Water soluble tannin for cotton mordanting and black. Also used as a beige base for block printing with an iron solution.
Use at 20 to 25% by weight of fabric. A cold soak overnight, with a few stirrings, is usually adequate to impart a good beige base to any natural textile fibre. In cotton dyework, a combination of alum mordant with a tannin base gives the richest and most permanent colours.
All mordants we supply and use are from naturally occurring minerals that come from the Earth. When the fabric biodegrades the minerals will return to the Earth from whence they came. There are no residuals left on the fabric as the minor amount of fixative is locked into the fibre.
For more information please see the article "The Myth of the Bad Mordant."