Green Coffee Does Work!
I guess it's not a big surprise, but the developer made with green coffee beans works! At least with paper, it is similar to developer made with instant coffee and carbonate of soda.
Here is what it looked like after steeping in the bottle for a day:
After filtering, there were 9 fluid ounces of liquid. The beans became pale and lost their green color:
I used one ounce to do a coin test. A test strip was exposed to room light with a coin on each end.
On the right side I used 1 oz green bean tea and 0.66g soda. Under a safelight, after 4 minutes I could tell it was going to develop more than soda alone. After 7 minutes it was easy to see it was getting black, and after 10 minutes it was still getting darker and I thought it had reached a black. Then the left side was also developed for 10 minutes, but in 1 oz of water with the same amount of soda added. You can clearly see that the green bean side was more active than soda alone:
But that's not the end of the story! This is a very strange brew! When you first mix in the soda, it turns a bright orange color, just like orange juice. Then when you use it to develop the paper, it turns a dark almost lime green color! Also, after mixing the soda in, you can see it turning darker orange as you watch. The soda must activate something that oxidizes quickly. However, between 7 and 10 minutes development the color is already dark green but it is still developing the paper, so the dark green color might not be directly related to development activity. It would be interesting to know what's going on with that color.
Here is the bright orange color just after adding the soda:
And here is the dark green color after developing a piece of photo paper for 10 minutes:
I made 3 pinhole paper negatives this afternoon at the beach. Unfortunately, midday at the beach in the summer is tricky with paper negatives and I overexposed the first one terribly. The second one was also overexposed but might be salvageable. The third one came out well and I'm hoping it might have a "suggestion" of sand, sea, and sky for the current MSA.... we'll see.
I used 1/3 cup of the green bean liquid for each. For the first two, I added one teaspoon of soda. For the third one I added 1/2 teaspoon
*, and my impression was that this might be better ( hard to say since it was also the only one not overexposed.... but my gut feeling was that there was nearly as much development due to the coffee, but less initial "haze" due to the soda, and that it was cleaner and under better control for development by inspection. ) I developed each for 10 minutes.
If you try this, I recommend starting with 1.5 teaspoons ( 8 g ) soda to 8 fl. oz green coffee bean "juice" ( about 235 ml ) and adjust from there.
The negatives are drying now and I'll post the two that were not ruined later tonight or tomorrow.
*(
technical detail): I made a mistake when I did the coin test. One teaspoon of sodium carbonate weighs about 5.3 g. I intended to test at a concentration equivalent to 3 teaspoons per 8 oz., but I forgot to multiply and so the coin test was done with only 1/3 the concentration of soda. I realized this after I'd already developed two of my paper negatives, so that's why I reduced the soda for the third. I think as well as overexposure, there may be some fogging on the first two. The third one looks clean, like the coin test.