact both manufactured by Chugai in Japan. After having inconsistent results I noticed one potentially problematic design: their CD Part-C only features 25ml for 2.5L working solution, while Kodak’s has 94.6ml. This difference seems too much to me, so I dig a little deeper.

Upon checking the SDS of both Jobo/Ilford and Kodak (PSI) regarding CD Part C, their effective ingredient are both listed as 10-15%. I don’t know much about chemistry and its math, but together with their volume difference it then appears me that Jobo/Ilford’s kit cut corners significantly in its capacity. This is in line with their instruction manual which states for 1L working solution it needs extended dev time when processing 5 or more rolls of 135-36. Kodak’s states up to 20 and doesn’t need time compensation, which means 8/L.

Now correct me if I’m wrong: As I understand C-41 is a processing method designed to have a standardised CD dev time at 3:15 (unless some certain film stocks designed with “push” in mind), and no such thing as “if processing more just extend the time.” This really makes me think that not all C-41 kits are born equal when it comes to capacity.

I’ve also tried processing one roll with 500ml solution and it worked pretty well, both for C-41 and E-6, only not economical. This further supports my suspicion.

koraks · Nov 11, 2025

Welcome aboard @Owlch!

Could you perhaps link us to the SDS you found for the Jobo/Ilford chemistry? I'd like to verify what you relayed - not that I don't believe you, but to see if the contextual information gives some more insight and possibly an explanation.

From what you say, the possibility arises that the Jobo/Ilford product contains perhaps as little as 25% of the amount of developing agent as the Kodak/PSI chemistry. That would be odd, because I don't see any way (provided the pH is the same) to get the same degree of development with such a massive difference. In other words, if this is true, not just capacity would be affected - there would be more and more profound differences as well. I would expect the Chinese product to have a considerably higher pH, or the instructions to recommend a considerably longer development time and/or higher temperature.

Looking at the formulas and SDS for C41 developers, they turn out to pretty much all end up at around 4.5g of CD4 per liter of working strength developer. It would be really, really odd for a product to deviate from this by more than let's say 20% or so.

Owlch · Nov 11, 2025

koraks said:
Welcome aboard @Owlch!

Could you perhaps link us to the SDS you found for the Jobo/Ilford chemistry? I'd like to verify what you relayed - not that I don't believe you, but to see if the contextual information gives some more insight and possibly an explanation.

From what you say, the possibility arises that the Jobo/Ilford product contains perhaps as little as 25% of the amount of developing agent as the Kodak/PSI chemistry. That would be odd, because I don't see any way (provided the pH is the same) to get the same degree of development with such a massive difference. In other words, if this is true, not just capacity would be affected - there would be more and more profound differences as well. I would expect the Chinese product to have a considerably higher pH, or the instructions to recommend a considerably longer development time and/or higher temperature.

Looking at the formulas and SDS for C41 developers, they turn out to pretty much all end up at around 4.5g of CD4 per liter of working strength developer. It would be really, really odd for a product to deviate from this by more than let's say 20% or so.

Hi koraks,

I’ve only got the files and I just screenshotted them. I uploaded as attachments.

I could be wrong though and I honestly do hope they actually didn’t cut that much, given that Ilford’s kit is cheaper here.

koraks · Nov 11, 2025

Thanks for the quick follow-up! I had a quick peek and I do recognize what you also saw. The Jobo SDS for C41 developer part C lists 10-15% CD4 content in a 25ml bottle for 2.5l of working strength developer. This boils down to something like 1.5g CD4/liter of working strength developer. AFAIK the solubility limit of CD4 in water is quite high and I wonder if perhaps the SDS is simply incorrect and the actual CD4 content is higher than stated.

jl_nims · Nov 11, 2025

koraks said:
Welcome aboard @Owlch!

Could you perhaps link us to the SDS you found for the Jobo/Ilford chemistry? I'd like to verify what you relayed - not that I believe you, but to see if the contextual information gives some more insight and possibly an explanation.

From what you say, the possibility arises that the Jobo/Ilford product contains perhaps as little as 25% of the amount of developing agent as the Kodak/PSI chemistry. That would be odd, because I don't see any way (provided the pH is the same) to get the same degree of development with such a massive difference. In other words, if this is true, not just capacity would be affected - there would be more and more profound differences as well. I would expect the Chinese product to have a considerably higher pH, or the instructions to recommend a considerably longer development time and/or higher temperature.

Looking at the formulas and SDS for C41 developers, they turn out to pretty much all end up at around 4.5g of CD4 per liter of working strength developer. It would be really, really odd for a product to deviate from this by more than let's say 20% or so.

Koraks,

Here is what I found on the Jobo C41 sds active ingredients. Parts A and B attached.

Links are here and here. Oops, sorry, I was too late!

koraks · Nov 11, 2025

Thanks so much @jl_nims - it's very much appreciated! I found those, too; it's really puzzling. Very well spotted by @Owlch and it presents an interesting riddle.

Owlch · Nov 11, 2025

Thanks @jl_nims and @koraks ! Glad that I wasn’t entirely mistaken.

I do suspect the CD4 in Ilford/Jobo isn’t as extremely diluted as the SDS states, but given my inconsistent results I had to suspect it’s likely not enough to match their capacity claim without quality issues. I scan and grade them manually by sampling both unexposed and fully exposed film base to map the density range in Cineon Log space, so it is very picky about processing results.

The concerned negatives would come out a bit lighter to my naked eyes, and the scans look like underexposed with crushed shadows. A slight green colour shift observed on the Fujifilm 400 (USA), but not much on the 120 Gold 200. In fact the symptoms were more pronounced on the 400 roll.

These two rolls were processed with 500ml solution at 3:15 using Ilford’s.

MattKing · Nov 11, 2025

Oof - those both look really bad on my laptop. But of course there are too many variables too make any decisions based on that.

Cholentpot · Nov 11, 2025

Most I've ever done was 56+ through a standard Tenetal Blix kit.

This is 'round about roll 50 through the stuff. CVS 200 expired in 2006 and stored in iffy conditions. Shot at ISO 25-50 in a Rebel G. Yes, it needed a bit of help in post but I'm shooting expired film, I'm not looking for perfection. I don't think I can ask for more out of my kit, film and camera.

I switched over this year to FPP Bleach Fix kit. Got two 1 liters and combined so I can develop 5 rolls at once. Saved me loads of time and I think it looks better than the blix stuff.

gbroadbridge · Nov 11, 2025

Owlch said:
These two rolls were processed with 500ml solution at 3:15 using Ilford’s.

Need to see the negatives to make any assessment.

I've not seen any issues with Ilford C41 chems even after 13 rolls / 1.25l reused. Couple of shots here

Owlch · Nov 11, 2025

gbroadbridge said:
Need to see the negatives to make any assessment.

I've not seen any issues with Ilford C41 chems even after 13 rolls / 1.25l reused. Couple of shots here

Here are the negatives. The upper strip being lab processed, and the other was the Ilford batch. Slight inconsistent base colour on each strip could be the back light issue, not the films.

Any advice is appreciated

koraks · Nov 12, 2025

The main thing I see is that the bottom negatives are more blue; looking at the negatives there doesn't seem to be a lot of cyan or magenta dye being formed. In part this may be due to differences in lighting, but that's surely not the entire story.
Note that the density in the sky is roughly similar. If one developer would be starved in CD4 (with everything else being the same), I would expect a large density difference there. It doesn't appear to be the case. My first thought would be issues with pH (mixing error) and/or process temperature control - although both would logically also result in significant overall gamma differences.

Can you describe your process in detail, please?

PS: I can't make much of the comparison in post #16. The main thing that stands out is that the lighting was different (time of day). However, again, that's not the only/main factor in the color balance. Different types of film used can account for part of the difference. I suspect color grading after scanning plays a role here as well.

Owlch · Nov 12, 2025

koraks said:
View attachment 411089

The main thing I see is that the bottom negatives are more blue; looking at the negatives there doesn't seem to be a lot of cyan or magenta dye being formed. In part this may be due to differences in lighting, but that's surely not the entire story.
Note that the density in the sky is roughly similar. If one developer would be starved in CD4 (with everything else being the same), I would expect a large density difference there. It doesn't appear to be the case. My first thought would be issues with pH (mixing error) and/or process temperature control - although both would logically also result in significant overall gamma differences.

Can you describe your process in detail, please?

PS: I can't make much of the comparison in post #16. The main thing that stands out is that the lighting was different (time of day). However, again, that's not the only/main factor in the color balance. Different types of film used can account for part of the difference. I suspect color grading after scanning plays a role here as well.

koraks,

Most likely due to grading approach as you said. I've attahced my scan for the two frames. (Raw file -> linear tiff -> Resolve Cineon log invert -> RGB alignment in Dmin & Dmax -> matching film characterstic curve slopes -> output). Also, the negative strip image you worked on was taken on a wide spectrum (high CRI) white light panel, so dye crosstalk for CN was quite significant there.

I've attached a third sample, a roll of Superia Premium 400 processed with 500ml as well. No issue of crushed shadow or underexposed look to me.

koraks · Nov 12, 2025

Owlch said:
I've attahced my scan for the two frames.

I'm sorry, I can't make out anything from those images. They are inverted scans/photos, so what the negative might have looked like cannot be reconstructed.

The kind of photo in #20 works well for troubleshooting, especially if a known-good negative is included as a benchmark. Inverted scans are generally all over the place.

Owlch said:
Also, the negative strip image you worked on was taken on a wide spectrum (high CRI) white light panel, so dye crosstalk for CN was quite significant there.

The light source of the panel you used there really is not the problem.

Owlch said:
crushed shadow or underexposed look

If that refers to the frame numbered #33 that we've seen before: note that the negative itself holds plenty of density differentiation in the area that's 'crushed' in your photo in #22. So at least in part we're looking at problems with your digitization process in post #22.
One problem with that particular frame is that you have a very bright sky and a foreground that's apparently not receiving direct sunlight (it's in the shade of a cloud I suppose), so contrast is high. Exposure erred a little to the side of underexposure, which is not a development problem, but one of metering the scene. Then in the digitization process, what differentiation there was in the foreground was lost in the process; note that there's plenty differentiation (but a crappy color balance) in my very crude inversion.

I think you're battling a cluster of problems and it's unclear at this point to what extent these are potentially related to film processing.

The third example above (the portrait-oriented shot) does in fact look underexposed to be BTW; note the group on the left that drops away into undifferentiated shadows. This may or may not have been intentional. There may or may not be actual differentiation in the negative itself.

Owlch · Nov 12, 2025

koraks said:
I'm sorry, I can't make out anything from those images. They are inverted scans/photos, so what the negative might have looked like cannot be reconstructed.

The kind of photo in #20 works well for troubleshooting, especially if a known-good negative is included as a benchmark. Inverted scans are generally all over the place.

The light source of the panel you used there really is not the problem.

If that refers to the frame numbered #33 that we've seen before: note that the negative itself holds plenty of density differentiation in the area that's 'crushed' in your photo in #22. So at least in part we're looking at problems with your digitization process in post #22.
One problem with that particular frame is that you have a very bright sky and a foreground that's apparently not receiving direct sunlight (it's in the shade of a cloud I suppose), so contrast is high. Exposure erred a little to the side of underexposure, which is not a development problem, but one of metering the scene. Then in the digitization process, what differentiation there was in the foreground was lost in the process; note that there's plenty differentiation (but a crappy color balance) in my very crude inversion.

I think you're battling a cluster of problems and it's unclear at this point to what extent these are potentially related to film processing.

The third example above (the portrait-oriented shot) does in fact look underexposed to be BTW; note the group on the left that drops away into undifferentiated shadows. This may or may not have been intentional. There may or may not be actual differentiation in the negative itself.

I'm still to find out. Currently my plan is to keep everything controlled but using Kodak's kit to do a batch and see. I'll share how it goes once done.

As for the no.33 frame. I agree I'm dealing with more than one thing here. I think it was a combination of development and exposure, although more on the former I reckon.

Grading should be fine, it's just that my workflow is really cruel to underexposure or development problem. Here is one when done right.

koraks · Nov 12, 2025

I suspect in your grading process you may not be taking into account the inherent flexibility of color negative media. It's very different from E6/slides where you have pretty-much a predefined contrast range and color balance. Color negative is inherently more variable - but also more capable when it comes to accommodating a wider range of SBR's (scene brightness ranges). This brings the risk of tailoring an inversion, balancing and grading process on a particular type of negative that represents only a small part of the total bandwidth the process can move in.

Getting more rolls out of C-41 chemistry / aka. Have you tried the Adox/Tetenal/Rollei/Bellini C-41 kit?

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