Copper Sulphate Powder

Copper Sulphate is used as a mordant in natural dyeing. A mordant is a substance, typically an inorganic oxide, that combines with a dye or stain which allows plant pigments to bond with the fibres. Copper Sulphate turns fibres blue green, for example yellows become greens, pinks become purple. The resulting colours are very lightfast, with much brighter shades compared to using Alum.

How to use copper sulphate as a mordant?
For every 250g of the dry wool or silk, use 5g of copper sulphate in 5 litres of water. Add 10g of Cream of Tartar to help soften the fibre and brighten the colours. Gradually heat the mordant bath to around 80°C for 30 minutes and allow to cool slowly.

Disposal of Copper Sulphate baths
Copper is toxic to marine life as well as humans and needs to be disposed of carefully.  Exhaust all dyebaths by diluting with clean water and never put it down the storm water.