Okay, so I've got some ultramarine blue and violet. I understand that the two of them combined will make a nice purple. I'm wanting to make a lemon/lavender soap, and have it with a bright yellow background with a purple swirl.
So here's my question (I know you were wondering when I'd get to that!

). Is the best way to combine them to take a bit of each color's powder/dust/whatever (what DO you call this form of the stuff??), mix together, pour some of your raw soap in, and mix well? Or are you better to pick one of the colors, mix in the raw soap, and then add the other color until you like what you see?
Or does it really make a hill of beans' worth of difference how you do it?
Thanks!
Anita