June 17, 2010

Reducing pH for highspeed films? Fomapan 400

I decided to delete the recipe, since Caffenol-C-L is much better.

PS: I also deleted the recipe because my notes about it were not correct, as I said here before. Restoring impossible. That was never a reliable recipe. So save any angry comments. Sorry for any unconveniance. I don't follow this path any further. But general thought here still might be of interest.
Some people suggest reducing  the pH to reduce fog and grain. Borax is suggested as a mild alkaline. My first trials with borax were not encouraging, but why not reduce the soda? So I made a somehow "lighter" Caffenol-C-M, hoping to tame the developer with highspeed films. No scientific approach at all. I took a Fomapan 400 as 120 film, loaded my 65 years old Bessa 66 and shot the roll without metering the exposure. To be honest, I forgot my meter at home. All 12 images were nicely usable, though about 1/2 was overexposed. I estimated for 400 ASA, maybe the Fomapan 400 should be rated higher. OK, only one film, and my first Fomapan400 in Caffenol.

This pimped Caffenol-C-M contains 1/2 of the Vit-C and much less soda, but the same amount of instant coffee as before. pH is 9.2 instead of 9.7 before.  If we go below a certain pH, development will probably stop completely. This point I still have to examin. For low pH-Caffenol it is more important to measure the soda exactly and use the right one, be it anhydrous or hydrate with recalculated amounts - see "soda-myth-and thruth"-post.  Because the lower the pH, the smaller the different amounts of soda to make big changes. I hope you got a weightscale in the meanwhile ;-)

Results: low fog level, grainy but "nice" grain, sharp, wide tonal range, probably more than boxspeed.

Click on the images to enlarge as usual. Crop is 10x10 mm neg size. 3 more images on Flickr.

Have fun with coffee - Reinhold

June 12, 2010

Who invented coffee based development?

When asking myself who invented Caffenol, I stumbled across an article by Dr. Scott A. Williams Ph.D., Rochester Institute of Technologie (R.I.T.). The Technical Photography 1995 Class under the leadership of Dr. Williams should research non traditional developers based on household ingredients and after some unsuccessful trials they decided to test drinks with caffeine like tea or coffee. Coffee was the winner and that was the beginning of coffee based developing. They used baking soda and potassium hydroxide for buffering the pH of 9. The name Caffenol wasn't yet created. We now use the more conveniant washing soda as pH adjusting agent, and the later addition of Vitamin-C since about the year 2000 improves the image quality dramatically. If you want to read the whole article, look here: http://people.rit.edu/andpph/text-coffee.html

The article is pure text without images, but refers to images that once must have been attached. I searched the web to find the lost images, but couldn't find them. So I decided to contact Dr. Williams via email and he sent me the original article, published in "Darkroom and Creative Camera Techniques", issue Sept/Okt 1995, with the kind permission to publish the images here on my blog. I don't want to bore you with scientific figures of molecular structures, but I'm pretty sure that you are curious who the people were and looked like. So here we go:

You deserve our highest appreciation

Thank you so much. Best regards - Reinhold