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  1. #1

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    Homemade rodinal

    A discussion homemade rodinal based on Tylenol tablets on the flickr forum for alternative developers, Caffenol.
    A look at how developer activity takes time to reach it's full after initial mixing. This is something anyone can do.

    Just go to flickr.com, find discussions.
    Search for discussion no. 72157628011740415

  2. #2
    chioque's Avatar
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    IMHO it's better if you just post the link, much easier for people to follow for those not familiar with flickr.

  3. #3
    Trask's Avatar
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    I agree with chioque -- I had to search around before I discovered that "discussions" could be searched under "search for groups."

    Here's a direct link to the discussion: http://www.flickr.com/groups/3305163...7628011740415/

  4. #4

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    Sorry, just entered and those in power have limiteed whats allowed, links are disallowed, probably a good idea, given todays spam climate......

  5. #5
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    Sooo it's basically Parodinal.

  6. #6
    MattKing's Avatar
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    Quote Originally Posted by analog what is that? View Post
    Sorry, just entered and those in power have limiteed whats allowed, links are disallowed, probably a good idea, given todays spam climate......
    You can actually copy the linking information - you just can't make it an active link.

    Welcome to APUG.
    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

  7. #7

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    Quote Originally Posted by daveandiputra View Post
    Sooo it's basically Parodinal.
    Yes basically, what interested me was if the info "let it stand for 72 hours" really was needed, high hopes and bragging aside, it was!

  8. #8
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    It's Parodinal and the original recipe calls for 72+ hours of waiting time. Activity increases for the whole of the first week, after which it pretty much levels off at the appropriate strength.

    The time taken is for the NaOH to hydrolyse the paracetamol, you definitely have to wait for the reaction.

  9. #9

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    Yes and I just documented what happens during those 72 hours wait, to satisfy my own curiosity.......

  10. #10

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    Another snippet of information:
    The Parodinal formula calls for 20g sodium hydroxide but the chemical equation for the hydrolysis only requires 8g.
    I tried using only 8g sodium hydroxide (along with the sulfite) to hydrolyse the paracetamol/tylenol.
    After 72 hours a 1:50 solution produced very thin negatives and after 10 days still thin negatives.
    So it appears that an excess of sodium hydroxide >8g is needed to complete the reaction in a reasonable time.

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