What is a mordant and why do we need it?

A mordant is a mineral salt that is used at the start of the natural dyeing process to prepare the fibre and allow the natural dye to attach to the fabric. The word mordant comes from the Latin word ‘mordere’ which means ‘to bite’.

The type of mordant needed will depend on whether the fibre is cellulose (plant) or protein (animal) based. Taking time to ensure the fabric is correctly and effectively prepared before dyeing is essential to ensure successful results when it comes to colouring the fabric. Mordanting also improves light and wash-fastness, which will give the dyed fibres colour more longevity and can produce brighter, clearer tones.

There are a number of different effective mordants and the quantities and techniques can vary between dyers. The most common mordants are; for cellulose fibres: Aluminium Acetate and for protein fibres: Aluminium Sulfate. It’s also worth noting that the PH of water used and mineral components in water from different sources can also affect your processes, so it is always good experiment and find out what works best for you.

If you would like to learn more about preparing fibres, mordanting and starting your own natural dye journey, why not join one of our Introduction to Natural Dye workshops! Dates and venues can be found on the Workshops page.