Mordants

MORDANTS

Mordants are chemical compounds—usually metallic salts—that can be mined or obtained from plants that accumulate metals. Textiles soaked in a mordant will hold onto dyes more effectively and enduringly. Mordants containing different metals will produce different colors (see mordanted samples in this case). Fibers mordanted with iron tend to produce a darker, grayer color; fibers mordanted tin produce a slightly different color of red. Even the metallic content of the dye pot can mordant fibers in different ways. A copper pot may brighten dye colors, while an iron cauldron will darken them. 

— Written by Sarah K. Rich (Art History, Center for Virtual/Material Studies)