Watercolour

Also spelled  Watercolor,  pigment ground in gum, usually gum arabic, and applied with brush and water to a painting surface, usually paper; the term also denotes a work of art executed in this medium. The pigment is ordinarily transparent but can be made opaque by mixing with a whiting and in this form is known as body colour, or gouache (q.v.); it can also be mixed with casein, a phosphoprotein of