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  1. #11
    pierods's Avatar
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    Quote Originally Posted by Athiril View Post
    I just finished some tests with Kodak D-76 vs the D-76 standard formula:

    Stock vs Stock.

    Kodak D-76 is slightly sharper and grainier, otherwise identical results. Test was on T-Max 100.

    details: http://www.photodan.com.au/2013/04/k...6-differences/


    Kodak D-76: http://www.photodan.com.au/wp-conten...013/04/D76.jpg
    D-76 Standard Recipe: http://www.photodan.com.au/wp-conten...13/04/PC11.jpg
    Wow!

    Everybody said it's the opposite - less SS, more grain, sharper...

  2. #12
    Ian Grant's Avatar
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    What are you saying is Kodak D76 and what is D76 standard recipe ?

    Commercial D76 is somewhere between D76 and D76d with some Boric acid alongside the Borax, but with greater buffering than the original published D76 formula. I guess that's what you're saying. The buffering is also slightly higher with commercial ID-11.

    D76 wasn't designed for dilution but that's become a common practice since WWII days, so maybe the increased buffering is designed to help with stability of pH when diluted.

    Ian

  3. #13
    Ian Grant's Avatar
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    Quote Originally Posted by pierods View Post
    Wow!

    Everybody said it's the opposite - less SS, more grain, sharper...
    That's not what he's said, he's not compared D76 with less Sulphiter, rather the commercial to the published formula.

    If you reduced the sulphite you'd probably change the M-Q balance as well to achieve optimal results. Look at Abox Borax MQ, which is EFKE FR2

    Ian

  4. #14
    Athiril's Avatar
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    Quote Originally Posted by Ian Grant View Post
    What are you saying is Kodak D76 and what is D76 standard recipe ?

    Commercial D76 is somewhere between D76 and D76d with some Boric acid alongside the Borax, but with greater buffering than the original published D76 formula. I guess that's what you're saying. The buffering is also slightly higher with commercial ID-11.

    D76 wasn't designed for dilution but that's become a common practice since WWII days, so maybe the increased buffering is designed to help with stability of pH when diluted.

    Ian
    The standard recipe. You know. Not derivatives, modifications. Not D-76b/c/d/x/etc, just D-76. Which is listed on the first link I provided :P

    Metol 2g/L
    Sodium Sulphite 100g/L
    Sodium Tetraborate (Borax) 2g/L
    Hydroquinone 5/gL

    Kodak D-76 is still 109g/L the same as the above recipe, so in order to include other ingredients, or increase one, something has to be reduced (ie: probably the Sulfite).

    If it is otherwise D-76d.. 2g/L Metol, 5/gL HQ, and 8g/L Borax and 8g/L Boric Acid, logically Sodium Sulphite is 86g/L not 100g/L.

    Of course the commercial stuff would also have a chelating agent.. in this case pentetic acid. The MSDS lists Boric Anhydride as the other chemical used, which is dehydrated Boric Acid.

    So it should go B2O3 + 3H2O -> 2H3BO3

    69.6182g + 3x~18.01528g -> 2x61.83g

    Essentially, 1g of Boric Anhydride giving 1.78g of Boric Acid in solution.

    Which goes on to form borates in water with the sulphite, altering the in solution formula.

    Quote Originally Posted by pierods View Post
    Wow!

    Everybody said it's the opposite - less SS, more grain, sharper...

    The standard formula that I used has 100g/L Sodium Sulphite. I am certain Kodak D-76 has less than that when mixed up in solution.

    Logically I highly doubt that Kodak D-76 ends up with less than 75-80g/L of Sodium Sulphite in solution. So I disagree with the fact that amounts above 75-80g/L do not provide any more effect. I am experiencing a very noticeable effect. If theory doesn't match observation, there is something wrong with it.

    Given that, and if people are reporting 75g/L D-76 recipe as sharper/grainier than Kodak D-76, logically it's somewhere between the 75g/L and 100g/L value.

    Split the difference and it's 87g/L.


    If there is 2g/L of Boric Anhydride in Kodak D-76 bag (it still has to add up to 109g/L), that puts Sodium Sulfite at 100g/L in the bag, but in solution, if my calculation is right, that would drop sodium sulfite to 89g/L, and 5.47g/L of Borax Decahydrate equivalency (I think, if my calculation is right).
    Last edited by Athiril; 04-11-2013 at 08:50 PM. Click to view previous post history.

  5. #15
    martellsv's Avatar
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    100g/l Sodium Sulphite ?

    Kodak D-76 is still 109g/L the same as the above recipe, so in order to include other ingredients, or increase one, something has to be reduced (ie: probably the Sulfite).
    I have a Kodak D-76 package also has the wt % of borax penta, ( and looking and some olds MSDS...), IMHO there is no 100 gr/l, i donīt know exactly if 9o g/l or similar?... and a difference of three grs. i think won't be important, Again the difference in ph of several grs of sodium sulphite is not noticiable. i dont know if the other component is oxide boron or acid boric... but i am not sure this is relevant, to reach 109 g/l additives must be added.
    Ph cuestion, i have reach ph 9,0 with my scientific phmeter in D-76, at list in this developer homemade version, and three hours after i get a Ph 8.5. i donīt know is the oxide boron is very acid because the boric acid is slightly acid only -0,3 ph when i mix it after the borax.
    Last edited by martellsv; 08-31-2013 at 09:03 AM. Click to view previous post history.

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