Watercolour
Transparent paint bound with gum, thinned with water and used on paper.
Also: aquarelle
Watercolour is pigment bound with gum arabic, a sap from acacia trees. It is thinned with water and applied in washes that let the white paper shine through. There is no white paint in the classic method; light areas are simply left bare, so the painter must plan ahead. It is portable and quick, which made it the medium of travelling artists, botanists and map makers. Because the paint film is so thin, watercolours are more easily faded by light than oils and are best kept out of direct sun.