>THanks so much for the reply. Well, here's the
>added difficulty. I want to stick to
>non-manufactured pigments, so the question
>becomes, can you think of a way to get to the
>nice terracotta using the ochres and natural
>reds, etc.?

Those are the only ones that you can use (ochres, red oxides, mars, etc...)

what do you mean non-manufactured?

You need ONLY (lime in the plaster will "eat" (destroy) any synthetic or organic pigments) natural earth/minerals and those Mitch are refers to and those are the only ones to use... You dont have to grind rocks yourself...
unless you find a clean and pure deposit of a certain mineral, then you better put a factory there