I just finished tweaking the Acros in Caffenol C and yes an EI of 1600 is very possible, as the sample image below shows… 3200 is just a tad past my liking but for some shots it would be usable. Click on both images to see a larger view.
The dark barn boards above the windows were placed at Zone 3… they were EV 0. The detail outside the window fell on Zone 14. The detail image below is a 3″ x 3″ crop from a 20″ x 20″ print… pretty impressive.
My metering technique for these images is a stripped-down Zone approach that will be outlined in some detail in my next book The Photographers Coffee Break … I feel it fits the Caffenol C process quite well.
Figital Revolution 
Speaking of The Photographers Coffee Break, do you plan to elaborate on the S-curve as well?
Cheers,
Marcel
Marcel- my plan is an illustrated book that will not become out dated next week that outlines one possible hybrid workflow from: striped down Zone metering, film processing Caffenol C, basic scanning for max possibilities, basic photoshop with regards to the S curve and other local and global contrast controls and output considerations… the conversation will be general enough in most areas to allow for experimentation but direct enough that if you follow it from A-Z it will work every time.
Cheers-
Stephen
This is great stuff. Looking forward to seeing the book.
Great idea this, here we learn about very well features. I should just give up and take lessons from you
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Stephen,
I’ve been fascinated by the caffenol process for about 2 years now, but have been stopped by a simple lack of understanding (mainly in the “Washing Soda vs. Baking Soda” issue).
Seeing your results is heartening and I have to say that I can’t wait for your Caffenol book.
This series of blog entries was the kick in the arse that I needed.
Thank you so much,
Gregg McNeill
Isle of Bute, Scotland
P.S. Love the podcast