I want to demonstrate a watercolour technique which combines science, art and nature, repeating themes of these pages at simonmitchell.co.uk. This is the effect of salt on a watercolour wash. This effect creates a stunning texture which can be used in a number of ways including that of a generalised ‘nature’ texture / background.
Firstly you will need to experiment with your watercolour palette to see which of your pigments react the best to salt. Mix up some base (unmixed) paints from your palette and, one at a time, fill a small shape with paint and sprinkle salt on it. Wait for it to dry to see which colours works best.
The other variables in this process are the dryness of the salt and the absorbency of the paper. You can increase the absorbency of the salt by drying it out in a pan previous to the painting. On the whole, crushed (and dried) sea salt seems to work the best for me and I tend to use Bockingford 90gsm paper. I haven’t yet experimented with paper that has a high clay content.
In the example flower painting opposite I used masking fluid to protect the edge line of the flower. There isn’t a lot of time when using washes, to paint around things! As soon as the wash shows signs of drying, sprinkle the salt into the places where you want the effect to occur and leave it to dry. If you have stretched your paper on a frame, you can speed things up a bit by using a hair dryer or placing your painting (safely) in a warm air flow. Place it horizontal, unless you want drips.
Once the background is dry, remove the masking fluid and continue with the painting.
The next example shows UGLY, a steam engine at the Bodmin and Wenford Steam Railway depot. The salt wash background worked particularly well on this, using Hookers Green Light watercolour in a tube. Underneath that is a detail from the painting.
Finally in this selection of examples from my personal painting archive is a small ‘wet in wet’ salt wash which used table salt rather than sea or rock salt, with the details picked out by brush once the wash was properly dry.
I have seen some fine examples of salt washes being used for textures in silk painting also, but have not yet experimented with this.