Salt is important in high-volume immersion dyeing, because otherwise the dye tends to spend too much time in the water, and not enough actually contacting the fiber. This is because the electrostatic charges of the fabric and of the dye are similar, so they tend to repel each other, but a lot of salt in the dyebath helps to overcome this problem. Omitting the salt means wasting a lot of dye.
When you use only a very small amount of water, such as in tie-dyeing or low water immersion, you can get by without salt.
Using too much salt might reduce the solubility of the dye. Using too little will not work as well. Find a recipe and follow its recommendations. One cup (250 ml) of granulated salt is a good amount for every one gallon (4 liters) of dyebath. Dissolve your dye before adding the salt.
Paula
