Much to the bane of crafts people everywhere, acrylic paint tends to stiffen and crack when used to paint on material. This is especially true when painted on material that must be washed and dried. While there are acrylic paints made just for painting material, most people already have a cabinet full of acrylic paint. Instead of having to purchase all new paint, purchase some textile medium to turn your regular acrylic paint into fabric paint that will not harden when applied to fabric.
Pour a medium-sized puddle of acrylic paint on a plastic plate.
Add textile medium directly to the center of the puddle of acrylic paint. Add about one part textile medium to two parts acrylic paint.
Mix the paint and textile medium together thoroughly using the large end of a stylus or a toothpick.
Dip the paint brush into the mixture of paint and textile medium and apply to your material.
Allow the painted material to dry completely for at least seven days.
Place the painted material between two sheets of white paper and heat set by ironing with an iron set to the fabric setting.
Use even pressure when ironing the painted material. When painting clothing, insert cardboard between the layers of fabric to keep the paint from bleeding onto the other side.
Wash all material before painting to remove sizing. Do not use fabric sheets.