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  1. #1
    htmlguru4242's Avatar
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    Coffee Developers - Why do they Work?

    I've notices that the various coffee-based developers (specifically "Caffenol LC+C" - [Kudos to Donald Qualls for that one], seem to work very well, especially considering that they're made from coffee and washing soda.

    So, I've been wondering: what is it in the developer that acutally causes it to work? I know that coffee contains, tannins, phenols, a host of acids, and lots of other chemical goodies.

    Can anyone give any chemical insight into this?

  2. #2
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    Tannins and the vitamin C in many of these work. Red wine works for the same reason - tannins. Acorns, boiled in water work if you use the liquid due to the tannins. Read about it in Haist.

    PE

  3. #3
    htmlguru4242's Avatar
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    Red wine as a developer?

    This I must try ... and it has to smell better than the coffee concoctions :-P

  4. #4
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    If you drink enough of the red wine, you won't smell the coffee developer.
    Gadget Gainer

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    Quote Originally Posted by gainer View Post
    If you drink enough of the red wine, you won't smell the coffee developer.
    LOL !!
    silver magnets, trickle tanks sold
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    PM me for details

  6. #6

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    Coffee contains several chemicals that are derivatives of catechol. This may account for its developing properties. I think that most people consider ability this to be a curiousity more than anything else.

  7. #7
    Ole
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    Tannic acid was one of the first developers for silver halide emulsions.

    What happens is that developers contain a weak reducing agent which changes the (exposed) silver halides to metallic silver. There are a lot of chemicals that work; but many of them work a little too well and will reduce the unexposed halides as well.

    Some of the stuff in coffee just happens to have reduction potentials inside the useful window.
    -- Ole Tjugen, Luddite Elitist
    Norway

  8. #8

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    Quote Originally Posted by Ole View Post
    Tannic acid was one of the first developers for silver halide emulsions.
    I think you mean gallic acid, which is a building block of hydrolyzable tannin.

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    Ole
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    Quote Originally Posted by Ryuji View Post
    I think you mean gallic acid, which is a building block of hydrolyzable tannin.
    Oops - you're right. An internal translation error, I believe (German -> Norwegian -> English, without involvement of a brain).
    -- Ole Tjugen, Luddite Elitist
    Norway

  10. #10

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    My understanding is that the primary "developing agent" in coffee is in fact caffeic acid, which is a glycoside of 3,4-dihydroxycinnamic acid (a catechol derivative, as Gerald mentioned). Caffeic acid is structurally unrelated to caffeine.

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