Gauache. Gouache, body color, or opaque watercolor is a water-medium paint consisting of natural pigment, water, a binding agent, and sometimes additional inert material.
   Gouache is designed to be opaque. Gouache has a long history, having been used for at least twelve centuries.
   It is used most consistently by commercial artists for posters, illustrations, comics, and other design work. Gouache is similar to watercolor in that it can be rewetted and dried to a matte finish, and the paint can become infused into its paper support.
   It is similar to acrylic or oil paints in that it is normally used in an opaque painting style and it can form a superficial layer. Many manufacturers of watercolor paints also produce gouache, and the two can easily be used together.
   Gouache paint is similar to watercolor, but it is modified to make it opaque. Just as in watercolor, the binding agent has traditionally been gum arabic but since the late nineteenth century cheaper varieties use yellow dextrin. When the paint is sold as a paste, e.g. in tubes, the dextrin has usually been mixed with an equal volume of water. To improve the adhesive and hygroscopic qualities of the paint, as well as the flexibility of the rather brittle paint layer after drying, propylene glycol is often added. Gouache differs from watercolor in that the particles are typically larger, the ratio of pigment to binder is much highe
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