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  1. #1

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    "Albino" Caffenol failure and questions

    I wanted to try a coffee-free caffenol to reduce a) the smell and b) the cost. The general consensus seems to be that instant coffee contains around 3 % caffeine, so I replaced the 40 g of instant coffee with 1.2 g caffeine, and used the rest of the formula for Caffenol C-H just as is. The film I used was Kentmere 400 (because I wanted to test with an inexpensive film first). I settled on 15 min development because that is typically what I use for Caffenol C-H, and got completely underdeveloped negatives. I would say the N+3 to N+4 looks about normal density. Over and above that, the film was fogged significantly. So I tried increasing the caffeine content to 3 g, and added 1 g KBr to prevent the fogging, keeping the rest the same. This only made things significantly worse, by about another two stops. N+5 looks like something can be rescued from it, but it is still under by a stop at least.

    Okay, so what now? I can only infer that the super-additive component in instant coffee isn't the caffeine, but something else. Or my pure caffeine somehow differs from the form in coffee, but I have never come across any reference to that being a possibility. The ascorbate I use is the same that gives totally acceptable results with instant coffee. Can anyone else make sense of this? I desire a non-staining caffenol-type developer for paper, too, purely for environmental reasons, and was hoping this would work, but it seems it's back to phenidone for now.

  2. #2
    Steve Smith's Avatar
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    It's not the caffeine in coffee which develops film, it's the caffeic acid.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  3. #3

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    Thanks for the clarification, Steve! Oh well, I could make a few energy drinks with my caffeine stash . I'll see if I can find the caffeic acid as a pure compound, then try again.

    BTW, do you know what the typical concentration is in instant coffee?

  4. #4

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    The reason why people use instant coffee is that caffeic acid is not readily available.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #5
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    Gerald, I assume that the phenol group caffeic acid is the main participant in film developer, Caffenol. Do you know if the acrylic group participates or serves any purpose in the reduction of silver halides?

  6. #6
    Steve Smith's Avatar
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    I remember from a previous thread that rosemarinic acid is very similar to caffeic acid so perhaps rosemary oil would work.

    http://en.wikipedia.org/wiki/Rosmarinic_acid

    http://en.wikipedia.org/wiki/Caffeic_acid


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  7. #7
    BradS's Avatar
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    Looks like some derivative of the bark of Eucalyptus globulus might also have some useful photographic properties. Eucalyptus trees are plentiful here in California...and have about the same status as noxious invasive weed.

  8. #8

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    The developer activity is the result of the adjacent hydroxyl groups. Developer activity is determined by the Kendall-Pelz Rule. Substituents on the ring containing the hydroxyl groups can effect the activity of the developing agent. It depends on whether the group adds or removes electron density from the ring.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #9

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    Thanks for all the useful info. I wonder whether caffeic acid is extracted together with caffeine during the decaffeination process, since it seems decaf instant coffee does not develop well. If that is the case, then maybe one can get hold of the fraction after extraction from a coffee factory that does decaffeination. It doesn't need to be purified, just reasonably concentrated. I would guess that supercritical CO2 can be used to extract most of the active chemicals in plants such as rosemary, mint, eucalypt and so on. The question is more whether it is worth the relative effort. I want something that works well enough, and which can be discarded of with negligible environmental issues. But at the low concentrations in which phenidone is active, it remains a reasonable alternative.

  10. #10

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    Quote Originally Posted by dorff View Post
    I want something that works well enough, and which can be discarded of with negligible environmental issues. But at the low concentrations in which phenidone is active, it remains a reasonable alternative.
    I would then suggest Xtol as it was developed to be friendly to the environment.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

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