Iron can be used as a modifier or a mordant. It can be used on all fibers and makes colors darker in tone. It also increases lightfastness and washfastness of the dyed project.
This iron powder is light green and food grade. Too much iron can harshen the hand of protein (silk, wool) fibers, so use sparingly.
iron Sulfate may also be used as the reducing agent in a traditional indigo fermentation vat, often called the “Copperas” vat.
It is also possible to create an iron acetate mordant by combining iron and acetic acid.
Keep out of reach of children.