view of a forest in summer

Tannins as Natural Mordants

Tannins or tannoids are a type of mordant that naturally occur in plants. If you are dyeing protein (e.g. wool) or cellulose (e.g. cotton) fibers with natural dyes, you need a mordant or fixative to help set the dye on the fiber. The mordant forms a coordination complex with the dye which attaches to the …