Cibachrome Bleach recipe

Hi all,

I found out recently that I can't get p30 chemistry anymore, so I'd like to try to make a cibachrome bleach myself. Is that possible? Many thanks

No. There are no recipes for bleach, and even if there were the components would probably be as hard or harder to get than P30. Why cant you get P30?



Wayne

A lot of camera stores find that they cannot turn-over their merchandise fast enough for lesser-used items, and elect to just tell their customers that they cannot get the item anymore, when in reality that is not truly the case. Do you have evidence from the manufacturer that the P30 processing kit is not available in your country?

The new kit is called P 3.5, and it should be available - just bought a new teo weeks ago.

Ansgar

Alien is right of course, P30 just has a new name now and it comes in larger (more expensive) quantities.


Wayne

There are bleach formulas and I have mixed it from scratch. It is rather simple, but you need several rather nasty ingredients. Among them are phenazine or something similar (I'll look up my list and post it if anyone is interested - for the most part these are carcinogens), and sulfamic acid or concentrated sulfuric acid.

That is basically it. Two ingredients plus some odds and ends IIRC. Not hard at all. Quite doable if you take proper precautions.

PE

Hi PE,

that would be great, I have a fume hood available and working with carcinogens is not new for me. Many thanks.

I would like to see the recipe too, though probably I wont be mixing any soon.



Wayne

I'll look it up today. It is buried in a folder called Dye Bleach somewhere or other.

PE

After a long search, the patent appears to be missing from the folder. Isn't that always the case?

Anyhow, I found a generic dye bleach without all of the variations in another patent. Here it is.

quinoline 50 ml
Sodium hypophosphite 5 g
Potassium Iodide 10 g
Sulfuric acid conc. 75 ml

Water to 1 liter.

I have seen phenazine and phenazine derivatives used in this type of bath at from 10 - 100 mg / liter instead of quinoline. The other patent gives the list and concentration ranges. I always used phenazine.

I have also seen the catalyst added to the developer to promote uniformity in bleaching.

You can test the bath by mixing it, then fogging a small piece of dye bleach paper and developing it, then bleaching it in the bleach bath above. It should bleach uniformly down to a whitish dmin. After washing, fixing and washing it should be a good white with no color cast. If the cast is cyan, then the bleach did not reach the bottom layer and is diffusing too slowly or is not present in high enough concentration and must be adjusted.

If it gives other color casts, there are real problems. Adding the catalyst to the developer can help in some cases. If that does not fix the problem, then you are using the wrong catalyst.

I'll keep looking for a better formula.

PE

I finally found it.

Ok, first some history. At one time, Kodak was in the final stages of development of a new product to be called Azochrome. It was based on dye bleach technology. Its introduction date was to be Monday, December 8th and turned out to be the day after Pearl Harbor. The introduction was cancelled, for obvious reasons and no one ever heard of the proposed product and it was never introduced.

However, there were several patents granted, and this is one of them that resulted from that work. It is USP 2,322,084. It contains 15 examples of a dye bleach BLIX, something that was to be used in this process but never was realized. If you leave out the fixing agents, they work as dye bleach solutions.

The patent does describe the various catalysts that can be used though and the acids. I prefer sulfuric acid, thereby eliminating the odor of hydrochloric acid.

As I said before, I mixed mine with sulfuric acid, phenazine and KI.

The patent also describes the dyes used and how they were made.

PE

Ciba bleach recipe

Narigas 2006,
i was wondering why you cant get ciba chems any more.
If your having a problem call Illford its their product..
John

Well dont look too hard on my account PE, since I havent done cibas in several years, but this is great to know. I am sure I'll try it again someday and I'll be curious to know if someone else tries a homebrew bleach. That may be the only option left when I come back to it again.


Wayne

John Meyer said:

Narigas 2006,
i was wondering why you cant get ciba chems any more.
If your having a problem call Illford its their product..
John

Click to expand...

Hi John,
I did call them but they sell p3 chems in huge amounts and I just have a few sheets. Also, PE, just a quick question, quinoline, does it dissolve in water? Also, can I use d76 as a developer? Many thanks. richard

Quinoline is not my preferred catalyst and it does not dissolve in water to any great degree, just slightly. However, it dissolves in acid.

I cannot guarantee that these bleaches and blixes will work though. Run that test first to see if it even has a hint of working.

PE

narigas2006 said:

Hi John,
I did call them but they sell p3 chems in huge amounts and I just have a few sheets. Also, PE, just a quick question, quinoline, does it dissolve in water? Also, can I use d76 as a developer? Many thanks. richard

Click to expand...

You want P3.5 not P3. It comes in 5-liter kits, which may still be more than you want. If you only have a few sheets it isnt going to be cost effective anyway and you're probbaly better off having someone do it for you.

I'm wary of the bleach recipe, since its apparently not been tried. FYI if it helps, P30/P3.5 bleach contains

PartA
p-toluene sulfonic acid
a quinoxaline adduct (CAS confidential) and
sodium m-nitrobenzenesulfonate

Part B
Potassium carbonate
potassium iodide
trialkylphosphine sulfonate (CAS confidential)

Part C
sulfamic acid

You probably know that you need to add hypo to a homebrew developer. IIRC its about 1/4 teaspoon per liter (the amount isnt critical) but I can look it up. Any standard B&W print developer should work. I dont know about D76.

But this seems an awful lot of trouble to go to when P3.5 is available.

Wayne;

I agree. Although I have mixed my own, I really don't recommend it.

PE

This is my first APUG post and I'm going to jump in with two feet and speak from a ten year old memory - though I should be able to recover more information from my notes of the time if there is any interest.

Can it be done ? Yes

Is it hazardous ? Not especially. Sulphamic acid is a solid. You do need a potentially carcinogenic compound [the phenylenediamine derivative] but its pelleted and you just don't handle it or breathe the dust [similar compounds are still used in hair colours so they can't be that extreme]

Is it worth doing ? No. Too expensive. Much too much trouble. Use Ilford's product.

Formulae which work are published in Ilford's patents. Some of the ingredients came from the late Albert Raymond who trades as AR photo chemicals and some of the others were ordered by Mr. Raymond for me from Aldrich.

The essential component is the bleach-fix catalyst, 2,3,6-trimethyl quinoxaline which is not a common commercial chemical [Aldrich did not stock it] and the only suppliers who did wanted completely inaccessible prices. So I made it from the para-phenylendiamine precursor and diacetyl. The difficulty was purifying the black oil/paste by re-crystallisation until it was light enough not to risk staining the prints.

Although Ilford's MSD sheets did give the CAS number for the trialkyl phosphine sulphonate and its preparation was described in the original patents, I never discovered enough about the compound or its precusrors to say whather itwas possible to get some or prepare it: I suspect not.

The compound is an accelerator: Without it the bleach acts much more slowly. However, other Ilford patents did provide alternative accelerators which were accessible and did produce the right speed - BUT which would need to have been packed seperately in a commercial product.

The final step was the trickiest, adjusting the quantity of sodium nitobenzene sulphonate in order to get the right contrast and hues.

You will see what I mean about a heap of trouble !

The synthesis would have to start with 4 methyl ortho phenylene diamine to give the referenced 2,3,6 - trimetyl quinoxaline from diacetyl. The p-phenylene diamine places the nitrogens too far apart to react properly and gives a polymer.

But yes, it is a problem. I discussed this with the head of Ciba research back in the 70s, just before he retired. We eventually used another accelerator for this which is proprietary and was never patented. It is a very common chemical and would only work under our conditions.

Phenazine worked well for my coatings however. Have you ever tried it?

PE

Grweenfields said:

You will see what I mean about a heap of trouble !

Click to expand...

Oh yeah. Long live Ilford!


Wayne

PE is right - it was the ortho-phenylenediamine. Its oxidation products are so strongly coloured and difficult to remove [by zone refining] that only the technical grade was affordable. It was dark chocolate brown, and so initially were the quinoxalines.

The accelerator contained benzotriazole - and, I think from memory Dimezone-S, which appeared to keep almost indefinitely together as a concentrated stock solution in isopropanol. That did achieve the speed of the official bleach.

I tried 2-3 dimethylquinoxaline as well because that appears in most of Ilford's patents before they disclosed use 2,3,6-trimethylquinoxaline in their MSD sheets. That is a bit easier to prepare and "clean up" by recrystallisation from an isopropanol/water mixed solvent. It crystallises as hollow needles with dirty solvent inside the hollows but one recrystallisation produce produced a yellow product which worked and did not stain the prints.

2,3,6-trimethylquinoxaline preciptates from a diacetyl mixture with the ortho-phenylenediamine. If the diacetyl was used as a bisulphite addition [by mixing it with the right amount of a metabisulphite solution first] there seems to be less loss when the condensation reaction heated up. The trimethy derivative is more difficult to recrystallise. If you get the proportions of isopropanol and water wrong you either get no crystals or a fibrous mass from which its difficult to express the solvent. I think that the fibrous crystals were only a frew micons in diamater and that they were also hollow - but it was hard to be sure that I was not simply observing diffraction effects in an optical microscope.

The diacetyl smell [Diacetyl is the compound which in traces gives butter its smell] stank out the neighbours !

The alternative solutions worked - but I had no colour sensitmetric equipment to compare them with the official results: only judgement which is notoriously fallible. I'm also sure that Ilford's versions would be better commercial products - in terms of sensitometry and keeping qualities both in use and in storage.

Why bother ? I suppose it was the photochemical equivalent of hacking without the malice. Great fun at the time.

GRW;

You would never imagine the fun of actually coating the stuff. I have duplicated Cibachrome material in the lab at Kodak, and believe that if an individual is to make a color material, dye bleach is the only chemistry within reach for hobbyists.

A coating of dye bleach materials is so trivial it is a no-brainer. I could take any of the paper emulsions I have and blend them with an azo dye and have a single color coating. I could not do it using coupling chemistry.

Dimezone-S, under the right conditions, can act as a catalyst itself or under other conditions as an electron transfer agent for the true catalyst. As I said, I used phenazine.

I never minded the smell of Diacetyl. It was rather pleasant to me, just like cinnamaldehyde. I did a lot of research on the reactions of Diacetyl with amines when I was in graduate school. Phenyl acetic acid now is another story, as well as pivalic acid. They remind me of the monkey house at a zoo, and cadaverine and putrascene as well as scatol, well, the names speak for themselves. Then there is always t-butyl mercaptan, the essence of oil of skunk. So, there are a lot worse smells than diacetyl.

PE

D.William Reichner tried his hand at making a Cibachrome bleach back in 1976. The formulas were published in the Dignan Photographic Newsleter Volume 4, Numebers 1 and 2. Those who tried it generally reported terrible results, probably because of the bleach catalyst he used, but it did sort of work. Just for information, here it is:

Distilled water (27C) 800 ml
Sodium bisulfate 14.5 g (Note: bisulfate, not bisulfite)
Sodium chloride 6 g (Iodized table salt was recommended)
Ascorbic acid 500 mg
Potassium iodide 16.5 g
Catalyst solution 9 ml
Distilled water to make 1 l

The catalyst solution was made by dissolving 1.0 g of 2,3-dimethylquinoxaline in 100 ml of 70 percent isopropanol (rubbing alcohol) and then adding 100 ml of distilled water.

The dye destruction bleach was followed by a most unusual blix:

Distilled qater (27C) 800 ml
EDTA Ferric 60 g
Ammonium thiocyanate 10 g
Sodiun sulfite (anh) 3 g
Ammonium thiosulfate (60%) 200 ml
Distilled water to make 1 l

When dye bleach works properly, no silver should be left behind to require a blix. The silver will completely remove dye by bleaching it, and the dye will totally remove the silver leaving Dmin in whites. The dye bleach solution should be followed by only a fix to remove remaining silver halide. I believe that this formula is not acidic enough.

If a blix is needed, then the dye bleach is severly anemic.

The blix above is perfectly normal for chromogenic color materials.

That blix will work quite well with color papers, and follows one of my published (patented) formulas quite closely IIRC, but it can leave iron stains in prints. It needs extra EDTA to prevent that, and there is none. It also would require a pH adjust.

PE