Oil paint

Common modern applications of oil paint are in finishing and protection of wood in buildings and exposed metal structures such as ships and bridges.

Well-known Dutch-American artist Willem de Kooning is known for saying "Flesh is the reason oil paint was invented".

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.

Additionally, when yellow pigment was added to oil, it could be spread over tin foil as a less expensive alternative to gold leaf.

Oil paint was mainly used as it is today in house decoration, as a tough waterproof cover for exposed woodwork, especially outdoors.

The Flemish-trained or influenced Antonello da Messina, whom Vasari wrongly credited with the introduction of oil paint to Italy,[5] does seem to have improved the formula by adding litharge, or lead (II) oxide.

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.

Artists, or their assistants, previously ground each pigment by hand, carefully mixing the binding oil in the proper proportions.

Earlier media such as egg tempera dried quickly, which prevented the artist from making changes or corrections.

Oil paints blend well with each other, making subtle variations of color possible as well as creating many details of light and shadow.

By hand, the process involves first mixing the paint pigment with the linseed oil to a crumbly mass on a glass or marble slab.

Natural pigments have the advantage of being well understood through centuries of use, but synthetics have greatly increased the spectrum of available colors, and many have a high level of lightfastness.

When oil paint was first introduced in the arts, basically the same limited range of available pigments were used that had already been applied in tempera: yellow ochre, umber, lead-tin-yellow, vermilion, kermes, azurite, ultramarine, verdigris, lamp black and lead white.

The painter bought them from specialized traders, "color men", and let his apprentices grind them with oil in his studio to obtain paint of the desired viscosity.

In the twentieth century, mass production started of titanium white and a new range of lightfast synthetic organic pigments, such as arylide yellow, phthalocyanine and quinacridone.

Though having mainly an industrial application, these pigments by the twenty-first century had largely replaced traditional types in artistic oil paint also.

Some of the most poisonous pigments, such as Paris green (copper(II) acetoarsenite) and orpiment (arsenic sulfide), have fallen from use.