Most people have never heard of a centuries-old type of paint called gouache. I'm here to tell you why it's so magical and how to use it to create vibrant, luminous works of art.
But first, a pronunciation lesson. Say it with me now: "Gwosh" (in your Frenchiest accent, please).
Gouache is similar to watercolor and tempera paint. It's made up of a high ratio of color pigment and a solid white pigment such as chalk, plus gum arabic as a binding agent. When I was in art school, a teacher referred to gouache as "watercolor, plus chalk." That does oversimplify things a bit, but it gets the basic point across.
Gouache has a lovely, heavy, velvety texture that absorbs light rather than reflecting it, creating a very smooth appearance. This makes it ideal for opaque coverage. In fact, gouache is sometimes referred to as "opaque watercolor."
Gouache vs. watercolor vs. acrylic
Like watercolor, gouache is sold in small, very concentrated portions. Each is commonly diluted with water before you paint with it, but gouache will be far less translucent than watercolor when diluted with the same amount of liquid.
Another difference: Gouache has more pigment than watercolor, so its texture is not quite as delicate. This makes it a good choice for some types of canvas or coated surfaces.
Like acrylic paint, gouache is opaque in its natural state. Keep in mind that it dries darker than the value painted on the paper or work surface, so matching mixed colors after the paint is dry can be tricky.
How to paint with gouache
Mix the right consistency
Typically, you don't want to use gouache right out of the tube. A little water goes a long way. Think of melted mayonnaise — even though that might be a gross concept, that's the consistency you're after!
If you have trouble getting the water level just right, use a spray bottle to mist on a little at a time instead of dipping your brush over and over.
Apply as a wash
When you dilute gouache with water, you can apply it as a wash that will dry opaque.
Warning: Because gouache is water-soluble and water-permeable, when you paint over the background layer, you run the risk of bringing up pigment from previous layers, which can muddy your colors in ways you didn't anticipate. To reduce this, make sure your background layer is completely dry, and be thoughtful as you layer over with a wet mixture.
Create detailed line work
One benefit of gouache is that you can layer opaque painted lines over opaque backgrounds. (Again, be sure to let your background wash dry completely first.) This gives you nearly endless possibilities for creating detailed compositions.
Contrast is key for really letting the line work show through. Think light and dark, cool and warm, and complementary colors.
Gouache is typically smooth in texture, but if you're going for a rougher look, scumbling can be a great technique.
Use a large, flat, dry brush — no water! — loaded with only a bit of paint. When you pull the brush over the surface, you'll notice some gaps in the stroke, which lets the background color through and creates a different texture.
Care for your canvases and brushes
Because gouache is a fairly wet paint, you need a sturdy surface that won't buckle and ripple when it gets wet. Choose a canvas board or stretched canvas rather than painting paper. And it's always a good idea to prime your surface before you get painting.
Obviously keeping brushes clean is key, and cleaning gouache is easy! Simply rinse brushes, palettes and other materials with water.