What is this technique used for?
This technique is used to give paintings a rough texture and to create special colour effects. What the salt does is it absorbs the water in the paint and causes the pigment in the paint to spread out. What you're left with is a lighter area that provides a contrast with the darker paint you applied. Using this technique in a particular part of a painting can help give that prominence to make it stand out and grab the viewer's attention.
Can it be used with any type of paint?
The only type of paint this technique is suitable for is watercolour because of the fact that the salt absorbs the water; the salt wouldn't have any water to absorb if you were painting with acrylics or oils, so the technique won't work with acrylics or oils.
Can it be used with any type of salt?
You can use any type of salt for this technique. However different types of salt will produce different effects and some types will work better than others. For the best effects, it's suggested that you use coarse salt. The bigger the piece of salt, the more it's going to absorb. This technique will still work with fine salt, but the effect won't be as pronounced as when using coarse salt.
How do I do it?
Using this technique is very simple. First get your watercolour paints and your support and paint the area you'd like to add the salt to. Once you've finished painting, lightly sprinkle some salt over the area you want to be affected, though of course the paint has to still be wet, preferably shiny and quite damp. If the paint has dried, this technique won't work; if the paint's too wet and there are puddles of liquid everywhere, the salt will absorb all the paint and you won't get the same effects. Get rid of any puddles by gently using a paper towel. Once the salted area is completely dry, then you should gently brush away the granules of salt - don't leave the salt on the painting.
Is there a knack to it?
It may take you a few tries before you get this technique right because you have to know exactly how much salt to use to get your desired effects. If you use too little salt, you're not going to get as many effects; use too much and you could end up seeing too much of the colour absorbed. There is a knack to judging how much salt you should use - the wetness of the watercolour paint also makes a difference, so bear that in mind when experimenting with this technique. Try to use this technique in a room that isn't too warm or cold: if it's too warm, the paint can dry too quickly, not giving the salt enough time to be effective; it it's too cold, you could find yourself waiting for ages for the paint to dry.