The Maiwa Guide to Natural Dyes
What they are and how to use them
Testing the Waters
The acidity or alkalinity of the water used for dyeing will affect the colour. This is true in the mordant bath, in the dye bath, and when washing the dyed fibre. Soft water is best for most natural dyes. The exceptions are madder, weld, logwood and brazilwood. These dyes develop better in hard water - water that contains calcium and magnesium salts.
"In places like central Asia and parts of Turkey the water is very hard. It has calcium and magnesium salts. And those cause difficulties for certain dyes, especially in the red family. This is very interesting, in the parts of the world that use madder, they have hard water, so that was their primary red. And in the parts of the world that use lac, a small insect dye found throughout south-east Asia, their water is very soft. So it is typical that the water where a red dye was developed … they had the right water for the dye." - Michele Wipplinger interviewed in the documentary In Search of Lost Colour.
For dyes that prefer hard water, calcium carbonate can be added in the form of finely ground chalk, or an antacid (Tum’s, Rolaid) tablet. Also soda ash, household ammonia, or wood ash water can be added to push the pH up.
If local hard water needs to be made acidic, add vinegar, lemon juice or a few crystals of citric acid. Water that contains iron is difficult to use for natural dyeing as it will not be possible to achieve clear, pure colours. The iron acts as both a mordant and a dye. Colours will be “saddened” by the iron and will come out muted and darker.
pH neutral (pH7) water should be used for rinsing and washing naturally dyed fibres and fabrics, otherwise there may be unwanted colour changes. A set of pH strips is a good way to test the water. When dyeing in a new studio, town or village it is wise to test the water first.
Next up - about fibres and cloth.