Plein air painters usually favor hog’s bristle brushes. These are far less expensive than softer hairs like sable. They are the only brushes that spread thick paint smoothly and evenly, making for the freshest technique.
Bristle brushes tend to form a flag (a v-shaped split) at the end over time. However, if the brush is made properly, with good interlocking bristles, it will have a natural resistance to fraying. Because field painters often go long periods without being able to clean their brushes, this durability is important.
There are some good synthetic brushes on the market, but none of them are quite as stiff as a good natural bristle brush.
In the following exercises, I've tried to keep the amount of solvent the same (except with the fan brush).
Flat brushes make an immediate, energetic mark. They're excellent for fast, powerful surface work, long sweeping strokes, and blocking in shapes.
The great advantage of a filbert is the variety of brushstrokes you can get from one brush. This is great for single strokes that taper, such as in water reflections. Its rounded edges are good for blending. Set on its side, it makes nearly as good a line as a flat does.
The only ‘novelty’ brush I carry is a double filbert, or Egbert, above. It’s a lyrical brush that has a lot of expressive quality.
Many plein air painters also carry liners and riggers, which are useful in paintings that are built up smoothly. I don’t paint that way, so I seldom use them. Another brush that is good for detailed work is an angled brush. However, you can do almost any work you can envision with just the brushes I've shown you above.
Next week, I’ll talk about watercolor brushes.