A tube of yellow artist's oil paint. Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnish may be added to increase the glossiness of the dried film. Oil paints have been used in England since the 13th century for simple decoration, but were not widely adopted as an artistic medium until the 15th century.