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  1. #1
    hka
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    Problems with mixing D-76H

    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 ingrediŽnt 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.
    harry

    Release, the best you can do...

  2. #2

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

  3. #3
    hka
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    This is the Grant Haist formulary without the HQ.
    harry

    Release, the best you can do...

  4. #4

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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. #5
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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.
    Michael Sebastian
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  6. #6
    hka
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    Quote Originally Posted by MikeSeb View Post
    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.
    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.
    harry

    Release, the best you can do...

  7. #7

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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...

    Quote Originally Posted by hka View Post
    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.

  8. #8

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    Quote Originally Posted by hka View Post
    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 ingrediŽnt 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.
    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.
    Tom Hoskinson
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    Everything is analog - even digital :D

  9. #9

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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 And if there was a sodium sulphide, or thiosulphate...

    Quote Originally Posted by Tom Hoskinson View Post
    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.

  10. #10

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    Quote Originally Posted by eumenius View Post
    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 And if there was a sodium sulphide, or thiosulphate...
    Thank you for your correction and clarifications, eumenius!
    Tom Hoskinson
    ______________________________

    Everything is analog - even digital :D

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