Selecting a good C-41 kit / Separating blix into bleach & fixer.

[dcy]

Hi everyone,

I've been lurking the forum for some time. Now I want to ask a couple of questions. I was reading a thread from last year. In this comment koraks says that he considers powder C-41 kits to be second rate and "all quality C41 chemistry comes as liquid concentrates." A little later he explains that the issue is that they are blix-based kits (i.e. they don't have a separate bleach + fix).

Question 1: I am familiar with the problems with blix. Aside from that, is there any other downside to powder kits? The reason I ask is that the Rollei, Arista, and Tetenal (now reborm as Adox) C-41 kits are all liquid kits that have a blix instead of a separate bleach + fix. In other words, I am wondering if all of those options are equally sub-optimal.

Question 2: "Blix" usually comes in 2 or 3 parts. Can I just... not mix them and treat them as a separate bleach & fix? To attempt this, I need to figure out which part is the bleach and which one is the fixer. The Rollei and Adox/Tetenal kits have a blix in 2 parts. If you read the MSDS you'll see that:

1) For Rollei, Part 1 has a "European waste catalogue" of "bleach solutions and bleach fixer solutions" while Part 2 says "fixer solutions".

2) For Adox/Tetenal, "Ammonium thiosulphate" is listed under Part 2, so that must be the fixer. Part 1 includes a molecule with a long complicated name that looks like a cousin of PDTA and EDTA which usually is part of the bleach.

So I could keep Parts 1 and 2 separate and add water to each. Because bleach and fix are both "to completion", I can be conservative and leave the film in each bath for a few extra minutes.

Would this strategy work?

Thanks for the help.

 

[koraks]

I was reading a thread from last year. In this comment koraks says that he considers powder C-41 kits to be second rate and "all quality C41 chemistry comes as liquid concentrates." A little later he explains that the issue is that they are blix-based kits (i.e. they don't have a separate bleach + fix).

That's part of it. The other part is that the powder-based kits usually consist of a non-standard developer (e.g. Cinestill Cs41). If powdered chemistry would be a feasible option to get lab-standard quality, the industry would have adopted that decades ago. The fact that they settled on (usually) 3-part liquid concentrates indicates that this is really the only feasible way to provide consistent and excellent results at reasonable costs.

You could theoretically make a powdered kit that would perform to spec, but it would involve packaging and mixing challenges that would not work well for amateur/home lab settings.

So my main concern is really with the developer in these kits. The blix is a secondary issue.

Can I just... not mix them and treat them as a separate bleach & fix?

Many people have done this and to the best of my knowledge with good results. The main concern would be that you may not hit the perfect pH for the bleach, but as you said, that is supposed to go to completion and besides I'm pretty sure it has considerable leeway in terms of pH anyway, I wouldn't worry too much about it.

You could always do a test to see if it works well for your process. Take an unexposed and unprocessed strip of color film. Run that through your color fixer (or even a B&W fixer). It should clear into a typical orange CN base. Now take a strip that's entirely fogged (daylight is fine), then develop it in a B&W developer (print developer is OK). Then run it through your separate bleach and fix steps. This strip of film should have virtually the same base density as the control strip that you only ran through the fixer.

Because bleach and fix are both "to completion", I can be conservative and leave the film in each bath for a few extra minutes.

Yes, that's right.

 

[khh]

The kits with separate bleach and fix aren't much more expensive, though. In your shoes, I'd just get one of those, that's what I've done. Kodak's, Jobo's, Bellini's and Fuji Hunt X-press are all excellent.

 

[Truzi]

This resource posted by Rudeofus may prove helpful:

Converting C-41/E-6 BLIX into Separate Bleach and Fixer

1 Introduction Many C-41 and E-6 kits come with BLIXes to remove silver. These BLIXes sometimes don't work all that well, and some of the BLIX concentrates have limited shelf life. The main purpose of this document is to provide a brief...

www.photrio.com

 

[blee1996]

There are plenty of liquid C41 kits that have separate Bleach and Fix, for example the resurrected Kodak C41 kits that's inexpensive and available everywhere in the US.

 

[dcy]

That's part of it. [ ... ]

Thanks! That was really helpful.

 

[dcy]

The kits with separate bleach and fix aren't much more expensive, though. In your shoes, I'd just get one of those, that's what I've done. Kodak's, Jobo's, Bellini's and Fuji Hunt X-press are all excellent.

Kodak, Jobo, and Fuji Hunt are 2.5 - 5L kits. I have never developed C-41 and I only shoot about 1 roll/week (or slightly less) including B&W and C-41, so I am concerned about the C-41 chemistry going bad. So I'm mainly looking at 1L kits.

Bellini makes a 1L kit and basically I am torn between Bellini and Adox. They cost about the same ($44 vs $38.50 from Freestyle photo) and both make 16 rolls, which is the most I think I can manage.

As you said, Bellini has separate bleach + fix. My concern, again, is longevity. Bellini gives you a pre-mixed bottle of developer concentrate. They say that an open bottle of developer concentrate is good for 4 weeks.

In contrast, Adox keeps the developer in the usual 3 parts and they say that the unmixed-but-open bottles are good for 12 weeks. That gives me a lot more flexibility to arrange development sessions without the developer going kaput. So that's why I'm eyeing Adox.

 

[koraks]

You can keep most c41 developer for a very long time mixed working strength and stored in airtight containers. This means glass or something like PET or the kind of bladders used for wine. It's important to ensure there's no air on top of the liquid in the container. I keep my Fuji Hunt C41 developer fresh this way for well over a year.
My film consumption isn't all that much higher than yours btw.

 

[dcy]

This resource posted by Rudeofus may prove helpful:

Converting C-41/E-6 BLIX into Separate Bleach and Fixer

1 Introduction Many C-41 and E-6 kits come with BLIXes to remove silver. These BLIXes sometimes don't work all that well, and some of the BLIX concentrates have limited shelf life. The main purpose of this document is to provide a brief...

www.photrio.com

Wow. Thanks! Yes, that looks super helpful.

 

[blee1996]

Air-tight and light-tight aluminum foil lined wine bladder (pouch) can keep mixed C41 chemical fresh for years. I have done that for larger 2.5L/5L kits.

 

[dcy]

You can keep most c41 developer for a very long time mixed working strength and stored in airtight containers. This means glass or something like PET or the kind of bladders used for wine. It's important to ensure there's no air on top of the liquid in the container. I keep my Fuji Hunt C41 developer fresh this way for well over a year.
My film consumption isn't all that much higher than yours btw.

Thanks for the tip!

I know the glass bottles you're thinking of. I use them for B&W chemistry. I'm going to grab a few more and I will also buy one of those inert gas products people use to displace oxygen. I'm going to start with the Bellini kit, and if I manage to not screw up the developer, I will aim to eventually move to one of the 2.5L and 5L kits from Kodak and Fuji.

 

[mshchem]

Thanks for the tip!

I know the glass bottles you're thinking of. I use them for B&W chemistry. I'm going to grab a few more and I will also buy one of those inert gas products people use to displace oxygen. I'm going to start with the Bellini kit, and if I manage to not screw up the developer, I will aim to eventually move to one of the 2.5L and 5L kits from Kodak and Fuji.

This sounds like a good strategy.

 

[koraks]

I will also buy one of those inert gas products people use to displace oxygen.

I don't use it and frankly, I don't put much stock in it either. The 'seal' this creates is very imperfect and temporary. A more dependable strategy is to buy relatively small bottles (e.g. 300ml or so) and ensure they're entirely full until you open one to use it up.

 

[dcy]

I don't use it and frankly, I don't put much stock in it either. The 'seal' this creates is very imperfect and temporary. A more dependable strategy is to buy relatively small bottles (e.g. 300ml or so) and ensure they're entirely full until you open one to use it up.

I can do that! Thanks.