[alt-photo] Re: coffee and cyanotype

[Ryuji Suzuki]

How much tannic acid do you use in the tannic acid bath? Loris mentioned 
teaspoon in 2 liters. I think that's too much. You could probably get enough 
reaction with 0.1g/L to 0.5g/L or something of that order, as long as you throw 
in a bit of borax or carbonate to adjust the pH to 9 or 10. Tannic acid itself 
is acidic (usually pH 3 to 5) when dissolved in water.

... and if you say your coffee is cheaper than tannic acid, I'm not sure what 
kind of coffee you're drinking! It probably does not help sharpening your mind.

--
Ryuji Suzuki
"Don't play what's there, play what's not there." (Miles Davis)


Christina Anderson wrote:

> What I think interesting, in answer to Ryuji's question of why not tannic acid is this: I have always used tannic and gallic as per Ware's suggestion that these two were the most archival...I have them in pound jars, very easy to use. But Rob mentions DEVELOPING in coffee (no wash water first and toning later!) and that is what intrigued me.  I think developing in a tray of tannic or gallic would get costly as you'd have to throw the tray after a session as it gets all blue. I keep a gallon of the tannic mixed up. But everyone (mostly) has leftover coffee in their pots on a daily basis so how cheap would that be!