Adding a wash of color to a simple scribble is the first step for budding artists—and this comprehensive series of exercises and studies shows how to exploit this technique. The Artstrips set out the methods in detail, while the demonstration studies, sketches, and finished compositions provide inspiring starting points from which would-be painters move forward on their path to discovering the delights of painting.
This book looks at the quality of line and different washes, comparing different media and styles to generate lines. Then looking at different media for the washes including watercolor, ink and acrylic.
It includes media that serve both purposes, such as watercolor pencils, non-waterproof inks and washes over pastel.
I didn't feel the book had a lot to offer, but it is a quick and easy read and has nice art. I think there are better books to learn about line quality from.