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

[Photo Engineer]

Thanks Matt. I don't track these links as it is just too much for me and I have many of them in hard copy or personal notes.

PE

 

[Kuby]

Hello,

Being in Canada and having limited availability to some of these products, I have a few questions.

I use the Unicolor C-41 kit.

Stop Bath
As I understand I don’t need a stop bath between the CD and the bleach. Correct? If I need a stop bath, can you direct me to a product or solution I can make?

Bleach
Blix B bag contains Sodium Ferric EDTA
Must add Ammonium Bromide to make bleach more active (50-100g per 1000ml of solution)
Mix the whole thing at once
Am I missing anything?

Fixer
I need a fixer of PH between 5 and 6.5
If I use a product such as this: https://www.bhphotovideo.com/c/prod...1296_Clearfix_Neutral_Rapid_Fixer.html?sts=pi and correct PH balance to within working range with acetic acid, will it work?
If not, can you direct me to a product that would work that is currently available? I tried some of the original products listed in the original article, but none of them are available to me.

Thanks!

 

[Photo Engineer]

Use C41 fix or TF5.

PE

 

[Kuby]

Use C41 fix or TF5.

PE

This stuff? https://www.bhphotovideo.com/c/prod...mulary_03_0200_TF_5_Archival_Rapid_Fixer.html

Sorry I just want to make sure. I also want to say thank you PE for the immense knowledge you share on this forum. I avidly read and am a first time poster.

 

[Photo Engineer]

Yes, that is the right TF5 and thanks for your comment.

PE

 

[Paul Verizzo]

You'd think that every variable or question possible would have been asked by now. But, no...........

I got my Rollei Colorchem kit (the six bottle one, not the relabeled Fuji stuff) and mentally delved into making the bleach and fixer separate from this thread. The MSDS only lists four "nasties," chems that need to be identified. Using the CAS numbers when necessary, one a potassium hydroxide solution, one is a potassium carbonate solution. There is no cross identification with bottle name or purposes. (Which you would think would be really, really, like, helpful in an accident?)

Then comes CAS 2809-21-4, Etidronic Acid at 2-5%. Never heard of it! What is its purpose?

Finally, CAS 139-89-9. An extremely long name I won't waste time copying, one source says it's proprietary. A shortened name is Trisodium HEDTA. The bleach, I presume.

Any comments on that as a bleach, generally? And using it separately? Maybe not a good idea?

 

[AgX]

There is no cross identification with bottle name or purposes.

There is.
The "nasty" stuff is listed per bottle.

Finally, CAS 139-89-9. An extremely long name I won't waste time copying, one source says it's proprietary. A shortened name is Trisodium HEDTA. The bleach, I presume.

No.
Not a bleaching substance. It is not of the Redox-type.
I assume it is employed as alternative to complexing EDTA. It is part of the developer.

 

[Rudeofus]

Etidronic Acid is also known as Dequest 2010. It's a powerful sequestering agent for iron and copper ions, and I would assume it is contained in the color developer (or first developer in case of E-6).

In some commercial bleaches I have seen multiple iron chelating agents, and this EDTA lookalike appears to be one of them, but most likely not the only one in there.

 

[Paul Verizzo]

There is.
The "nasty" stuff is listed per bottle.



No.
Not a bleaching substance. It is not of the Redox-type.
I assume it is employed as alternative to complexing EDTA. It is part of the developer.

I presumed that. My question was more on the order of "What now," referring to the purpose of this thread.

 

[Paul Verizzo]

Etidronic Acid is also known as Dequest 2010. It's a powerful sequestering agent for iron and copper ions, and I would assume it is contained in the color developer (or first developer in case of E-6).

In some commercial bleaches I have seen multiple iron chelating agents, and this Etidronic Acid appears to be one of them, but most likely not the only one in their.

thanks, of course!

 

[Paul Verizzo]

@AgX "There is.
The "nasty" stuff is listed per bottle." No, it isn't. Neither on the bottles, nor crossed to any bottle on their MSDS.

 

[AgX]

Then we both got different MSDS. I looked at those on the Macodirekt site.

 

[Rudeofus]

@AgX "There is.
The "nasty" stuff is listed per bottle." No, it isn't. Neither on the bottles, nor crossed to any bottle on their MSDS.

Paul, the MSDS supplied on the Macodirekt site is a 46 page document, and the first 8 pages are for CD part A. These first 8 pages list the four compounds you mentioned. Therefore I have to correct my prior posting: Trisodium HEDTA works together with the Etidronic Acid to sequester iron, copper, calcium, magnesium and a whole range of other metal ions which cause either scaling or premature developer oxidation. Neither of these two compounds are used in the BLIX.

 

[Photo Engineer]

Etidronic acid is not exotic. https://en.wikipedia.org/wiki/Etidronic_acid

A very common medication.

PE

 

[Paul Verizzo]

Etidronic acid is not exotic. https://en.wikipedia.org/wiki/Etidronic_acid

A very common medication.

PE

How about that. 72 years old, always dabbling in science, never came across it. Certainly never in regards C-41 chemistry.

 

[Paul Verizzo]

Paul, the MSDS supplied on the Macodirekt site is a 46 page document, and the first 8 pages are for CD part A. These first 8 pages list the four compounds you mentioned. Therefore I have to correct my prior posting: Trisodium HEDTA works together with the Etidronic Acid to sequester iron, copper, calcium, magnesium and a whole range of other metal ions which cause either scaling or premature developer oxidation. Neither of these two compounds are used in the BLIX.

Wow, must be that Euro bureaucracy that conservatives on this side are always screaming about. Even ours here is too long unless you want to read to go to sleep. Thinking of the reason for MSDS's, in the event of spills, fires, etc. "Hold on here, I'm only on page 25.........."

The Rollei MSDS here is written up by Calbe Chemie, appears to be a German firm.

The bottom line per this thread's purpose is that I really don't know what I'm dealing with in the blix. The bleach part is a deeper red than I've ever seen in the Unicolor kits.

 

[Photo Engineer]

Paul, it is basically Fosamax or something similar.

I worked with these chelating agents for years.

PE

 

[Rudeofus]

Now that I take a closer look at the MSDS, the BLIX is very odd: BLIX part A contains 10-15% of a compound with CAS number 111687-36-6. This compound is also called "Ammonium Ferric PDTA" and is the compound used in Flexicolor Bleach III. This compound is more powerful than Ammonium Ferric EDTA, and until now I was not aware that one could make a stable BLIX with it. Since this MSDS carefully avoids listing compounds it doesn't have to, I can't tell whether there is also Ammonium Ferric EDTA in BLIX part A of this product. Is it a very thick red liquid? What does the BLIX look like?

 

[Paul Verizzo]

Now that I take a closer look at the MSDS, the BLIX is very odd: BLIX part A contains 10-15% of a compound with CAS number 111687-36-6. This compound is also called "Ammonium Ferric PDTA" and is the compound used in Flexicolor Bleach III. This compound is more powerful than Ammonium Ferric EDTA, and until now I was not aware that one could make a stable BLIX with it. Since this MSDS carefully avoids listing compounds it doesn't have to, I can't tell whether there is also Ammonium Ferric EDTA in BLIX part A of this product. Is it a very thick red liquid? What does the BLIX look like?

The unmixed part was almost black. The kit uses 200ml A + B to make the liter of blix. It looks.............like blix. Perhaps darker than the Unicolor, but w/o side by side, that's subjective. The one bottle I don't need to label!

 

[Rudeofus]

Thanks for the update. It certainly appears that Rollei/Calbe created a mix of Ammonium Ferric EDTA and Ammonium Ferric PDTA to get a stronger bleach. Ammonium Ferric EDTA is a food supplement and therefore left out of the MSDS, that's at least my interpretation of what I see here. It's not new, that multiple iron chelating agents are used together in bleaches to reach certain desired properties, but so far I have not seen this in BLIXes, and I most definitely was not aware, that Ammonium Ferric PDTA can be in a stable BLIX in more than trivial amounts.

 

[Paul Verizzo]

Man, no matter how long one is alive and in this rabbit hole called photography, one still finds things to learn!

Thanks, Rudeofus. Would you say that this is not a good candidate for separating the components? As I've noted earlier, I don't have any technical issue with good blix, but it would be fun to separate. Probably easier to monitor exhaustion. Rollei says chemicals are good for 16 rolls @ 25 or 38 degrees C. Interestingly (???) when processing at 45 degrees, only 8 rolls with one time increase like the other temps, then (*) which says, "The bleach-fixer can be reused twice (I think they mean 1-4 rolls, and 5-8 rolls). For additional processes 50% of the (blix) has to be exchanged with fresh solution."

Why might that be?

An aside, I did two rolls @ 77 degrees, oops, 25 degrees and they came out fine. At least by scanning and viewing standards. But 13 minutes? Oy vey. Using graph paper, I came up with 5 minutes @ 94/34, and 7 minutes @ 86/30. The three factory temps and times appear lineal.

I've seen MSDS's that I am sure an extra ingredient was thrown in. Perhaps so a new one didn't have to be created with a minor change of ingredients? To throw off copy cats? Why not, no one is checking.

 

[Rudeofus]

All BLIX kits I have seen so far have used Ammonium Ferric EDTA as their sole bleaching agent. Since this is a very mild bleaching agent, good BLIX kits include a bleach accelerator compound such as Mercaptotriazole. This bleach accelerator is essential for the bleach, too, in case you convert a BLIX kit to separate bleach&fix. I know from personal tests preceding this article, that a bleach mixed from Ammonium Ferric EDTA and Ammonium Bromide alone plus pH adjustment gives brown slides.

Rollei possibly added a more powerful bleach agent to avoid the need for a bleach accelerator. I have no personal experience whether this also works with my procedure, but chances are it does. I do know that Ammonium Ferric PDTA plus Ammonium Bromide produces a working bleach which does not require a bleach accelerator.

You could give it a try with a small sample and a test clip and post the results here.

 

[Rudeofus]

For additional processes 50% of the (blix) has to be exchanged with fresh solution."

Why might that be?

A bleach uses some of its bromide and its acidity, but its oxidative strength is restored with aeration. A BLIX, however, gets loaded with silver over time, and if its fixer component gets clogged with silver, then both bleaching and fixation will be incomplete. Therefore a BLIX can be reused much less than a bleach. It should not come as a surprise, that Tetenal sells BLIX kits to amateurs and bleach&fixer kits to labs.

 

[Paul Verizzo]

A bleach uses some of its bromide and its acidity, but its oxidative strength is restored with aeration. A BLIX, however, gets loaded with silver over time, and if its fixer component gets clogged with silver, then both bleaching and fixation will be incomplete. Therefore a BLIX can be reused much less than a bleach. It should not come as a surprise, that Tetenal sells BLIX kits to amateurs and bleach&fixer kits to labs.

Yeah, but why 50% blix life when processed at the higher temperature? At that weird temp the Blix time only goes down 1 minute, anyway.

 

[Paul Verizzo]

I don't have Ammonium Bromide, and I'm not inclined to buy it for a "maybe." What about Potassium Bromide? I have an amount of that.