"Albino" Caffenol failure and questions

Discussion in 'B&W: Film, Paper, Chemistry' started by dorff, Sep 2, 2012.

  1. dorff

    dorff Member

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    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:confused:. 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:blink:. 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. Steve Smith

    Steve Smith Subscriber

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    It's not the caffeine in coffee which develops film, it's the caffeic acid.


    Steve.
     
  3. dorff

    dorff Member

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    Thanks for the clarification, Steve! Oh well, I could make a few energy drinks with my caffeine stash :smile:. 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. Gerald C Koch

    Gerald C Koch Member

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    The reason why people use instant coffee is that caffeic acid is not readily available.
     
  5. BradS

    BradS Subscriber

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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. Steve Smith

    Steve Smith Subscriber

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  7. BradS

    BradS Subscriber

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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. Gerald C Koch

    Gerald C Koch Member

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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.
     
  9. dorff

    dorff Member

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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. Gerald C Koch

    Gerald C Koch Member

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    I would then suggest Xtol as it was developed to be friendly to the environment.
     
  11. dorff

    dorff Member

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    Hi Gerald,

    Fair enough, and I appreciate all the info that you have shared. Xtol is expensive and only sporadically available in South Africa. Because of the weight, it is quite expensive to import directly. It doesn't seem to be available in 1 liter quantity any longer, which is a pity, as one could have sneaked in a small packet with a film order without affecting the shipping cost that much. It was more for the fun of trying something new that I went onto the "albino" caffenol tangent. I was also hoping to make a paper developer similar to Patrick Gainer's formulas that are based on phenidone, and for interest's sake will still give it a go if I can get suitable material without too much hassle. There is little point in exploring impractical options. Let me see if the wild goose chase lands us a goose - if it doesn't, then none of us are any worse off.
     
  12. ME Super

    ME Super Member

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    There's a thread here about someone's experiments with edible developers. How's that for environmentally friendly?
     
  13. jnanian

    jnanian Advertiser Advertiser

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    hi dorff

    instant coffee is usually made of robusta coffee beans, not arabica beans.
    just try to find the cheapest instant coffee you can find, around here
    it sometimes goes for $1USD/jar.
    if cost is a factor for you ( for the coffee ) see if you can make friends
    with a coffee roaster and get GREEN coffee beans. you can roast them on your grill
    or stove in a pan / wok, or in a popcorn popper, and just make a pot of coffee ( 2tbs/ cup as you would
    with coffee you drink ) and you will be using the best caffenol and least expensive caffenol you can buy.
    i use beans, not instant, and i would be happy to send you some, but i have a feeling shipping &c will
    be excessive, and cost more than buying it local ...

    good luck !
    john
     
  14. dorff

    dorff Member

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    Hi John,

    Thanks for the kind offer. I know of a local importer of raw beans, and will see if I can strike up a friendship. Usually the surprise value of the end use is enough to win someone over. I was hoping to make a clear developer that is also suitable for paper, but right now that isn't a particularly high priority. If the caffeic acid is already present in the green bean, then presumably one can circumvent the roasting process (which also potentially destroys some of the active ingredients). Another possible route is to ask a production manager at a coffee factory that produces decaf, if one can have a few hundred grams of the extract including the caffeine, before it is worked up further. However, I have no idea whether the form is oily liquid, goop, powder or whatever. I assume the extraction involves supercritical CO2. Which makes me wonder: If it works for caffeic acid, shouldn't it work very well for rosmarinic and other potential developing acids? I know of a local gang looking at essential oils and other extracts from our local aromatic plants (Pelargoniums, many plants of the sage and citrus families etc.). Maybe a quick call to them might be of use. Anyway, that's a topic for another day. I have also wondered, since the pure compounds are sometimes rather insoluble in water, whether boiling the coffee beans, rosemary, mint or whatever, in a weak hydroxide solution will allow better extraction as it will produce the conjugate ion (caffeate, rosmarinate etc.) that should theoretically be more soluble. Have you tried this with coffee beans?

    As for cost: It comes to R45 (roughly $5) per 200 grams for instant coffee, so close to $1 per liter of developer. Not high and not low. By comparison, it is cheaper than Xtol and more expensive than Rodinal. I think most people using caffenol have a motivation other than cost or convenience, at least that is how it seems.

    Thanks for the encouragement.

    Jaco
     
  15. jnanian

    jnanian Advertiser Advertiser

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    hi jaco

    make sure ... if you get beans from a local roaster
    that the "line" isn't curved but straight. the curved line
    is arabica the straight ones are robusta. ( the line on the flat underside of the coffee bean )
    i presently use half roasted, half green beans when i make caffenol.
    i mix a very strong batch and probably over add vit c and washing soda.
    it's a mix of 22 tablespoons of coarse ground coffee in a 10cup perk ( roughly 750cc 1 coffee scoop / cup + 1 for the pot
    as i would when i make coffee to drink ) i add about 3oz of sodium carb and maybe 2/3 that amount of vit c ( i add until it foams then i stop )
    i also add in 10-15cc of ansco 130 print dev / L of caffenol. it comes out to 4ยข/ sheet-roll &c of film
    and i process my prints in it too .. it lasts between 3 and 6 months without replenishment ...
    i always have 2L and when i feel i want to make more developer, i take 1L out, and add 1L in ... hasn't failed me yet

    for the instant, the arabica is just added to make it taste better, the cheaper has less arabica and more robusta.
    when i was in france " old gringo" brand was the bottom of the barrel, the cheapest and made great developer.

    to answer your questions about boiling and make a solution &c ...
    nope i have never done anything more than just dump the ingredients in a vat
    and mix them up :smile:

    your roasting plant idea sounds interesting, but i don't know
    there might be other things, aside from just the caffic acid that play a role
    in caffenol. i've been using it for 6+ years now and while i have a system that works for me
    i am pretty much a babe in the woods ...

    good luck !
    john
     
  16. dorff

    dorff Member

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    Hi John,

    Thanks for the additional info - I will most definitely give it a try once I can get robusta beans. My parents' garden where I grew up had a coffee hedge - the house is now long sold. Had I known then ;-). Coffee is grown in South Africa (in limited quantity) - I just need to find out whether the robusta variety is readily available. Since we aren't discriminating about the taste here, the bottom rung of the price ladder should suffice.

    We do have a coffee grinder, which will soon be put to good use. I am thinking that it is probably necessary to bake the green beans at low heat (ca 90 deg C) just to thoroughly dry them before grinding, otherwise it will be like making peanut butter. As for paper developer, I am thinking that using only green beans should give a developer that is clear enough not to stain the paper too much. OTOH, the stain might add to the charm of the print in some cases. But it would be preferable to have control over that.

    After reading the "Edible Film Developers" thread I am now a bit wiser as to what might and might not work. My point of departure is that whatever one uses must be practical, as that usually outlasts the charm of doing something outlandish. I think caffenol strikes a nice balance between the two.

    I am a chemical engineer (disclaimer: I last touched an organic chemistry textbook twenty years ago) and it should be comparatively easy to design an extraction system to automate all of this. That said, it is difficult to achieve this on the scale that can be practiced in a kitchen, darkroom or garage. That is where I hoped a hydroxide extraction would make for an easy way to get the active ingredients out of aromatic plants, as that can be done on a stove. We are only interested in developing chemicals, not all the other oily aromatic substances too. Just about all of the developers are active as salts of an alkali metal, if I understand correctly. I'll try with mint, rosemary and whatever else I can find in our garden, and I will post the results at some stage. To be clear, I will specifically use something like 2 grams/liter of KOH for the boiling part, and then I will add ascorbate typically in the caffenol quantities to increase the activity. I have a good reference standard for ascorbate only, so should be able to instantly see an increase in developer activity.

    Regards,
    Jaco
     
  17. pdeeh

    pdeeh Member

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    there are a couple of active Caffenol groups on Flickr (if you concern yourself with hybrid process) which I think would welcome hearing about your investigations.