Many soapers and crafters got into their craft because they wanted to make and use the most natural products possible, and to be able to control what ingredients are in the products they use. One way to do that is to use herbs and other natural colorants in products. They can be a bit unpredictable, but are also fun to use and can yield some very beautiful results.
Here are some natural colorants to use that will yield black and white tones in your product:
Kaolin clay – white
Titanium dioxide – bright white
Poppy seeds – (dried, powdered) – black. Cute small black polka dots when used whole