Detail from Vincent van Gogh's Self-Portrait With a Straw Hat and Artist's Smock

This detail from Van Gogh's Self-Portrait With a Straw Hat and Artist's Smock clearly shows how he used pure color with very defined, directional brush strokes. Think of it as a less extreme form of Pointillism. When you view the painting from close up, you see the individual brush strokes and colors; when you step back they blend visually. The 'trick' as a painter is to be familiar enough with your colors and tones for this to be effective.