Tannin extract is most commonly used to strengthen the bond of the aluminum salt to the cellulose fiber to be dyed, increasing the resultant depth of shade and fastness. The Earthues tannin extract is composed of 50% sumac (Rhus coriaria) and 50% mimosa (Acusia mearnsii) and produces a light tan color.
When tannin is introduced to an iron after-bath you can get a beautiful range of grays from light to dark. Tannin can also be used in a 2-step mordant process on cellulose along with aluminum acetate for better color uptake and light-fastness.
Color: Tea to Silver Grey