Mordanting is a very important step in successful natural dyeing – yet it is often rushed or even omitted contributing to disappointing results.
Mordants facilitate the bonding of the dyestuff to the fibre.
It provides flexibility as the fibres can be mordanted in advance, dried and dyed later – or mordanted and dyed in one day.
If you have time and patience – leaving the mordanted fibre to “cure” for a few days before rinsing results in deeper shades on wool and silk.
I do not use or recommend mordants such as chrome, copper or tin as they produce toxic waste which requires special disposal and are a health hazzard.
Mordants such as as alum, iron and tannins are safer to use and can produce multitudes of beautiful colours used in conjunction with the appropriate dye.