I was just playing with natural coloring agents for soap. I tried Beet Powder, Red Henna, and Clove. I also bought some tumeric, but haven't tried it yet.
Anyway, they made some lovely colors (i'll put up a pic later)
but they didn't mix very well.
For those of you who use powder colors, how do you mix them?
here's what they ended up looking like http://www.wahmall.com/auctions/userpics/lalasoaps.jpg
I got some natural soap pigments from a herbal supplier in the US when I was doing an order a few years back. I've been using them in my bath bombs too. They work really well. With the powdered beets etc, I'd guess it may be better to make a strong tea out of them with the water you're using in the soap?