Ferrous Sulfate is also known as iron. It can be used as a mordant before dyeing but is used more commonly as a post dye-bath treatment to shift or sadden dye colors. It should be used at only 2-4% WOF for safe handling and disposal and to prevent damaging the fibers. For in depth information about setting up and working with an iron bath please reference pages 36-37 of my book Farm & Folk Quilt Alchemy (linked in resources below).

100 grams

Resources:

Farm & Folk Quilt Alchemy