1. The earliest known paintings that were done in oils date back to the 7th century BC. These paintings were Buddhist words that were discovered in caves in Western Afghanistan. Oil paint did not become widespread for use in art works until the 15th century, when it became popular through Europe. Jan van Eyck, a 15th century Flemish painter, is widely believed to have invented it, though in reality he did not invent it, instead he developed it.
2. Oil paint is credited with revolutionizing art. One of its key properties is that it's very slow to dry. It gave artists a lot more time to work on their paintings and it allowed them to correct any mistakes they might have made. Oil paints allowed for artists' creativity to flourish more because artists could devote more time to each painting. Many of the most widely praised paintings were done in oils.
3. For a few centuries artists had to store their oil paints in animal bladders. This was because the paint tube was not invented until 1841. It was invented by John Goffe Rand, an American painter. Before the tube was invented, artists would have to mix their paintings themselves before painting. They would have to grind the pigment up themselves, then carefully mix in the binder and thinner.
4. The most basic type of oil paint is made up of ground-up pigment, a binder and a thinner, which is typically turpentine. For the binder there are lots of different substances that can be used, including linseed oil, walnut oil and poppy seed oil; each of these gives the paint different effects and has different drying times.
5. There are modern versions of oil paint that can dry a lot more quickly than the standard version. The way that it dries is not by evaporation, but by oxidation, the process where substances gain oxygen. It is generally accepted that the typical painting done in oils will be dry to touch after about two weeks, although it can take six months to a year before the painting's actually dry enough to be varnished.
6. Oil paint is very durable and tough, so it's used as a finish and protector. It can be used on wood and metal and in both cases, it can be used internally as well as externally. It's often applied to wood during construction and can be found on metallic surfaces on things like planes, bridges and ships.