Watermedia What’s What

Stephen Quiller uses four kinds of watermedia in the field and in the studio: acrylic, watercolor, gouache, and casein. Here, he breaks down the unique qualities of each.

WATERCOLOR

• is easily transportable when hiking a good distance to paint
• has a gum arabic binder
• is soluble when dry so the paint can be lifted
• dries lighter than when it’s first put on.
• Sedimentary granulation (as seen in the detail) can give beautiful effects.
• Cleanup is easy.
• Paintings need to be displayed with glass.

GOUACHE

• uses the same gum arabic binder as watercolor
• has a white precipitated chalk added to the pigment to give it body or opacity
• is soluble when dry and has a chalky matte visual quality
• can be used transparent, translucent, and opaque
• is ideal for small studies but not for large paintings
• should be painted on a rigid paper support such as 300-lb. watercolor paper or watercolor board
• works well in combination with watercolor.
• Quiller uses with watercolor when hiking distances.
• Paintings need to be displayed with glass.

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ACRYLIC

• has a poly-resin (plastic) binder and “the most brilliant color of all the watermedia”
• is ideal for subjects with intense color and for working in layers
• can be applied transparent, translucent, and opaque
• can be used on any non-oily support
• is insoluble once dry so beautiful transparent glazes can be applied one over another.
• Edges must be softened before drawing when working transparent.
• Quiller uses older brushes and makes sure to clean them well.
• Cleanup is more difficult.
• He uses when working close to his studio or his car.
• Paintings can be shown without glass.

CASEIN

• is a milk-based paint, which uses the protein of the curd for the binder, giving it “a beautiful, velvety-matte visual quality”
• should be used on a fairly rigid, non-oily support; when working thickly, 300-lb. watercolor paper, watercolor board, Aquabord, or wood panels are recommended.
• When first applied, the paint is semi-soluble and edges can be softened, but overpainting is still easy.
• Within about two weeks time, the paint cures and becomes insoluble.
• As with acrylic, Quiller uses older brushes and takes care to clean them well after use.
• Work can be displayed without glass.
• Cleanup is a little more difficult.