YOU ASKED: I am working with earth pigments specifically clay. I am trying to wrap my head around the use of soy as a binder/mordant. Is a coating of soy necessary as an initial application? Then using pigment. Mixed with soy as design than a coating of soy over the whole dried material? Or what??
KATHY ANSWERED: Soy is used as a binder, a “glue” really, to attach clay and earth pigments to a fabric surface. It is not considered a mordant as it has a different chemical process. Soy milk acts as the glue to physically hold the pigment to the surface of the textile, and mordants create a chemical bond. You can pre-treat the fabric with soymilk by brushing a light and even coat of prepared soymilk before applying the pigment. You can also mix the earth pigment powder with soymilk for additional binding power and apply it. You can even lightly brush a soymilk layer over the dried design. All of these methods will work to attach the clay pigment to the fiber and you can choose the method that works best for you.