Problems with mixing D-76H

Discussion in 'B&W: Film, Paper, Chemistry' started by hka, Oct 6, 2007.

  1. hka

    hka Member

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    Yesterday evening I mixed from scratch a new badges D-76H developer.
    Not ever mixed before this type. It seems a piece of cake to me because I mix my own Pyrocat HD from scrtach to. Never sorted any problem.
    I weight carefully the ingrediƫnt and mixed them in water. This afternoon I made a test with a piece of film to check if the developer is active. There was no reaction even the film markings of the manufacturer didn't appear. So I was wondering where this problems come from.
    The ingredients I used are:
    Metol, 2g - M=334,39 g/mol - CAS 55-55-0
    Natriumsulfiet, 100g - M=126,04g/mol - CAS 7757-83-7
    Borax 2g - M=201,22 g/mol - CAS 1330-43-4
    These data where found on the labels of the chems.
    We do have here one of the best waterqualities in the world and have never experienced any problem with it.
    I'am not a chemist realy, I only follow the descriptions as mentioned in de the Film Developing - and Darkroom Cookbook. What did I do wrong?
    Thanks.
     
  2. eumenius

    eumenius Member

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    And what about hydroquinone? Or this developer is of a D23 type, metol only?
     
  3. hka

    hka Member

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    This is the Grant Haist formulary without the HQ.
     
  4. eumenius

    eumenius Member

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    Aha, I see... but it should be less active without a superadditive compound, so the authors have increased metol content. Did all the metol go into solution? As a chemist, I can see only one possible explanation for complete lack of the activity - the metol could have went bad, but it's HIGHLY unlikely, I myself am using a 30+ year old stock of it with perfect results.

    I am really puzzled, to say the least!
     
  5. MikeSeb

    MikeSeb Member

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    I think the formula calls for metol 2.5 g rather than 2.0; but this should not have caused your problem.

    Did you add a pinch of sulfite before adding the metol, then add the rest of the sulfite? If you add more than a "pinch" before the metol, it can cause problems.

    Great developer, cheap, simple.
     
  6. hka

    hka Member

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    I didn't add a pinch of metol before. After inspection of the bottles now I saw some white stuff on the bottoms. Could that be the problem because the amount of metol is very less.
    Yes it is correct I added 2,5g of Metol (sorry mistyped).
    I bought "fresh" metol a half a year ago.
     
  7. eumenius

    eumenius Member

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    While making all metol-containing developers, you have to dissolve first a pinch of required sulfite in a lukewarm water, then dissolve fully the metol required, finally adding the remaining salts and sulfite. If you dissolve the whole sulfite quantity first, the metol becomes not readily soluble - and if you omit the pinch of sulfite, metol will oxidize quickly. You always have to control the full dissolution of the organic developing substances, and filter the solution before use.

    I guess you have not dissolved your metol...

     
  8. Tom Hoskinson

    Tom Hoskinson Member

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    hka, Is it possible that you received CAS# 7757-82-6 instead of CAS # 7757-83-7.

    If so, you have SULFATE (acidic) in your developer instead of SULFITE (alkaline) in your developer. Needless to say, an acidic solution will not work with Metol.

    If you have litmus paper or a pH meter you can easily test this possibility.
     
  9. eumenius

    eumenius Member

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    Tom,

    sodium sulphate solution would have the pH close to neutral - this salt is formed by a strong acid and strong base, so no hydrolysis would occur upon electrolytic dissociation of it.

    Sulphite in that recipe is the only source of mild alkali, so if sodium sulphate is used instead of sulfite, the reason of non-working developer is found :smile: And if there was a sodium sulphide, or thiosulphate... :smile:

     
  10. Tom Hoskinson

    Tom Hoskinson Member

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    Thank you for your correction and clarifications, eumenius!
     
  11. gainer

    gainer Subscriber

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    The purpose of the sulfite in this developer can better be served by the ascorbate. I think you will be satisfied if you use 8.8 (0.05 M) grams of ascorbic acid in place of the sulfite and increase the borax to 100 grams. You may also use sodium or potassium ascorbate at 0.05 M. Whether you believe me well enough to try it is up to you. I think you will be surprised at the result if you do.
     
  12. hka

    hka Member

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    Tom,
    I checked the label and CAS # 7757-83-7 on it. That must be oke then.
    Maybe the lack of a pinch Sulfite before adding the Metol in the water is here the problem?
    I'am busy at the moment to make a new badge and come back later with the results.
    Thank you all for your time answering this question.
     
  13. hka

    hka Member

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    Gainer,
    First of all I have the solve my problem at this stage. Later on I will give this opportunity a chance. Thanks anyway.
     
  14. hka

    hka Member

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    As said I made a new badge D-76H and have done first a test with a piece of film to see if there is any activity...
    ...And, YES there is.
    Souped just a film in this new badge and the negatives came out very nice in tonality.
    Perhaps the pinch of sulfite may caused this problem. I used the same chems as yesterday. I patiently waited until each chemical where dissolved before adding the next one.
    Problem solved. Thanks.
     
  15. gainer

    gainer Subscriber

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    I thought I posted this last night. I'm glad it tidin't go through. I had a big boo boo.

    The sulfite in D-76H, besides serving as the alkali, is to keep oxidized Metol from slowing sown the reaction. Sodium or potassium ascorbate is more effective because it regenerates the oxidized Metol. If you substitute 8.8 grams of ascorbic acid or 10 grams of sodium ascorbate for the sodium sulfite and increase the borax to 25 grams, you may be quite happy with the results. You will wind up with 2.5 grams of Metol, 8.8 grams of ascorbic acid (0.05 M) and 25 grams of borax to make a liter of working solution.
     
  16. gainer

    gainer Subscriber

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    Well, it did go through. You now can see that the boo-boo was in the amount of borax, which was 4 times too large for a liter. I think my machine is acting up. I would hate to think my brain was beginning to fail after only 80 years.
     
  17. jbj

    jbj Member

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    the ratio of metol/Na Sulfite/borax seem appropriate for D76H based on my experience.

    I noticed that you listed the mw of your sulfite as the anhydrous. Over time due to its hygroscopic nature it will pick up water to form hydrates and you'll have to compensate by adding water to the mw/mol.

    i think monohydrate and heptahydrate are common stable hydrates of Na2SO3

    how does the sulfite look? free flowing granules, crystals, clumps?

    If hydrates are forming you'll have to increase the amount of Na2SO3 to compensate.
     
  18. dancqu

    dancqu Member

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    That may be the case for no more than sulfite
    or lower ph activated developers. Sulfite though
    will regenerate metol in carbonated developers. So
    use an ascorbate and activate with borax. Why not
    not go all the way and scrap the metol for phenidone?
    D-76-PAB? Dan
     
  19. gainer

    gainer Subscriber

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    Where did you get that information about regeneration in carbonated developers?

    Anyway, the article on experiments with Metol and ascorbic acid goes on to describe other combinations including phenidone with ascorbic acid and borax. I have noticed very little difference in performance other than developing time. I'm not sure, if I shuffled strips of negatives from each combination, that I could tell which was which as long as CI was the same. In other words, whatever agent you have on hand will do about the same job where grain, resolution and gradations are concerned when you mix it with 0.05 M ascorbic acid and borax at or near saturation. You could start with 0.01 M concentration of the agent. That's about all you can dissolve of phenidone anyway. Metol is a little different in that 2 molecules of its base are combined with 1 molecule of sulfuric acid to form 1 molecule of Metol, so 1 molecule of Metol is worth 2 molecules of phenidone or p-aminophenol.

    I purposely stayed away from stronger alkali so as not to activate ascorbic acid and to get the buffering of the thick borax solution. A highly buffered self replenishing developing solution will have a high capacity. An advantage of phenidone may be its low sensitivity to bromide concentration. I haven't done all possible comparisons. I have in mind immersing a test strip in one of these developers, wiping off the excess, and hanging it in the dark to see if the amount of developer absorbed by the emulsion will be sufficient to develop it fully. Sort of a 2-bath without the second bath.

    You may argue on the besis of current thinking that this highly buffered developer will not produce very sharp negatives, but a test is worth a thousand arguments.
     
  20. Anscojohn

    Anscojohn Subscriber

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    No. The borax is also an alkali. There should be plenty of alkali with 100 grams sodium sulfite and 2 gms borax. But, as stated, if sodium sufAte were used, it would reduce alkalinity to below threshold needed for metol to work.

    John, Mount Vernon, Virginia USA
     
  21. hka

    hka Member

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    Mr. Gainer
    What about the self-life with the use of ascorbic acid. Will it be as steady als de "original" recipe?
     
  22. gainer

    gainer Subscriber

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    The ascorbic acid is certainly oxidized by the oxygen dissolved in the water of solution, but this is mostly over with soon after mixing. It is too soon to make a guess about years, but after months of storage I see no difference. The ascorbate formed on mixture is in excess of the minimum required by a factor of about 2. Its function is not to serve as a developing agent, but to regenerate the Metol. Metol is not extremely sensitive to bromide concentration. I cannot see how the Metol-C-Borax solution could have any shorter shelf life than the D-76H.
     
  23. dancqu

    dancqu Member

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    I've just brought forward the thread "An Interesting Aspect ... "
    Alan Johnson's posts detail some of G. W. Crawley's work with
    non-regenerative low sulfite carbonated developers. Dan