Lately I received a bar of soap made by a friend. It is colored a vibrant pink, the kind of pink that makes you think of marshmallows and candies. What she did was dissolve some fuchsia colored silk fabric in her water-lye solution. I have no idea how this worked for her, I never tried it myself but the soap is excellent. Has a nice slip, lathers just fine, smell is good, does not strip my skin of its natural oils and produces a slightly pinkish lather.
Now I 'm really itching to give it a try, I especially want a deep red soap but I am a little reluctant. I'm thinking it might not be very mild on sensitive skin (you never know what kind of dye the fabric manufacturer used) but I will eventually make a small batch just to see how it works.
If you do please let us know how it went!