These three elements of gouache technique are the keys to handling it well.
Consistency. Gouache paints from the tube are usually a bit thick and dry, so it's often necessary to add water in order to have good brush flow. But it's important—particularly when you mix with white—to keep the mixture thick enough to maintain the opacity and coverage necessary for the solid look and texture of an oil painting. Plus, when a gouache mixture is too thin or wet, the value will be darker than expected when it dries. The ideal consistency should be like melted ice cream, and it's worth experimenting to develop a feel for this.
Drying Time. The drying time for gouache paint is short and critical. Finding and maintaining the right consistency for a mixture (mentioned above) will prolong the drying period, however. Always mix more than you think you'll need, but when adding paint to your mixture as needed, don't forget to add water to keep the consistency in balance. Likewise, when you want to add water to improve the flow, add paint as well to prevent the mixture from losing opacity when it dries. Finally, it's difficult to rescue dry paint, so have a good spray bottle handy, watch your paint closely and spray a fine, even mist over the mixture if it's getting too dry.
Transitions. We perceive mostly soft edges, but because of the fast drying time and the opacity of gouache they can be difficult to create in this medium. Painting wet-into-wet usually helps, but for this you have to control the consistency and get the color just right—all within a brief window of time. When painting over dry layers, try mixing transition colors that relate in value and tone to each of the separate masses. Also, try using a stump brush (a short-haired bristle brush) dipped in fairly dry paint, then rub it from one area to the next. By controlling the pressure you apply, you can make the transition look somewhat faded or dense and solid. Or use a soft-haired brush with fairly dry paint to feather the edges—a good way to soften edges in any medium.
The value. For example, the color of the water surface relates to the color of the sky, which affects the color and value of a reflection.
Gouache is a great medium for handling these modifications. In the early stages of a painting, I like to establish the position of the reflection by painting the general shapes and making sure they line up vertically, and then I use drier, thicker paint to create the surface color and texture with horizontal movement. With the opacity of gouache, a lighter mixture can be painted directly over a dark one, whereas traditional watercolor would require great planning to save these light areas.
The color of a water surface in the distance will reflect the sky color near the horizon line, and the contrast in this area is typically weaker both in value and color than elsewhere in the painting. This effect can be difficult to achieve, as the strokes are often so close together at the horizon that they disappear altogether and the pattern of the reflection, which may be dramatic in the foreground, diminishes and breaks up. This is where the advantages of gouache shine through, however, for going back and forth many times from light to dark is much easier if light can be applied directly over the dark. Plus, because gouache dries quickly, you have the option of painting either wet or dry, and with fairly dry paint, you can rub or scratch into it to create subtle transitions.
The Secret to Success
Gouache is an old medium, in use since the time of Dürer 500 years ago, and it has many appealing features for the artist: low cost; solid, bright colors compared to watercolor; and an attractive matte surface compared to acrylic. As a water-based paint, it creates less mess and odor than oil, and its short drying period permits fast, direct painting techniques.
Today, although gouache is common in the design field and used all over the world, it's somewhat rare in fine art. I think of it as a well-kept secret, but one that more artists should be made aware of. For I've found gouache—with its strong colors, versatility in technique and convenient drying time and cleanup—to be the ideal way to combine the rich look of an oil painting with the ease of watermedia. With that combination, there's no limit to what you can paint.
About the Artist
Born and raised in the People's Republic of China, XIAOGANG ZHU received some formal academic training in art after completing military service. He became a textile and graphic designer, and then an art professor at a vocational school in Nan Jing and a university in Shanghai before moving to the United States in 1989. He received a master's degree in painting from Radford University in Virginia in 1991, He's now a signature member of the American Watercolor Society; his work is exhibited in several prestigious galleries; and he's won numerous awards in international art competitions, including the High Winds Medal from the AWS in 1995 and first prize in the landscape category of The Artist's Magazine's 1999 Art Competition. He lives with his wife and two sons in Shelton, Washington.
On the Move
With the boat passing through Sunday Morning, China (gouache, 14x20), the water is in motion as well, breaking up the reflections To capture these scattered, horizontal colors I repeatedly switched between the lights and the darks-that's gouache's specialty.
Sunday Morning, China (gouache, 14x20)
The In-between
Compare Morning Creek, China (gouache, 20x14) with Sunday Morning, China and Calm Bay View (on the previous pages) and see that the water here is neither calm nor fully in motion. Therefore the vertical reflection of the tree is clear, but not very sharp.
Morning Creek, China (gouache, 20x14)
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