How to choose a C-41 kit (and which ones to avoid)

[00:00:01]Hello, Alex here and in this video I want to talk about how you can choose between the different Myriad C41 film development kits on the market so you can find what works best for you and outright name and shame those that you should not be spending your money on.

[00:00:15]This video was sponsored by Medium Film Lab, the go-to spot for all things film, run by my buddy Khalil at Stuart's Photo in Anchorage, USA. Khalil has been sort of a hype man of mine for a couple years, especially regarding the safety handling and disposal series that I've been working on. So, it's nice to finally partner on something for the greater community. Let's get into it.

[00:00:39]There are a ton of different C-41 film development kits on the market, and it's very hard to parse the differences between them if you don't know what they are. We're talking about liquids versus powders, two bath versus three bath kits, slower kits versus faster kits versus RA kits. How they approach the use and reuse of chemicals in different ways, and how you approach time compensation varies quite a bit. So, we're going to start with the educational side of the video to help you choose from what kits are available in your part of the world before I start pointing fingers. If you're already familiar with the differences between different kits and comfortable choosing between what's on the market and you just want the T, skip to this timestamp for the actual results if that's all you want to see.

[00:01:18]C41 as a process is designed for miniab dip and dunk. You know, large scale process development in a machine with starters to charge the chemicals as soon as you mix the batch and then replenisher to keep them at a steady state over a long time. not mixing a small batch of chemicals and then reusing them with either extended time or whatever else. That is just fundamentally wrong. But once we can all accept that there is no absolutely correct way of doing this at home, but that there are ways that you can do it worse and get worse quality results.

[00:01:51]We're all on the same page there. We're going to be fine getting through this video. I see some people get really hung up on doing it properly and the only proper way to do it is to send your film to a large scale lab. That's just something we have to accept.

[00:02:07]People are generally very split on this.

[00:02:09]Some kits either come with sachets of powder that you you know dissolve up to make your working solutions and other come as one or more liquid concentrates for each developer component that you then dilute to make your working solutions. The main advantage in terms of uh powders is their shelf life. A dry well stored powder can last years to decades. It's not the same thing as fil color film development, but I've used sachets of ID11 which are older than me and still working just fine because they are anhydrous dry powders stored cool over the years. Some chemicals just inherently go bad over time. That's a different thing. Once you dissolve these chemicals in any amount of water, I mean water is the universal solvent. It facilitates most chemical reactions that we're familiar with on Earth, at least in the liquid phase, which means that any amount of water is going to slowly facilitate the degradation of these photochemicals. And the more dilute they are, the faster that happens. That means that once you dissolve either a uh a powder kit or a liquid kit into making your working solutions, you know, your one liter or two and a half liters or whatever, they will more or less start to go bad at the same rate because they're at the more or less same concentration. But powders longterm on the shelf keep a lot better than liquids do, but liquid concentrates still can last a very, very long time. The main advantages for using liquid developers are splitting or portioning as well as safety. If I want to use half of this kit to make two 500 mil solutions with the sin still kit, good luck to me. It's like if you have a jar of marbles and you put some sand in there, no matter how much I shake that packet, the second I stop, the smaller particles are going to start settling out to the bottom.

[00:03:44]Meaning it becomes effectively impossible to accurately, precisely, and reliably split the kit. Whereas there's what 500 mil in this color developer part A from the Holy Color Cam kit. I can just put that in a graduated cylinder and make 250 mil and 250 mil or five 100 mil batches using that. No problem. But with a powder, that's not something you can really do. Some people have tried it. Some people have gotten lucky and gotten good results, but as a rule, you cannot properly split a powder kit where you can split a liquid kit.

[00:04:14]The other thing is safety. Powders inherently liberate dust into the air.

[00:04:18]Adox in Germany with their black and white developers have made a big deal of their captura technology which to their credit does absolutely make the dust less dusty reducing the fine particles being dispersed into the air getting into contact with your mucous membranes your eyes and your lungs and your mouth.

[00:04:34]And these chemicals, let's be real, they are, you know, safe enough to be sold for home use. But if mishandled, like if you get them in your eyes and mouth or on your skin are harmful. They will cause skin irritation, sensitization, potentially cancer or direct corrosion depending on the chemical and the level of exposure over time. The likelihood of exposure is greater with a powder kit than with a liquid kit, but the risks are more or less the same once you do get them on you with some limited exceptions. Broadly speaking, liquid kits are safer to handle.

[00:05:10]We just spoke about the shelf lives of powders versus liquid concentrates. But the working solutions are a different thing. Different manufacturers give vastly different rules on how long these chemicals should be kept. Some saying 3 to 4 weeks. Many people online saying they keep their chemicals for 3 to 6 months, no problem. But notably the Kodak Flexi color kit, one of the newer ones on the market that people take as like a gold standard cuz it's the Kodak one, um say to keep the color developer for only one week after mixing it. In theory, these things are all the same.

[00:05:38]So, in theory, it's about the same. And this is again one of those things. It's just a matter of how wrong is acceptable for you. The second you mix it, the chemicals start to go bad. How soon you notice it and how soon it affects your results in a meaningful way is going to be very personal. If you are shooting 50 rolls of portra for a wedding, you're going to want high quality, consistent results. So, you're going to want to do it all very quickly so the negatives look the same, so they scan the same for a consistent look. If you're more of a take the extreme polar opposite, you know, a film super who deliberately damages and harms their film for creative effect. Don't get me wrong, it's not my taste, but it's a very cool field within photography. Those people are going to be more tolerant of things like a color shift from the color developer aging more. The point being that the sooner you use up the chemical batch once you've mixed your working solutions, the better your results are going to be. How long is acceptable?

[00:06:34]There is no strict answer. It's like if I boil a ham today for dinner and I have some slices left over I want to use for a sandwich tomorrow. Is it acceptable to use them tomorrow? Is it acceptable to use them in two days time if I keep them in an airtight container in the fridge?

[00:06:49]Some people will say absolutely not.

[00:06:51]Other people will say yeah it's completely fine obviously but that ham is definitely going bad in those couple of days. It's just a question of when it becomes unacceptable in terms of quality. Personally, I subscribe to using all of my C-41 chemicals within usually two weeks if possible, three at a figurative, not lateral push, and my ECN2 chemicals within a week maximum for best results. That does depend on what you're doing, though. Like, if I'm developing expired film or found film or just stuff from friends in a point and shoot, I don't mind using chemicals that are maybe 3 or 4 weeks old for C-41 because I know they're going to work.

[00:07:28]They're just not going to be at their peak. But when I'm doing my film testing, I want consistent, fresh chemicals to be used. So, I want to do things in as short a time frame as possible. Again, this is all very personal, and it depends on your needs.

[00:07:42]There are some exceptions with different brands, but broadly speaking, there are three sizes of C-41 kit. One liter, 2.5 L, and 5 L. Larger kits can develop more film. That makes sense. And they are more expensive, but they are not more expensive per liter. They work out quite a bit cheaper. If you're not sure, chances are a one liter kit is going to be the right answer for you. But there's also the fact that, you know, labs charge different rates in different places. For me, a C-41 kit breaks even after about six to eight rolls depending on which lab I look at. Other people in certain parts of the US in particular for C-41 development, it's not cheaper unless you buy like a 5 L kit. So then it would only if you wanted control or alternative processing methods that it would actually be worth doing that. With larger volume kits, it also becomes economical to use your chemicals one shot, meaning you use them one time and you throw them away with and that is more wasteful. But as you'll see in a second, that is closer to the C41 spec, even though it's still wrong. That's what I do. I use 2.5 L kits and that lets me fill something like this Joel 1540 tank with 470 ml of developer solution and develop up to four rolls of film.

[00:08:49]But that is catastrophically wrong for C41 specification. And yet it completely works. I want to keep driving this point home that we're all doing it wrong and it's clearly fine. The C-41 specification says that you can develop only four rolls of 35 mm film or equivalent with one liter of developer.

[00:09:07]That's all. With HomeKits, we are taking that working solution and then reusing it by extending the development time to compensate for loss of developing power as well as accumulation of crap from the films into the developer. I mean, if you've ever developed film at home, you've seen developers change color. You know, there's stuff coming out of the film into it. Kodak say you can technically only develop four rolls with a liter. We can do many, many more than that, but the capacity per liter of a kit varies wildly based on manufacturer recommendations. Many stick to the sort of 10 to 16 roll range, 12ish being quite a normal number, others recommending 20 or beyond. The more you reuse those chemicals, the worse your results are going to be. There is no denying that. There is no arguing that.

[00:09:52]But that doesn't mean that for your setup, for the films that you shoot, and for your scanning setup that those changes and degradation in the quality of negatives will actually be noticeable or be a problem. You know, it's fair to accept that a kit will give you imperfect results if you use it for 12 rolls. The 12th roll will definitely be a a less high quality negative than the first or second roll. That doesn't mean it's going to be bad or unusable, though. These kits again should all be the same stuff, but they are not literally identical to the nth degree.

[00:10:20]So, some variance is expected, but I would lend credence to the fact that 3 minutes 15 seconds is actually the base time. And that sinest, for example, are the odd ones out there. And almost everybody agrees on that 3 minutes 15 seconds plus 15 seconds for every four rolls kind of reuse methodology.

[00:10:37]Everyone is wrong, but if most people are doing one thing, that probably works really well.

[00:10:44]So far, I've been focusing on the developer solution, but there's a distinct split in the bleach and fixer steps as well. The C-41 process, just like black and white, uses a developing solution to develop the silver in the film. That there is silver in color film, just like with black and white.

[00:10:59]And the byproduct of that is the formation of the color dyes. The silver is just a means to an end. Then we use a bleach to reoxidize the developed silver back to silver salts so that the fixer can remove all of the silver at the end.

[00:11:11]A standard three bath kit has a developer, a bleach, and a fixer as three different baths that you would use, and it's just three different steps. But many kits combine the bleach and fixer into what's called a bleach fix, hyphenated, or just blicks. Most affordable kits are like that. The sinest kit, the addu kit, and so on, all use a two bath method. The main advantage of a two bath kit is just that it's simpler. You're doing two baths instead of three. That's a simpler overall process, and a lot of people like that. Free bath kits tend to be faster with the bleach and fixer acting generally speaking more quickly, especially at the end of the kit's life where a blick can take upwards of 10 to 15 minutes, which is just woefully slow.

[00:11:50]Okay, I use a rotary processor, so a machine spins my tank for me. But if you're sitting there doing this every 15 or 30 seconds, depending on your method, that gets very tiring very quickly. Time isn't the only thing though and blicks inherently have a shorter shelf life than bleaches and fixes that are made separately. Okay, the developer is usually the limiting factor there. But generally speaking, you can get C41 monopart developer from some vendors in some countries, which means that if your developer dies, you can just buy separate developer and keep using the bleach and fix or blicks that you have to hand. But Blick's shelf life is not as good. In simple terms, you know, bleach is an oxidizing agent. It's the same as it's not the same chemical, but it's the same principle as household bleach for cleaning. And even though we don't use a fixer as a reducing agent, they are reducing agents that can be oxidized. And those two things are fundamentally at odds, meaning that the ble the blickes kind of slowly wear themselves down over time and their shelf life just isn't as good. I'm re-recording this part while editing because I feel like I overexlained it to the point of confusion the first time around. When you have a two bath kit, the blicks, the combined bleach and fixer cannot be desered for to make it safe for disposal like a normal C-41 fixer or a black and white fixer can using the steel wool, which will have implications in certain parts of the world for disposal. You know, if you have a recycling center, it's probably not going to be a big deal. But if you dispose of your fixers and developers at home and you want to render this stuff safe, you simply cannot do it with a two bath kits blicks just using steel wool, which might be a big point for some.

[00:13:21]There are a couple of other things to be known about blicks like you can't bleach bypass your film because you have bleach and fix in the same thing. You can't just directly fix without a bleach. And there's also the very subtle thing about how um a two bath kit with a blick technically doesn't remove all of the silver from your film because the fixer is slightly more potent than the bleach.

[00:13:38]Not all of the silver gets bleached away, but the fixer does strip out all of the bleached silver. In theory, that leads to slightly reduced saturation, slightly increased grain, and slightly increased contrast compared to a three bath kit. I've never done a sidebyside, so if that's something that people think is worth me looking into, let me know.

[00:13:57]And now we get to the spicy part of the video. I've alluded to the fact that these kits should all be the same thing, but technically strictly aren't. You know, maybe EDTA is cheaper than PDTA in Italy versus America. Or maybe there's a certain sulfide salt that's easier to get a hold of in South America than in uh North America. So, you work with kind of what you have and they fit the same overall fundamental purpose, even if the formulations are slightly different. At its core, a C-41 kit is built with three things. A developer solution built around color developing agent 4. This is a paraphenolene diamine derivative that has a very particular structure and is vital for developing color film because it is as I mentioned used to develop the silver in the film and then this byproduct forms the actual color dyes that make up your final image. The second thing is a bleach based on either fericmonium EDTA or fericcommonium PDTA.

[00:14:48]This is what oxidizes the developed silver back into silver salts that the fixer can remove. And then finally a very mildly acidic rapid fixer solution based on ammonium viulfate. These are the core chemicals that make a C-41 kit what it is, particularly the color developing agent 4. And like I said, some variation is to be expected and is completely acceptable. The ADOCE kit is a two bath liquid concentrate kit using CD4 as the developer, fericcommonium EDTA as the bleaching agent, and ATS as the fixer. So, it's a great all-around kit. Kodak's Flexiolor kit is a three-bath liquid concentrate kit using CD4, Fericmonium PDTA, as well as ATS again. So, this is a top tier kit, no questions asked. Sinestyl C-41 kit is available either as a powder kit or as liquid concentrates. Same formulation either way using CD4 as the developer, Fericommonium EDTA and Fericcommonium PDTA, and then ATS is the fixer. It gets a fine rating here rather than a great rating like the other two bath kits because there are so many reports of this kit just suddenly dying with a much shorter unexplained shelf life. There are theorized reasons for why that might be the case that I won't go into because they are just speculatory at this point, but it is known that this kit is somewhat more likely to just randomly stop working than other two bath kits.

[00:16:02]If you're going to use it very quickly, I would have no hesitation about it within a few days to a week. If you're the kind of person who wants to keep your C-41 kit for a month, go for something like the Adox kit or the Holly kit rather than the Sinest one. Holy Color Chem kit is a two bath liquid concentrate kit using CD4 as the developing agent. Vericmonium PDTA is the bleach and they don't actually specify the fixer in their SDS because they don't have a fixer section, but we're going to assume it's ATS. And I've used this kit many, many times over the years, so it's perfectly good. Dooo's 9240 C41 kit is a three bath liquid concentrate kit using color developing agent 4, fericammonium, EDTA, and ATS.

[00:16:36]So again, top tier just for large volume shooters. Similarly available for large volumes, the Fuji Hunt Express kit is also a three-bath liquid concentrate kit using CD4 fericmonium PDTA and no specified fixer but probably ammonium thiofate. So it's a great fantastic all-around kit as well. The Bellini C41 RA kit is a three bath rapid access kit using liquid concentrates though with a monopart developer rather than separate AB and C using CD4 as the developing agent, fericammonium PDTA as the bleach and ammonium thiocyanate as the fixer.

[00:17:07]Ammonium thiocyanate is an alternative fixer used in some alternative processes. It's just an extremely rapid fixer beyond the typical ammonium thulfate rapid fixer that we're used to.

[00:17:18]There's no problem there. Everything so far is more or less on equal footing. It just depends on the size of the kits, whether you want a one liter kit or a 5 L or a 2.5 or 1.2 or whatever and whether you have a preference between a two bath kit and a three bath kit. From here on is where I would start being careful about where I'm spending my money. The film photography project's so-called C-41 kit is a two bath kit using powders with CD3 color developing agent 3 as a developing agent, potassium ferocyanide as a bleach, and sodium thiofate as the fixer. I'm sorry, that is literally an ECN2 kit. The CD3 is the developer used for E6 and ECN2 processes. If you use a different developing agent, you're going to get different colors because your absorption patterns will change. You are cross-processing the film when you're using CD3. On top of that, you're using potassium ferocyanide as the bleach.

[00:18:08]That's your standard ECN2 bleach, which isn't inherently a problem, but there's no stop bath and no recommendation to use a sulfite clearing bath either. Stop bath being the bare minimum. So, you're more likely to see color streaking with the formation of Prussian blue getting carried over into the developer. You don't need to know what I'm talking about. You just need to know that that's a problem that this kit doesn't account for. This kit is a perfectly fine ECN2 kit if you add in a stop bath yourself.

[00:18:32]But to call this a C-41 kit rather than a color development kit for ECN2 and C-41 film, you see the difference there is disingenuous at best. The FPP actually also sell the Unicolor C-41 kit where you can just see that it's straight up more expensive. The chemicals to make a C-41 kit are more expensive than those to make an ECN2 kit. And this is just misleading. What Flickilm call their professional C-41 kit is a three-bath kit which is mostly powder-based but with a liquid fixer using paraffhenylene diamine as the uh developing agent, potassium ferocyanide as the bleach and then ammonium thioulfate as the fixer. This is a nightmare. Not only is it using potassium ferocyanide, though they do give you a stop bath, so you know you're less likely to get color streaking.

[00:19:16]Still not proper C-41 bleach.

[00:19:19]paraphenylene diamine really really not even CD3 not even the old deprecated CD2 and CD1 these developers are all paraffhenylene diamine derivatives which is to say that you know there is a paraffheneline diamine structure contained when the overall molecule but that doesn't mean that they behave the same or can be used the same way I mean that's like calling a cookie a form of flour there are transformations and things that happen when you amalgamate the different components together that change the overall properties. Cookie crumbs don't behave like flour in the same way that CD4 does not behave like paraffhenylene diamine. That is completely unacceptable. There is also the eco-friendliness angle where Flickfilm talk about how their kits have 38% less chemical I believe than a standard C-41 kit. And they talk about this quite a lot in their marketing material. And what's worse is the Flickilm eco kit which is also a three bath kit all powder this time still using paraffhenine diamine as their so-called developing agent. Potassium ferosinide is the bleach and ammonium thioulfate. And this time they don't even give you the stop path of the stabilizer. So they say you're getting 53% less chemical usage compared to a normal kit instead of 38 by just giving you less than the professional kit by just taking bits out. It's like making a low sugar cookie by taking all the chocolate chips out and then saying it's, you know, better for you. Like yeah, kind of. Regardless of where this 38% comes from to begin with, whether it is the potassium carbonate and ammonium bromide, which it might not be, those are just easy targets for me to assume they're reducing their chemical usage in the C-41 developer formula and bleach.

[00:20:52]The fact that they're using paraffhen diamine at all is inexcusable. It is, you know, a cardinal sin if you want to take it that way. It is a gross abuse of people's trust. And what's worse is that if you look at the link on their page, the C41 kit that they use in their few year old YouTube video contains CD4, meaning at some point they have changed to paraphenolene diamine. This is completely unsuitable. Paraffenoline diamine sure has some level of color development activity and yes it can couple with the dieouplers but it is the structure of the die of the oxidized developer that gets incorporated with the dieoupler that determines the overall properties of the die molecules.

[00:21:31]And by changing that, you are changing the final results and compromising on quality just to save a buck. I have a chest infection as I'm recording this, so I'm just doing voice over. And you can look at these STS screenshots here.

[00:21:42]But I want to give a major caveat to what I've just said, even though I've decided to leave it in the video. As of at least a couple of weeks ago, you know, one to one and a half weeks after I actually recorded this video, which is really annoying. The SDS files on the Flick Film website now linked to updated documents which say they're using CD4.

[00:21:59]Again, that is great. It's good that they are again using the correct color developing agent 4 for C-41 film, but honestly given what they have done for up to four years between June 2026, which you can see in the URL on the SDS files on their website and June of 2022 when they released the C-41 how to mix video, any amount of time within that period, they've been selling C-41 kits using PPD instead of C41 uh CD4. And honestly, I don't trust them not to do this again. So, I don't recommend their kits, even though they're now doing the right thing. The vast majority of people out there probably have experience with inappropriate kits. So, I think it's fair to leave in what I have said so far, whilst adding in this caveat that they are apparently doing things properly. Now, when it comes to the different C41 kits on the market, whether you're choosing a two bath kit or a three bath kit is to a certain degree down to personal preference. I would personally take a three- bath kit any day, but I wouldn't judge people for taking a two bath kit as long as you're aware of the worst shelf life and the inability to properly bleach bypass. Certain kits do have compromises in terms of their shelf life, like the Sinestl kits being known to not last as long as the others for whatever reason, but the overall methodology is fine. It's just a matter of how many rolls and how long of a shelf life are acceptable to you. And honestly, there is no answer. just use it as quickly as you can for as many rolls as you seem to be happy with. And that's all you can really do. You know, trying to stretch every last possible role of development out of a C-41 kit is just going to give you terrible results at the end. I know one guy who's developed over 40 rolls with a one liter kit and the negs look terrible. There's almost nothing there. There's almost no color information and the photographs look accordingly trash. I'm sorry. That is not proper C-41 development. If you care at all, you should treat your photos with some level of respect and not try to absolutely minmax your costs.

[00:23:56]There's a certain point beyond which you're not actually saving money by reducing your costs. It's all more or less the same. Just pick what's available to you as long as it meets the volume in terms of, you know, liquid solution, one liter, 2.5 liter, and the resulting capacity and shelf life that works for you. And maybe it's not worth developing C-41 film at home. For a lot of people, it isn't. You know, C4:1 being standardized is the only reason that it's economical to do in labs like medium film lab to begin with, which means that you can get great, consistent, highquality results at a lab very affordably by comparison to black and white film. But that does mean that it's a lot harder to make it economical to do at home. But what is not personal and subject to opinion is that the FPP do need to be a lot more honest with their marketing. if they were to brag about how they have one color kit that you can use for both C-41 and ECN2 film, that would actually do really well. A lot of people would flock to that. A lot of people cannot tell the difference between cross-processed film, C41 film in ECN2 developer or ECN2 film in the C41 developer, as is the case with Sinestl, because when you're scanning, a lot of this stuff gets corrected away anyway, and it only really matters for color critical work or if you're going to be RA4 printing. In fact, one of my friends recently bought one of these kits as a C-41 kit and it straight up has the ECN2 label on the package. So, there you go. Under no circumstances can I in good faith recommend anyone spend money on the flick film kit. Not only or either of them, not only are they using a grossly inappropriate so-called developing agent, which yes, technically is a developing agent, but is not a C-41 film developing agent. You might be able to use it for C41 film. Not that many people get great results with it. that I've seen more complaints than, you know, praise of that particular those particular kits. The only possible benefit of the doubt I can give Flick film here is that they've realized that because most people are not RA4 printing their color negatives, the differences are made up for in scanning and that you can recover detail from them, allowing them to reduce their costs and m remain competitive in a highly competitive economic environment. Sure, they have gone way too far if that's the case.

[00:26:04]Regardless of the reason PPD should not be there in place of CD4, I'd like to thank Medium Film Lab for sponsoring this video and for working with me. Kill is a good friend of mine.

[00:26:16]We were both featured in Alaska Business Magazine in an article not too long ago.

[00:26:20]So if you ever find yourself in or near Anchorage, Alaska, make sure to stop by Stuart's photo and say hi to Khalil at Medium Film Lab. Their broad range of development options, including slide processing, pushing and pulling, and even renjet removal for ECN2 film cross- processing, which most labs won't even consider, are paired with 6K scans in any format you'd like. Kal also hosts photo walks from time to time and even day trips and multi-day film photography courses scheduled after business hours so working professionals can get in on the fun, too. I hope at this point you feel more confident in picking between the different C-41 kits on the market and realizing that they all do fundamentally serve the same purpose and they're going to do the same thing and you're kind of doing it wrong by doing it at home anyway. So, the differences don't matter that much. Certainly, I hope you feel more confident in picking between a powder versus liquid kit or a two bath versus three bath kit and that you're aware of which kits you should be wary of spending your money on and which kits you should absolutely not be giving your money to.

[00:27:15]So, thanks again to Khalil and Medium Film Lab. That's all I have to say for this video, but stay safe and bye-bye for now. If you don't already, follow me on Instagram @ shak1277 [music] for new pictures every day. If you like this video and enjoy what I do on the channel, please consider subscribing or [music] checking out my Patreon where the tiers start at just €1 per month.