When you use a powdered colorant for fizzies or salts, the bath water will be tinted as well.
Stir gently to allow the colorant to melt at the same time as the soap and ensure an evenly colored product.
After adding the colorant, stir the mixture until it is completely blended, and then repeat the process as necessary to get the color you want.
You will usually need more colorant with a white base than with a clear base.
Raw spinach is also being used as a natural green colorant for soaps and candles.