This past term I took a 10-week class taught by Jeff Watts on portrait painting with gouache. Since this was my first attempt at painting, I limited my palette to black and white so I could focus on value, edge control, and general painting technique.
Gouache is an opaque, matte-finish, water-soluble medium which can be re-activated repeatedly with water. Because it is water-soluble, it is also very fragile, which might be considered a drawback. It can be applied with a bristle brush, pen, or airbrush, and can be used in combination with other mediums. Gouache dries darker. A good technique book is "Gouache for Illustration" by Rob Howard. I found a copy at the library.
In the basic technique, I laid in a rough outline with a 2B pencil on a toned ground, making sure to include some key landmarks. Then working from dark to light I added non-overlapping areas of value, aka tiles, to model the form. Finally, I defined edges by blending adjacent tiles to varying degrees with a damp brush. This piece was a great exercise in shape invention, value assignment, and edge control. It took me about 20 hours to complete.
A note on my subject: Isaiah Berlin was a leading 20th century philosopher. A brilliant mind with a face to match IMO. I used his portrait, shot by Richard Avedon, as the source material for this painting. On first impression, I thought he resembled an owl (good look for a philosopher) so I played that up by slightly exaggerating his facial twists and rhythms .
For artists working in the medium, check out Virtual Gouache Land, a very talented painter there. Also see Thomas Paquette's gouache works. His oils are equally stunning IMO.
Added note: I'll be publishing future posts once weekly, probably on Tuesdays.
Isaiah Berlin 2008, gouache on illustration board, 10 x 8.