Painting medium in which ground pigment (colour) is bound with oil, usually linseed. It has the advantage of being slow to dry and therefore reworkable. Oil paint can be applied with a brush or a palette knife to a prepared ground, usually stretched canvas. Oil paint was used for decorating houses as early as the 5th century, but its artistic application was gradually adopted and refined by artists such as the 15th-century Flemish painter Jan van Eyck. Passing from Flanders to Italy, oil paint quickly overtook tempera as the standard medium because of its flexibility and luminosity. Since the 16th century oil paint has been considered first among painting media, although acrylic paint may prove to be a rival because of its quick drying time. Techniques of the old masters One of the most elaborate techniques using oil paints, favoured by the old masters, employed the building up of colours in layers from dark to lighter tones. The paint was applied in a way that allowed the lower layers…