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  1. #11
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    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

  2. #12

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    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

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    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

  4. #14

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    Quote Originally Posted by John Meyer View Post
    Narigas 2006,
    i was wondering why you cant get ciba chems any more.
    If your having a problem call Illford its their product..
    John
    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

  5. #15
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    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

  6. #16

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    Quote Originally Posted by narigas2006 View Post
    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
    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.
    Last edited by Wayne; 02-10-2007 at 09:52 AM. Click to view previous post history. Reason: to add part B and C

  7. #17
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    Wayne;

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

    PE

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    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 !

  9. #19
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    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

  10. #20

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    Quote Originally Posted by Grweenfields View Post

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

    Oh yeah. Long live Ilford!


    Wayne

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