When you start to be interested in the world of natural dye, you will hear a lot of times that mordanting the fabric before dyeing is extremely important; but when you started looking about how to mordant is normal to feel overwhelmed with all the information available, mordanting seems to be difficult to understand and hard to do, and is normally
the part of the process where everyone gets discouraged about natural dyeing.
But mordanting doesn't have to be complicated; Here I'm going to explain one of the methods I use to mordant my cellulose fabric.
( In my studio, I use two methods to mordant: one with potassium alum and the other one with aluminium acetate, in this blog post I'm going to explain the second method with aluminium acetate, to learn the potassium alum method click here)
Mordanting cellulose fibres.
Mordantin cellulose fabric is a two-step process, the first process consists in applying a "layer" of tannin extract, then the second step consists in applying Aluminum acetate
The tannin extract will create a weak bond with the fibre, but then when the Aluminium Acetate is applied this bond will become strong.
We are going to need:
A cellulose fabric or yarn, like cotton or linen
10% WOF in tannin extract, I'm using Gallnut extract
5% of Aluminum acetate
Two plastic vessels that are big enough to allow the fabric to move inside.
A wooden spoon
A kitchen scale
A Glass jar (like the jams one)
Facemask and gloves
*WOF = Weight Of Fabric.
Remember to weigh the fabric before washing it.
Note before we continued:
-Aluminium acetate is a very fine powder, so use a facemask when measuring and mixing to avoid breathing it.
-Cannot find aluminium acetate? use potassium alum instead, click here to learn how.
STEP 1_ Application of tannin extract
First, we have to scour the fabric. To do this simmer the fabric for at least two hours in a solution of two teaspoons of washing up liquid and one teaspoon of washing soda. then rinse thoroughly several times to remove all the dirt.
Fill one of the plastic vessels with hot water ( around 40°-50° Celsius) using a radio of 30:1 of water: textile. This means that if your textile weighs 100 grams you will use 300 grams of water. ( 300ml)
Add the tannin and dissolve until the solution is well mixed.
Place the textile in the solution and let it soak for 1-2 hours, there is no need to reheat the bath, just let the fabric to cold inside)
You can use a ceramic place to avoid the fabric floating over the water surface.
Remove the fabric from the solution using rubber gloves, then squeeze the excess water back into the vessel.
Rinse lightly or spin in the washing machine, then mordant the fabric right away.
STEP 2_ Mordanting with Aluminium acetate
Fill the other plastic vessel with enough hot water to cover the fabric. ( around 40°-50° Celsius)
Dissolve the 5% of AA in a glass container, one is all dissolved add the AA to the vessel
Immerse the textile inside the bath and let it soak for 1-2 hours. there is no need to reheat the water, let the fabric cold inside the vessel.
Remove the fabric using rubber gloves
Rinse the fabric very well to remove the unattached particles of Aluminum acetate
After that, the fabric is ready to be placed in a dye bath immediately or can be dried and saved to use later.
As you can see is a really easy way to mordant cellulose fabric, I recommend to mordant more fabric that you need, so you always have fabric ready to dye.