Oil paint

The earliest surviving examples of oil paint have been found in Asia from as early as the 7th century AD, in examples of Buddhist paintings in Afghanistan. Oil-based paints made their way to Europe by the 12th century and were used for simple decoration, mostly on wood. Common modern applications of oil paint are in finishing and protection of wood in buildings and exposed metal structures such as ships and bridges. Its hard-wearing properties and luminous colors make it desirable for both interior and exterior use on wood, metal and fabric. Due to its slow-drying properties, it has recently been used in paint-on-glass animation. The thickness of the coat has considerable bearing on the time required for drying: thin coats of oil paint dry relatively quickly.

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 oil paint film. The addition of oil or alkyd medium can also be used to modify the viscosity and drying time of oil paint.

History

The technical history of the introduction and development of oil paint, and the date of introduction of various additives (driers, thinners) is still — despite intense research since the mid-19th century - not well understood. Incorrect theories and information are common, especially in sources written before 1952. Until 1991 nothing was known about the organic aspect of cave paintings from the Paleolithic era. Many assumptions were made about the chemistry of the binders. Well-known Dutch-American artist Willem de Kooning is known for saying "Flesh is the reason oil paint was invented".

First recorded use

The oldest known oil paintings are Buddhist murals created c. 650 AD. The works are located in cave-like rooms carved from the cliffs of Afghanistan's Bamiyan Valley, "using walnut, poppy seed oils, Linseed oil and castor oil." In some regions, this technique is referred to as the drying oil technique.

Classical and medieval period

Though the ancient Mediterranean civilizations of Greece, Rome, and Egypt used vegetable oils, there is little evidence to indicate their use as media in painting. Indeed, linseed oil was not used as a medium because of its tendency to dry very slowly, darken, and crack, unlike mastic and wax (the latter of which was used in encaustic painting).

Greek writers such as Aetius Amidenus recorded recipes involving the use of oils for drying, such as walnut, poppy, hempseed, pine nut, castor, and linseed. When thickened, the oils became resinous and could be used as varnish to seal and protect paintings from water. Additionally, when yellow pigment was added to oil, it could be spread over tin foil as a less expensive alternative to gold leaf.

Christian monks were aware of these ancient books and used the techniques in their own artworks. Theophilus Presbyter, a 12th-century German monk, recommended linseed oil but advocated against the use of olive oil due to its long drying time. Oil paint was mainly used as it is today in house decoration, as a tough waterproof cover for exposed woodwork, especially outdoors.

In the 13th century, oil was used to detail tempera paintings. In the 14th century, Cennino Cennini described a painting technique utilizing tempera painting covered by light layers of oil. The slow-drying properties of organic oils were commonly known to early painters. However, the difficulty in acquiring and working the materials meant that they were rarely used (and indeed the slow drying was seen as a disadvantage).

Renaissance onwards

As the public preference for naturalism increased, the quick-drying tempera paints became insufficient to achieve the very detailed and precise effects that oil could achieve. The Early Netherlandish painting of the 15th century saw the rise of panel painting purely in oils, or oil painting, or works combining tempera and oil painting, and by the 16th-century easel painting in pure oils had become the norm. The claim by Vasari that Jan van Eyck "invented" oil painting is not correct, but van Eyck's use of oil paint achieved novel results in terms of precise detail and mixing colors wet-on-wet. Van Eyck's mixture may have consisted of piled glass, calcined bones, and mineral pigments boiled in linseed oil until they reached a viscous state—or he may have simply used sun-thickened oils (slightly oxidized by Sun exposure).

The Flemish-trained or influenced Antonello da Messina, whom Vasari wrongly credited with the introduction of oil paint to Italy, does seem to have improved the formula by adding litharge, or lead (II) oxide. The new mixture had a honey-like consistency and better drying properties (drying evenly without cracking). This mixture was known as oglio cotto—"cooked oil." Leonardo da Vinci later improved these techniques by cooking the mixture at a very low temperature and adding 5 to 10% beeswax, which prevented the darkening of the paint. Giorgione, Titian, and Tintoretto each may have altered this recipe for their own purposes.

Paint tube

The paint tube was invented in 1841 by the portrait painter John Goffe Rand, superseding pig bladders and glass syringes as the primary tool of paint transport. Artists, or their assistants, previously ground each pigment by hand, carefully mixing the binding oil in the proper proportions. Paints could now be produced in bulk and sold in tin tubes with a cap. The cap could be screwed back on and the paints preserved for future use, providing flexibility and efficiency to painting outdoors. The manufactured paints had a balanced consistency that the artist could thin with oil, turpentine, or other mediums.

Paint in tubes also changed the way some artists approached painting. The artist Pierre-Auguste Renoir said, "Without tubes of paint, there would have been no impressionism." For the impressionists, tubed paints offered an easily accessible variety of colors for their plein air palettes, motivating them to make spontaneous color choices.