|Native American basket makers have used oak galls boiled in water to make a dye. They also have used a rusty pan (iron) to make it darker. The galls have been powdered rather than cut up in pieces or used whole. Another way is to use a combination of ether and alcohol (watch out for the ether) but I don't know the ratio but assume it to be 50/50. That extracts the gallic acid from teh galls which is then very miscible with water. I'd refrain from using iron if you boil the galls for the iron can make speckles of stains like we have seen in cyanotypes from using water from the tap that includes small particles of iron coming from the pipes in the house.|
Chris is right in using walnut husks for they contain the acid as well.
Here is some info garnered from an on-line encyclopedia:
Common tannin, or tannic acid, C14I-i1509.2H20, occurs to the extent of 50% in gall-nuts, and also in tea, sumac and in other plants . It may be obtained by extracting powdered gall-nuts with a mixture of ether and alcohol, whereupon the tannin is taken up in the lower layer, which on separation and evaporation yields the acid . When pure the acid forms a colourless, amorphous mass, very soluble in water, less so in alcohol, and practically insoluble in ether .
On Aug 23, 2008, at 10:34 AM, Christina Z. Anderson wrote:
I did not use oak per se but I used walnut husks and boiled a cup or two of them in a bunch of water for a while and used the water as the toning bath. I got my walnut husks from a basket maker. The method is very loose because in basket lore, a basket maker would just have an old barrel filled with rain water and toss the walnuts in that and then use it for dyeing. It is very archival. I have NOT done this with cyanotype but with gelatin silver prints so I cannot guarantee it will directly apply to your situation.
I have toned with gallic, though, that I bought from Artcraftchemicals.com
Hope this helps,
----- Original Message -----
Sent: Saturday, August 23, 2008 11:12 AM
Subject: Re:Gallic acid; Was:
Speaking of toning cyanotypes, I recently gave a cyanotype workshop for my book arts group, and we did some toning with tannic acid, using tea. I mentioned that gallic acid was also sometimes used but I'd never tried it. Well, someone from the group just gave me two bags (!) of oak galls. Does anyone know how to extract gallic acid from oak galls-- or even if it's possible?
On Aug 22, 2008, at 5:08 PM, Robert W. Schramm wrote:
BTW cyanotype can be toned to achieve colors other that blue and white.
Good luck with your work and welcome to alternative process printing.