This technique with salt is an idea from watercolour painting. It is often described in books with dire warnings against using it too often.
And I can see why: it is addictive.
When you add salt to wet paint, the crystals absorb the moisture and make a pattern. The result depends on so many variables that you can’t control the process. Relevant factors include:
- The size of the salt crystals.
- The amount of pigment in the paint.
- The amount of moisture in the paint.
- Any moisture or colour in the salt from previous uses.
- How long the paint has been on the fabric, because if any of the paint has dried, the salt won’t have any effect. So the atmospheric conditions are also relevant.
- Where the salt falls.
As the salt takes up the moisture, some of the colour is sucked out, leaving the background fabric showing through. In other places the colour of the paint is intensified. Each crystal marks its own place on the surface to form the pattern.
With these scarves, I marked some shapes on the silk in batik wax, so that the flow of colours was limited. Then I painted blends of a couple of different silk paints, letting them mix on the fabric, before adding the salt.
It is important to leave the salt on until it is properly dry, or the patterns will smudge. I try to leave it for at least 24 hours, just in case. Once the salt comes off, the scarves need to be pressed between absorbent paper to remove the wax lines and fix the colour.
Here are some pictures of the process for three different colour ways.