Other types of paint can be used with the impasto technique: you’ll find that acrylics lend themselves quite well to this technique, though not as well as oils. If you want to use watercolours for this technique, you’ll have to add some sort of thickening agent to them to make them suitable for impasto. Most impasto paintings are done with oils – even if you’re painting with oils, you can still add mediums to the paint to make it even thicker. As for brushes, you should use any brush that’s capable of holding a lot of paint. Similarly if you’re using a knife, use one that can easily hold lots of paint.
The impasto technique is quite easy to master. Simply load your brush or knife with much more paint than you’d normally need and apply it thickly to the canvas. Instead of spreading it out, you want to leave it in a lump of sorts – the whole idea of this technique is to have raised bits of paint. Use palette knives to help fashion the paint into the shape you want. Don’t worry about leaving marks from brushes or knives – again with impasto, you want rough texture and having marks from brushes or knives helps add to the feel of the painting.
Oils dry very slowly indeed. This can be problematic with impasto because you’ll find that thicker layers of paint can start to crack if they’re left to dry really slowly. The good thing to know is that this can be dealt with very easily. All you have to do is add a medium to the paint. You can get specialised impasto mediums that add to the paint’s thickness and speed up the paint’s drying time without having any negative effects on the paint or the painting.