Dr. Martin's Craft Inks are PERMANENT INKS FOR FABRIC that leave no "hand", like a dye. They are water based, acid free and have the pigment permanence to light, like a paint. Especially good for stamping, but also great for painting, spraying, etc. Great on silk, cotton and all natural fabrics as well as cotton and poly blends, and they also can be used on wood and paper. Allow to dry for 24 hours. Although they don't absolutely need heatsetting, the manufacturer recommends it. It will boost the intensity and increase the washfastness. To heat-set, set your iron to the appropriate fabric type and go back and forth with the iron for 2 minutes- do not allow it to get too hot - then stop, and repeat for 2 more minutes. The inks can be mixed to create new colors and can be cleaned up with the Cleaner. Works well with commercial rubber stamps, or better yet, make your own unique designs using any of the various products we carry. It's a great way to decorate clothing and even better when combined with another technique like tie-dye or painting for some fantastic visual texture. Non-toxic!