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  1. #21
    MattKing's Avatar
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    Quote Originally Posted by Murray Kelly View Post
    Dorff, a link please. Can't find it. TIA

    look up my thread with the attached excel calculation sheet

    Murray
    I'll fill in for Dorff: http://www.apug.org/forums/forum37/1...alculator.html (I expect)

    Just click on his name, go to his profile and click on the link for his most recent started threads.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  2. #22

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    parodinal is interesting other thing, but this thread related to EZ-Rodinal and my question in post #18 about differences between two version of EZR is still open.

  3. #23
    Ian Grant's Avatar
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    Rodinal cannot be made from p-amino phenol hydrochloride, it has to be the free base. This can be made first from the hydrochloride. So the formula you quote is wrong.

    Ian

    Quote Originally Posted by Relayer View Post
    Hello

    I was found two different formula for EZ-Rodinal

    1st early version found here: http://www.apug.org/forums/forum37/2...titutes-4.html

    Start with 700 ml water at room temperature.
    Add 170 grams of anhydrous sodium sulfite, 14 grams sodium hydroxide, and stir till dissolved. Warming it a little won't hurt. Add 40 grams p-aminophenol (not the hydrochloride). It will not all dissolve. Add water to make 1 liter. When you transfer from the mixing vesel to storage, do not filter out the sediment. Use it like AGFA Rodinal.

    2nd (latest) version from EZ-Rodinal article http://www.apug.org/forums/forum223/...z-rodinal.html

    To 400 ml water, add:
    85 g anhydrous sodium sulfite.
    40 g p-aminophenol base.
    Stir well. Add
    13.8 g sodium hydroxide or 19.2 g potassium hydroxide.
    Add water to make 500 ml.

    rewrite this formulas for 1l concentrate:

    1st version
    Sodium sulfite 170g
    p-Aminophenol base 40g
    Sodium hydroxide 14g
    Water 1l

    2nd version
    Sodium sulfite 170g
    p-Aminophenol base 80g
    Sodium hydroxide 27.6g
    Water 1l

    easy to see that 2nd version have twice amount of p-Aminophenol. Compared to known Rodinal formula from http://www.digitaltruth.com/data/rodinal.php

    p-Aminophenol Hydrochloride 50 g
    Potassium Metabisulfite 150 g
    Sodium Hydroxide 100 g
    Cold water to make 1L

    while we mix all ingredient reaction describes next formulas

    K2S2O5 + 2NaOH = K2SO3 + Na2SO3 + H2O
    C6H4OHNH2.HCl + 2NaOH = C6H4ONaNH2 + NaCl + 2H2O

    MW(C6H4OHNH2.HCl)=145.59, so formula contains 50/145.59=0.343M of p-Aminophenol Hydrochloride. For PAP base MW(C6H4OHNH2)=109.13. and amount of base will be 109.13*0.343M=37.48g. This is near the 50g in 1st version of EZ-Rodinal.
    Amount of K2SO3+Na2SO3 is 1.35M. We need 1.35M*MW(Na2SO3)=1.35M*126.04=170g of Sodium sulfite. This is also same as in 1st version.

    So my question - is the 2nd version of EZ-Rodinal correct?

  4. #24

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    Quote Originally Posted by Ian Grant View Post
    Rodinal cannot be made from p-amino phenol hydrochloride, it has to be the free base. This can be made first from the hydrochloride. So the formula you quote is wrong.
    Ian, check again ))

    C6H4OHNH2.HCl + NaOH = C6H4OHNH2 + NaCl + H2O
    C6H4OHNH2 + NaOH = C6H4ONaNH2 + H2O

    so my formula is correct

    C6H4OHNH2.HCl + 2NaOH = C6H4ONaNH2 + NaCl + 2H2O

  5. #25
    Ian Grant's Avatar
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    Quote Originally Posted by Relayer View Post
    Ian, check again ))

    C6H4OHNH2.HCl + NaOH = C6H4OHNH2 + NaCl + H2O
    C6H4OHNH2 + NaOH = C6H4ONaNH2 + H2O

    so my formula is correct

    C6H4OHNH2.HCl + 2NaOH = C6H4ONaNH2 + NaCl + 2H2O

    I repeat Rodinal does not contain p-aminophenol hydrochloride, so that's not the correct formula, it has no chloride of any form.

    If you start with the Hydrochloride first you precipitate and collect the free base. There's many descriptions on how to do this in books.

    Ian

  6. #26

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    Quote Originally Posted by Ian Grant View Post
    I repeat Rodinal does not contain p-aminophenol hydrochloride, so that's not the correct formula, it has no chloride of any form.
    Rodinal contain only PAP.Na salt Sodium Aminophenolate with formula C6H4ONaNH2. But isn't important how we obtain it. From base or from HCl or H2SO4 salt.
    About NaCl. You can easy check that total amount of NaCl will be near 20g/l. When dilute rodinal 1:50 we have 20/50=0.4g/l NaCl in working solution. You sure that such amount of NaCl change property of developer?
    Last edited by Relayer; 05-04-2013 at 08:36 AM. Click to view previous post history.

  7. #27
    Ian Grant's Avatar
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    Yes the presence of Chloride alters the developer slightly. Enough for Andressen to use the free base in Rodinal.

    Ian

  8. #28

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    This may be off topic but Mr Gainer experimented with adding table salt to Rodinal. I lack interest in mixing home brews but adding a little salt is simple if it produces a repeatable result to achieve a desired negative property. Hopefully Pat will add what he knows about salting Rodinal.
    Last edited by Richard Jepsen; 05-04-2013 at 11:00 AM. Click to view previous post history.
    RJ

  9. #29

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    Quote Originally Posted by Ian Grant View Post
    Yes the presence of Chloride alters the developer slightly. Enough for Andressen to use the free base in Rodinal.
    less than 1g/l of NaCl isn't important, be sure. all my post and formulas is correct. but question is other - why we have two different formulas of EZ-Rodinal

  10. #30
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    Quote Originally Posted by Relayer View Post
    less than 1g/l of NaCl isn't important, be sure. all my post and formulas is correct. but question is other - why we have two different formulas of EZ-Rodinal

    Andresen felt differently which is why Rodinal has no Chloride, it's enough to have a slight effect as these are equilibrium equations.

    Agfa and Andressen make a point of stating Rodinal contains only the free base in his publications so any formula based on the hydrochloride is not the same as Rodinal.

    Ian

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