Aluminium potassium sulfate for mordanting cellulose and protein fibres.
Alum is used to allow the natural dyes to penetrate the wool or wool felt. It is a simple compound, with low toxicity.
Available in 250 g bottles...
Iron, as Ferrous Sulphate can be used as a colour changer. It will darken colours and increase light fastness in colours prone to fading. It can be used while mordanting or as a post dye bath...