Harold Speed, The Practice and Science of Drawing
“ This is a stroke lightly and quickly painted, where the brush just grazes the surface of the canvas. The paint is put on in a manner that is very brilliant, and at the same time of a soft quality. If the brush is only moderately full, such touches will not have any hard edges, but be of a light, feathery nature. It is a most useful manner of putting on paint when freshness of colour is wanted, as it prevents one tone being churned up with another and losing its purity. And in the painting of hair, where the tones need to be kept very separate, and at the same time not hard, it is very useful. ”
