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 to show through the upper layers to a certain extent. Transparent glazes were also added to give further gradations of tone. The old masters had to rely on extensive knowledge of the different chemical qualities of the paints because, if they were not carefully applied, the layers of paint could damage those around or next to them over a period of time.
Netherlandish technique Oil painting first developed in a distinct form in the Netherlands and Germanic lands during the 14th century, and with van Eyck attained a brilliance that led to the belief that he possessed some secret process. His method, and the Netherlandish method in general, was to paint transparently on a white gesso ground, the picture being smoothly finished piece by piece, with a luminous enamel-like result. The method was taken up in Italy, Antonello da Messina being a pioneer.
Renaissance techniques In Venice, Giovanni Bellini rivalled the brilliance of Flemish technique. A combination of a tempera underpainting with a final glaze of oil colour was a Renaissance technique used by Michelangelo. In the 16th and 17th centuries there was a further development of technique, and a desire to obtain greater depth and three-dimensional effect. The transparent method, still in essence that of the tempera painter, was replaced by a more elaborate process. The picture was first painted in monochrome, and on this basis the light parts were painted with thick opaque colour, the shadows being painted thinly. Successive glazes of transparent colour gave richness. The new phase of oil painting flourished in Venice, and Titian represents its perfection. Rembrandt, Rubens, and Velázquez give individual variants of what may be called the classic method.
Modern techniques A decisive change came with the 19th century, when painters such as the Impressionists abandoned the old-master process of building up a picture in stages, in favour of a direct mode of painting. In part this was due to the practice of painting from nature, which made swiftness of achievement necessary.
Oil painting has remained particularly responsive to individual treatment. For instance, the later work of Paul Cézanne, with its application of transparent colour (almost like watercolour) to represent delicate modifications of light on the form of an object, can be contrasted with the heavily loaded paint of Vincent van Gogh, who used the medium with an emotional violence.
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