Watercolor Vs. Gouache

Everybody has a pretty good idea of what watercolor is, but when it comes to gouache, things get a little hazy. When asked to explain the difference, most artists just say watercolor is transparent, and gouache is opaque. That’s generally true, but some watercolors are also opaque, like Chinese white and Naples yellow, while many dark colors in gouache tend to be quite transparent. The fundamental difference between watercolor and gouache is in the way they are used.

The traditional approach to watercolor uses the paper as the source of white in a painting, with color applied in thin veils. Some purists take this principle very seriously, even avoiding white paint altogether. Watercolor paint is used thinly and the sparkling paper underneath is an integral part of the painting. This technique allows artists to achieve great intensity and depth of color, while using a minimal amount of paint. The rough texture of watercolor paper enhances this effect, while breaking up surface tension and preventing paint from pooling and running excessively.

Image (right): "Boats at Saintes-Marie Watercolor" Watercolor, Vincent van Gogh, 1888

Once primarily for illustrators and designers, gouache has earned its place next to watercolor as a medium for fine art. Artists who work with gouache mix white paint directly with colors, usually from thin to thick. Because gouache quickly re-activates with water, layers tend to intermix, and darker colors will show through lighter ones. Some use this to their advantage, deliberately planning for lines to show through top layers. Others begin with lighter colors and work their way toward darks to prevent bleed-through. There’s also an acrylic-based version of gouache that doesn’t mix between layers, which can even be used on canvas.

Image (left): Cover of the magazine Voici la Mode, Gouache and black ink, Léon Bénigni ca. 1930

Because their ingredients and formulations are so similar, watercolor can be used with white paint like gouache, gouache can be used just thinly like watercolor, and they can be intermixed. While there are purists, most artists use a hybrid approach, combining transparent and opaque applications and using either the white paper or white paint as needed, and incorporating thin watercolor washes with substantial opaque gouache passages. Both types of paint are perfect as a travel medium, and for artists working in a small space. Combining them gives you a range of colors and effects that lets you make impressive works of art using a water media kit that can go just about anywhere!

Image (right): "An Algerian Man and Boy looking across the Bay of Algiers" Anders Zorn, Watercolor and Gouache, 1887