Mordants

“Step by step one goes very far”

Scouring fabric outside in garden

 Definition of mordant:  Biting and caustic in thought, manner, or style. The word derives from the french word mordre which means to bite. In natural dyeing a better way to describe is "a metallic salt that combines with a natural dye to form a pigment" (reference Maiwa).


Mordants are another key process to getting the best results from your fabric and dye. And yes this is another step where you wont see any colour change on your fabric. A good understanding of the mordants and the process will give you the fullest potential from your dye and a wider range of surface pattern techniques.

Mordants are the key to getting the lasting colours.

Not all colours are fully formed in the plant and in a lot of dyes it is not a case of just getting the colour you see from the plant onto a piece of cloth. Natural dyes just don't work this way, it is more about a process of metamorphosis, in which you need a fiber, a natural dye, and a mordant (unless using Indigo).


The dye is from organic matter (something living)- a plant / animal.

The mordant is from something inorganic (not living) - a metallic salt.


Both the organic and inorganic elements need to interact with each other to make a permanent colour. This interaction is more than just sticking colour onto fabric, the mordant is not like glue.


Mordants are metal salts which are dissolve in water. Natural dyes also start as soluble, however when you combine the two you get an insoluble pigment, which is insoluble and therefore does not dissolve in water at all. The key is getting this reaction to happen on the fabric itself. Thus creating a dye that will stay permanently on the fabric and not wash off.

Some mordants are clear like Alum, and some have colour like Iron and Copper.
 
For protein fibers - Silk, Wool and Leather I like to use Potassium Alum Sulfate ( Alum).


Potassium aluminum sulfate is a safe mordant and one that is frequently used by natural dyers for protein (animal) fibres. However it can also be used for cellulose (plant) fibers and fabrics. It helps improve the light-fastness and wash-fastness of natural dyes and helps keep clear colours. Potassium alum is commonly used in water purification, leather tanning, and baking powder as the E number E522. It also has cosmetic uses as a deodorant, as an aftershave treatment.It has been used as far back as the Early Egyptians around 1500 BC. More history on Potassium Alum - HERE

Make sure when buying it is pure Potassium Aluminum Sulfate I personally like to  use at 15% WOF.

 
For cellulose fibers - connton, linen, hemp and bamboo I like to use Aluminum Acetate


Alum Acetate is my preferred alum mordant for my cellulose fabrics. I find that it can give cleaner and richer results. I also find it gives better results when used for fabric that is printed or eco printed onto. I like to use at 8 % WOF.


"The only faith that wears well and holds its color in all weathers is that which is woven of conviction and set with the sharp mordant of experience."

Leave a comment

Please note, comments must be approved before they are published