RA4 fixer part - formula?

[sfaber17]

I have some Kodak RA4 blix that comes in the 2 parts, bleach and fixer that is normally
mixed into blix. The stuff was almost expired when I got it and now after a few months
the bottle of the fixer portion that had been opened turned to sulfur.
It seems to go bad a lot faster than flexicolor fixer (non-RA), perhaps it is more acidic.
How could I make a replacement fixer portion? Help rudi or PE?

 

[Gerald C Koch]

I have the working blix as containing 80 ml of 60% ammonium thiosulfate solution per liter.

 

[Rudeofus]

You face two challenges, one of which is easy, the other one is hard:

1. Get the necessary amount of Ammonium Thiosulfate into your BLIX
2. adjust pH to 6.50

You can use any decent source of Ammonium Thiosulfate, like Rapid Fixer or a bottle of Ammonium Thiosulfate 60% from your favourite chem supplier (Formulary, Artcraft, Suvatlar, Keten, ... depending on where you live), and plan on putting 200 ml/l Ammonium Thiosulfate 60% into your BLIX. This would mean about 250ml of standard Rapid Fixer. Don't even think about wasting money on Ammonium Thiosulfate powder, it's way more expensive and less stable than the 60% solution.

But that was the easy part, as you already know. PE stated on multiple occasions that dyes change their hue with pH, so pH of the last concentrated process liquid can/will have an impact on colour balance. So pH 6.50 it is, which is not easy if you don't have a pH meter. If you have one, use it and be done with it.

Assuming you don't have a pH meter, let's find some important edge cases:

• If pH is above 7, bleaching will be weak
• If pH is below 4.5, you risk precipitating Sulphur from Thiosulfate

Since BX2 is typically Ammonium Thiosulfate plus Acetic Acid (that's why it goes bad so quickly), here is what I would do:

1. Prepare 500ml BLIX from 100ml BX1, 100 ml Ammonium Thiosulfate (or 125 ml Rapid Fixer), rest water
2. Take 10ml from that liquid into a separate beaker and drip some baking soda onto it
3. If the baking soda fizzles, you are slightly acidic and your BLIX is ready to go
4. If the baking soda doesn't fizzle, you are too alkaline and need to add 10 ml Acetic Acid (concentration ideally between 10 and 30%) to your BLIX. Proceed with step 2

This should give you a BLIX which bleaches and fixes, and is at least in the ballpark of pH 6.5.

 

[Gerald C Koch]

I have the following formula for the blix working solution.

Ammonium thiosulfate 60% 80 ml
Ferric ammonium EDTA 10 g
Water to make 1 l

 

[sfaber17]

Thanks all. I did see an old formula like Gerald's and another that had more ammonium thiosulphate.
The bottle says it also has ammonium and sodium bisulphite and ammonium sulfite. I guess it provides the buffering and acts as a preservative. I'd be inclined to add a little sodium sulphite to Rudi's formula. I do have a cheap pH meter and the buffers to calibrate it, and it seems to be good to a tenth of a unit. Your trick (Rudi) to estimate pH reminds me of your nice post on creating separate bleach for C41. This was the Ektacolor RA-4 which mixes 1.4 liters fix part and 2 liters bleach part to water to make 10 liters. The SM version uses equal parts with no water, and doesn't have any ammonium bisulphite, just sodium bisulphite. Maybe the non-SM version is pretty much all 60% ammonium thiosulphate with the added sulphites.

 

[Rudeofus]

Ammonium Sulfite/Bisulfite is more expensive, but also more soluble than Sodium Sulfite/Bisulfite, therefore the less concentrated SM version can use the latter. Yes, do add 10 g/l Sulfite if your RA-4 BX2 component contains it. The difference between Sodium and Ammonium salt should be irrelevant if you mix working solution.

 

[sfaber17]

Makes sense. I was wondering if there was a reason for avoiding too much sodium, but now I think I'll try hit the target pH with a mix of the sodium bisulfite/sulphite.

 

[Photo Engineer]

I have the following formula for the blix working solution.

Ammonium thiosulfate 60% 80 ml
Ferric ammonium EDTA 10 g
Water to make 1 l

Jerry, this can cause severe stain from retained Iron salts. You need excess EDTA to keep the Iron chelated.

A good way to get an RA4 fix part is to use TF-5 from the Formulary mixed at the same volume of that fix as there is in the RA4 blix. This should make up to the right pH as well so there is no fuss about pH.

There was method to my madness when Bill and I designed that fix!

PE

 

[Rudeofus]

Generally you try to stick to Ammonium ion whenever you try to fix film/paper, see the difference in fixing speed between Sodium and Ammonium Thiosulfate. Small amounts of Sodium are of no concern, though, and most Rapid Fixer recipes list Sodium Sulfite/Metabisulfate because these are much cheaper and more available.

I'd say use Sodium Sulfite and Metabisulfite unless you happen to own a stash of Ammonium Sulfite/Metabisulfite. At 10 g/l it won't make a difference.

 

[Rudeofus]

Jerry, this can cause severe stain from retained Iron salts. You need excess EDTA to keep the Iron chelated.

Since sfaber17 will likely use his BX1 part to supply Ammonium Ferric EDTA, there should be the correct amount of excess EDTA in there already.

 

[Photo Engineer]

I recognize what the OP says, but I had to make sure there was no misunderstanding of the formula that was posted.

PE

 

[sfaber17]

A good way to get an RA4 fix part is to use TF-5 from the Formulary mixed at the same volume of that fix as there is in the RA4 blix. This should make up to the right pH as well so there is no fuss about pH.

Wow, it sounds like TF-5 is similar to C41 Flexicolor fixer and the same pH so maybe the Flexicolor fixer is a direct substitute for the RA4 fixer part, and it is quite inexpensive to boot.

 

[Photo Engineer]

Yeah, you can use C41 fixer but it is more concentrated and different IIRC.

PE

 

[Gerald C Koch]

The blix formula I posted appears to be from a set of RA-4 formulas published by Dr Robert Chapman in Photo Techniques magazine. I have added a note that additional EDTA is required.

 

[Photo Engineer]

Many of Chapman's formulas (as are others) are wrong for minor details such as this!

See BP 991,412 for details on EDTA.

PE

 

[Rudeofus]

Just to clear up possible confusion here: Flexicolor Fixer, as well as TF-5, are fixers which operate at pH 6.5 and can therefore be used as "last concentrated bath" in colour processing. RA-4, unlike most other colour processes, uses a BLIX as "last concentrated bath", which means you have to add a lot of stuff to C-41 fixer or TF-5 to turn them into BLIX. Whatever is usually added will alter pH to some extent, and adding lots of Ammonium Ferric EDTA (and extra EDTA as implied by PE) is exactly such a case.

Now we have the special case of BX1 as supplied by RA-4 kit makers, which already has pH very close to 6.5 (Tetenal's RA-4 BX1 has pH 6.7 according to MSDS), and the components of BX1 and fixer do not react with each other (at least initially), therefore we can hope that BX-1 plus TF-5 gives a BLIX at suitable pH. I'd be less confident with some other random source of Ammonium Ferric EDTA.

Since sfaber17 has a pH meter, the whole issue is a lot simpler that initially thought: add whatever rapid fixer you have to make working solution strength, then adjust pH with Ammonia and Acetic Acid. If you see a white crystalline precipitate forming after you added Rapid Fixer to BX-1, don't panic, it's EDTA and will redissolve once you bring pH back up to 6.5.

 

[mshchem]

I'm resurrecting this thread. Same thing happened to me. I don't know when I will learn as this has happened to me a couple times over the years. I opened a 10L concentrate of Blix part A and B. The Fixer salted out sulfur. It is total mess, I wanted to keep going so I just substituted Ilford Rapid fix for the RA4 fixer in the Blix mix. I don't know if the pH was right, everything worked perfectly normal. Why does the RA4 Fixer concentrate, opened,90% full bottle, go bad in 3 months but a bottle of Ilford rapid fix that has been open for over a year stay clear? From now on I'm just going to mix all 10L of the Blix and store working solution in FULL bottles, The Blix is labeled CPAC Imaging, I get it from a old friend that still runs a real camera store. I wish one of you can explain what starts this process, it gets down to 56F at night in my darkroom. Doesn't seem to happen to unopened concentrates. Is it Air/cold/crappy chemicals???

I use Fuji Developer, the concentrates keep forever if you keep the air away.

Best Mike

 

[RPC]

Do you keep it in the original plastic containers? I pour the two parts into filled, glass jars when I buy it. I have some part A that is probably 2-3 years old that is still completely clear, so I would give that a try. I have some C-41 fixer concentrate that is about 7 years old (I got a huge amount from the lab I work at) that is also stored in full, glass jars and is also still completely clear.

 

[Photo Engineer]

I have no idea of the age nor the storage conditions of the fixer part (clear). It should keep for several years.

PE

 

[mshchem]

I have no idea what happened here. First off its some cheap generic CPAC, Bleach/Fix, I use Fuji RA4 developer, the concentrate is like HC110,it lasts forever. This bleach fix, was purchased about 6 months back. I had another bottle of the same stuff do this to me about 2 years back. I think it's just garbage. I'm going to order some Fuji or Kodak Ektacolor RA4 bleach fix.
Then I'm going to split it properly into FULL glass or HDPE bottles, and make sure it doesn't get too cold. I suspect the cool cellar temps may have started the ppt. event and then it just kept going. I've always been a stickler for Kodak chemistry . I remember back in the day, using Kodak rapid fix, w/ the little bottle of hardener. It came in a tall corrigated carton, 1qt of fixer concentrate and the little bottle of sulfuric acid hardener. It made a gallon of film strength fixer, I bet I had bottles of that sitting for years never had anything like this.

Anyway I had fun today refreshing my processing skills, I was making 16 x 20 prints on my beautiful old Kodak Rapid Color Processor, model 16k. I didn't need the prints I am just trying to keep my skills alive. Anyway the Ilford Rapid fix worked, but I am going to order some different chemistry.
Best Regards Mike

 

[mshchem]

I have no idea of the age nor the storage conditions of the fixer part (clear). It should keep for several years.

PE

It was opened in December of 2016, bottle was 3/4 full from the factory, I used enough to make 1 liter from a 10 liter concentrate. Kept in the dark, in a basement darkroom, that probably could have got down to 55F at night. It's some off brand stuff. Cold, along with cheapo stuff seems to be a likely culprit to me.
Best Mike

 

[Wayne]

Is this the same thing that happens with Kodak RA/RT blix?

 

[mshchem]

Is this the same thing that happens with Kodak RA/RT blix?

Now that I read the OP, looks like it. Kodak sells nice little 5 L bottles in the EU. But Its not available in the US.
I don't know what to do.
Mike

 

[Wayne]

Now that I read the OP, looks like it. Kodak sells nice little 5 L bottles in the EU. But Its not available in the US.
I don't know what to do.
Mike

I think if you mix it all up it will keep a lot better. That's what I will do next time. I was using mixed blix from the same bottle of concentrate long after the concentrate went bad.

 

[Photo Engineer]

TF-5 is very similar to both the C41 and RA4 fixer components. They all should keep for about 5 years or so. I have some on the shelf that old that are still OK.

PE