Copper Sulfate Crystals - 2 oz
Copper sulfate, when used as a mordant is similar to iron in darkening the dye colors but it is less harsh on the fibers. Copper sulfate is sometimes listed as copper sulphate or copper vitriol.
Copper sulfate can be used on all fibers and usually improves the color fastness of plant dyes.
Copper sulfate tends to make colors greener or browner in tone.