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Caffeine Reduction Chemistry

Denton Hoyer , Mar 09, 2006; 08:38 p.m.

Anyone have any idea what is actually being oxidized in a coffee developer? Is the caffeine being oxidized, perhaps at the imino carbon or are the polyphenols the likely source of electrons? Seems like the better developers contain a reductant in higher stoichiometry and the coffee serves as an intermediate?

Has anyone tried coffee/caffeine with paper development?

On another note, this may explain the antioxidant properties of drinking coffee.

Peace, Denton


Jordan W. , Mar 09, 2006; 10:30 p.m.

Denton -- Coffee has all kinds of polyphenols in it, and I think that it is those that are the main "antioxidants" (in the biological sense) in coffee -- and I think they are present in wine and tea as well.

But the main reducing agent (in the photographic sense) in coffee is thought to be caffeic acid, which is unrelated to caffeine. You sound like you're a chemist -- so you'll know what I mean when I say that it exists as a glycoside in the coffee bean, but the parent acid is (IIRC) 3,4-dihydroxycinnamic acid. That ortho-dihydroxylated aromatic ring is what's doing the developing -- just like catechol does.

AFAIK caffeine on its own is not a strong enough reducing agent to develop film. I think I remember reading (here or at APUG) that someone actually tried developing film in a solution of No-Doze, and that it did not work.

Manfred Feuser , Mar 10, 2006; 02:24 a.m.

Thank's Denton & Jordan. Most interesting except I dont understand most of it. Still now we know the stuff does not develop paper , can we still drink it it seems to have the antioxidants after all. I drink gallons of this brew and really like to be sure.

Jordan W. , Mar 10, 2006; 09:33 a.m.

Manfred, a solution of instant coffee and washing soda in water (I can't remember the proportions -- maybe 4 tsp of instant coffee and 2 tsp of washing soda per cup?) -- will develop film in 25-35 mins to give a stain image (like PMK or Pyrocat) with somewhat coarse grain. We were discussing which constituent(s) in coffee is/are responsible for the development.

Lex Jenkins , Mar 10, 2006; 03:38 p.m.

If you check the archives of the B&W Photo - Film & Processing Forum you'll find quite a few discussions of homebrewed developers, especially using coffee. It's pretty interesting stuff.

melvin bramley , Mar 10, 2006; 06:56 p.m.

Whatever keeps you awake

I do not wish to make light of the original post but the idea or thought of using coffee as a developer just makes me smile. Could it be that we will have a Tim Hortons vs Wendy's vs McDonalds print test? The possibilties are endless!Perhaps we can use McDonalds Coffee for a normal looking print but tea for a softer looking;or 1/2 grade reducing developer.Have a good weekend guys & don't drink too much in the darkroom; you may not sleep too well.

Steve Johnston , Mar 10, 2006; 10:14 p.m.

I love to read these discourses(sp?) I want to start brewing my own developer. What is holding me back is my lack of fundamental information about how each of the component chemicals act in relation to each other in the context of a film/paper developer. I cannot seem to glean that info from Anchel's Cookbooks. Also, with my limited intellect, I have difficulty with words exceeding seven syllables. Thanks in advance.

Lee Crump , Mar 10, 2006; 11:00 p.m.


A good site for this kind o' stuff!

Steve Johnston , Mar 11, 2006; 07:13 a.m.

Lee, Many thanks! Great resource.

Lex Jenkins , Mar 11, 2006; 12:00 p.m.

I'll bet that data for caffenol (caffeinol?) on the Digital Truth site came from photo.net members who worked quite a bit on finding a consistent recipe for this homebrew.

I need to try this myself. My only experiments with homebrewed developer contained nasty stuff like lye. The results weren't too good. Negatives had a lot of fog and the stuff infiltrated the edges of my prints, staining them.

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