Scouring is nothing else but the thorough washing of your textiles. The process of removing any sizing, grease, or dirt from fibres to improve the amount and even uptake of dye.
Different types of fibres, ie. cellulose or protein, need slightly different approaches and ingredients.
General considerations when scouring
Wetting beforehand: always wet fibres beforehand for at least 5 minutes, or until they are thoroughly wetted, especially if tightly woven fabric. Allow at least an hour for wool; some would even say that an overnight soak is best. Wool fibres are water repellent to start with, yet, once wet, they hold on to the water equally strongly and will need longer time for drying than other fibres.
Changes in water temperature: when placing fibres in the water detergent, changing, or rinsing out, avoid rapid changes of water temperature, especially with dealing with wool, a sudden change will cause it to felt. This can be intentional of course ☺.
Managing different fibres: When scouring loose fibres tie the skeins loosely, and even keep them in a mesh bag. If you work with woven fabric just make sure the pieces are unfolded and can move freely in the pot.
Ratio Water/Fibre: make sure that there is plenty of room for the fibers to move, so at least about 4 litres of water to 100 gr of fibre. With tightly woven fabric make sure you ensure the piece gets good movement.
Preparing detergents: stir detergent and washing soda first in some warm water to dissolve, before placing on the large pot with water to match the temperature of your fibres from your soaking bath.
Using a washing machine: When working with cellulose fibres, you can keep it simple and wash the fabric in the washing machine in hot water with soda ash. The added benefit is that it will clean the interior of the washing machine very nicely ☺ .
How do you know if scouring is good: Once finished, if water still looks a little brown it is best to have a second go with new ingredients. Rinse out all soap suds until the water runs out clear.
Once scoured, the fabric can be used straight away, or left to dry and store for future use.
Some dyes are substantive, i.e. do not need an assistant to attach themselves to the fibres. However, most dyes are adjective, i.e. they need a chemical bridge that will hold them together within the fabric. We are transforming a soluble dye into an insoluble pigment attached to the fabric.
You are now ready for an important step before dyeing cloths: mordanting.
