Feathering is a fine-tuned form of hatching using short strokes. The result is rather like scumbling -- it can give a vibrancy to a painting. Feathering will also work for optical mixing of color (like with pointillist paintings) where the eye mixes the colours together rather than blending them on the paper.
Tip: This method is especially good for giving the appearance of iridescence of fabric, feathers, and scales, or for creating atmospheric effects with light.
