Quercitannic acid
The bark from the oak tree produces tannin which was traditionally used for tanning leather. Tannin is a common mordant used in the dyeing process for cellulose fibres such as cotton – often combined with alum and/or iron.
Quercitannic acid is one of the two forms of tannic acid found in oak bark and leaves. The other form is called gallotannic acid and is found in oak galls.
An ancient method for dyeing with wood bark is known as the fermentation method. It is a lengthy method – but very satisfying.
Add 1 teaspoon of soda ash to 100ml of hot water. Stir to disolve and add 1 litre of cold water then transfer to a dye bucket. The pH should be 10. Adjust soda ash if required.
Add 100g of oak bark – stir well and cover the bucket with a lid. Stir daily. Do this for 3 – 4 weeks.
As the bark ferments the pH will become more acidic – so when necessary add a little more soda ash (dissolved in hot water). Maintaining a pH of 9 – 10.
In the 4th week allow the pH to drop to 7 for a week – then strain through a cheesecloth. This is your dye bath solution.. Keeping the contents of the cheesecloth in a bundle, rinse and squeeze in fresh water to retain as much dye content as possible. Add this liquor to the dye bucket until you have enough solution to cover the fibre.
Add your pre-wetted fibre and leave in the bucket for 2 -3 weeks – strir daily – ensure the fibre remains submerged.
When you have achieved the colour you desire remove the fibre from the dye bucket –
Rinse. Wash. Rinse.
Dry out of direct sunlight.
ALTERNATIVELY:-
100g of fibre – mordanted
50g of oak bark
Pour boiling water over the bark and leave to soak overnight.
The following day gently simmer for 1 hour. Leave to cool.
Strain through cheesecloth.
Pour liquid into dye bucket and top up with sufficient water to cover dye material.You could use the contents in the cheesecloth to create the additional water for the top up by rinsing and squeezing the cloth in water and pouring it into the dye bucket.
Add pre-wetted fibre.
Raise temperature to gentle simmer. No more than 140 degrees F. Hold for 45 minutes.
Turn off heat. Leave to cool.
Rinse. Wash. Rinse.
Dry out of direct sunlight.
