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  1. #1

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    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

  2. #2

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    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

  3. #3

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    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?

  4. #4
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    The new kit is called P 3.5, and it should be available - just bought a new teo weeks ago.

    Ansgar

  5. #5

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


    Wayne

  6. #6
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    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

  7. #7

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    Hi PE,

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

  8. #8

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



    Wayne

  9. #9
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    I'll look it up today. It is buried in a folder called Dye Bleach somewhere or other.

    PE

  10. #10
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    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

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