Watercolor paint consists of fine pigment particles suspended in a water-soluble binder. The binder used for watercolor consists of glycerin, glucose, gum and wetting agents. Usually applied on paper, watercolor is semi-transparent, the white of the paper gives a natural luminosity to the washes of color. White areas of the image often are left unpainted to expose the paper.
Watercolors are sold as dried patches of dry paint or as liquid in tubes, to which water is added. The paint can be applied in various techniques such as wet-on-wet and wet-on-dry to achieve different effects.