Oil painting is the process of painting with oil paint, which is obtained by mixing pigments with oil as an adhesive and binder. The oil used in oil paints is produced from different materials and by different methods, the most common of which are flax-seed oil, poppy seed oil, walnut oil and safflower oil. The type of oil is selected according to its wide range of properties, such as the amount of yellowing time or drying of the oil. There are also noticeable differences in the brightness of the oils. An artist may use several different oils in a painting depending on the type of pigment and the desired effects of the oils.