Our alum is aluminium potassium sulphate. It is a hiqh quality, scientific grade product with no iron contamination.
Alum is used as a mordant in natural dyeing and is our recommended mordant for protein (animal) fibres.
We recommend a ratio of 10g alum per 100g dry weight of fibres.
Alum can also be used in conjunction with tannin for an alum-tannin-alum mordant on cellulose (plant) fibres.