Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,963   Posts: 1,523,264   Online: 1009
      
Results 1 to 6 of 6
  1. #1

    Join Date
    Jan 2005
    Shooter
    Medium Format
    Posts
    397

    HELP LIST OF CHEMICALS FOR DIVIDED DEVELOPER CACHET AB 55

    In my quest to find the formula make up of Cachet AB 55, I found the list of chemicals used in a Precaustions that came with the package. They are as followed along with some notes.

    Sodium Sulfite - common developing agent in developers; can prevent the formation of many undesirable by products during development. Darkroom Cookbook page 195.

    Hydroquinone - builds density in combination with other developers. Darkroom Cookbook Page 182

    1-Phenyl-3-Pyrazolidone - is actually Phenidone. used alone in sulfide solutions, it is very fast but extremely soft working and is only capable of producing negatives of low contrast. In combination with hydroquinone it produces developers with superadditivity that are even more efficient than MQ developers. Phenidone-based developers keeps better than those based on metal. You can read more in Darkroom Cookbook page186. Page 21, 1st paragraph optimum amount of Phenidone to hydroquinone is 7%

    Sodium Tetraborate is Borax. Its a mild accelerator. From what I have read this can be used in Solution B solely. Darkroom Cookbook page 195 but see page 178

    All information comings from the Darkroom Cookbook 3rd Edition.

    As mentioned, I am not a chemist and would like to know where to begin in terms of amount of chemicals to be used in Solution A and Solution B. The only thing I know for sure is that Borax can be used for Solution B only. If anyone can provide a starting point or a solution it would be greatly appreciated.

    Thank you for your time and assistance.


    Edward Vargas


  2. #2

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,769
    The formula for this product is probably a trade secret. As a chemist I can tell you that there is no way that you can determine the exact amounts of the ingredients in this product. You could pay an analytical laboratory to analyse it for you but that would be expensive. You can get a crude estimate of the amount of each chemical by looking at the MSDS for the product.

    If it is any help there are many formulae for two bath developers given on the web. Perhaps one of these would be helpful to you.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  3. #3

    Join Date
    Jan 2005
    Shooter
    Medium Format
    Posts
    397
    Mr. Kock,

    I do thank you for you for your time and assistance.

    According to Mr. Eric Joseph the formula died with with Ike Royer who did the mixing and packaging. I have looked at all kinds of two bath developers and I am seriously looking at these two:

    Barry Thorton

    Solution A Sodium sulfite 80g
    Metol 6.5g

    Solution B 12g Sodium metaborate (Kodalk) Is Kodalk just Borax?

    develop 4-5 minutes at room temperature. Comes close to AB 55



    David Vestal From the Darkroom Cookbook 3rd

    Solution A Metol 3g
    Sodium Sulfite 50g

    Solution B Borax 5g
    Sodium sulfite 50g

    Recommended development times

    Solution A 3 minutes

    Solution B 3 - 5 minutes

    What bothers me is that some two baht developers say, "develop at 68' or 70' and process films at different times for solutions A and B; this gets me confused. Where as I would like to develop at room temperature from 68' to 85' and all films at the same time, something with AB 55 offered.

    So if you can put me in the correct direction if would be appreciated. As mention I am not a chemist.

    Thanks,

    Edward


  4. #4

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,769
    Each of the two developers you mention will behave somewhat like D-23. In fact D-23 can be used as a bath A. Because there will be some development occuring in Bath A these two developers will be temperature sensitive. For the two you mention allowing film to remain longer in bath A will increease density and contrast. Many two bath developers use a bath A that has a sufficiently low pH to prevent development from occuring in it.
    Last edited by Gerald C Koch; 12-14-2011 at 10:30 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #5
    semeuse's Avatar
    Join Date
    Sep 2006
    Location
    Treasure Coast, FL
    Shooter
    Multi Format
    Posts
    462
    Images
    98
    Edward -
    You might try something along these lines:

    part A:
    sodium sulfite - 50g
    hydroquinone - 5g
    phenidone - 0.5g
    water to 1l

    part B:
    borax - 5g
    sodium sulfite - 10g
    water to 1l

    my guess on times would be 3-4 minutes in each part - if you notice streaking in the negatives, you may want to add about 35g of sodium sulfate to part B - and this should also work with the temperature range you specified

  6. #6
    Roger Cole's Avatar
    Join Date
    Jan 2011
    Location
    Suburbs of Atlanta, GA USA
    Shooter
    Multi Format
    Posts
    3,778
    I tried Cachet once, because I like Diafine so much and thought a developer for normal speed with a bit more contrast but the other virtues of a divided developer might be good. I got the normal speed (a bit more than standard actually but not the push of Diafine) and the bit more contrast - the tonality looked fine - but along with it grain like giant golfballs. I've never seen grain like that from 35mm Tri-X before or since. That doesn't seem to have been usual but it was what I found.



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin