Quote Originally Posted by Kirk Keyes
If you are looking for tannic acid, it is actually realatively cheap commercially. 100g for $30 at Photographers Formulary, and 1 lb for $49 at Artcraft Chemicals.
Ummm. Your definition of cheap doesn't match mine, or likely that of htmlguru either (he's in college, last I checked). Formulary has Metol for about 1/4 that price (a pound is barely more than 100 g of tannic acid), which IMO doesn't put tannic acid in the "cheap" category. The Artcraft price is closer to reasonable, and there are probably other suppliers who can beat that.

And I suspect part of the idea here is related to the "making photo chemicals from common materials" meme -- making developer from acorns has a lot more cachet, even if the resulting developer is inconsistent, than making it from technical grade tannic acid that arrives in a plastic bottle. Heck, I've got enough acorns in the yard that this tempts me (though I might have missed out for this season, since the squirrels have probably long since collected the good ones).

BTW, you can extract tannins from oak bark, too, just as from the leaves. There are manys streams in the northeastern United States that look like tea as they flow in their beds, due to tannins picked up from oak roots and leaves. I'm guessing those aren't popular to drink from...