The majority of the world's masterpieces of art have been created with oil paints. Basically, oils are pigments that are bound into a "drying oil" which is an oil that hardens when exposed to air. The most common oil used is linseed oil. Here are a few facts about oil paints.

1. Oil paints were first used between the 5^th & 9^th century to decorate shields and other objects in western Afghanistan.

2. The use of oil paints did not appear in Europe until the 15^th century. Prior to this, most artist used egg tempera.

3. Early in the 16^th century, artist started painting on canvas instead of wood. Canvas had the advantage of holding the pigments better, resisted cracking which is a common problem of wood and needed less preparation.

4. White paint was created with lead. It dried quickly and covered well but had the disadvantage of being poisonous. Zinc became the substitute for lead in white paint around 1845.  Checking the composition of the paint is one of the ways to date a painting.

5. Prior to the 19^th Century, an artist's studio looked like a laboratory. The artists had to grind the pigments, boil the oil and use exact formulas to create their oil paints. Apprentices were hired to help with this chore.

6. Ultramarine blue was made with ground lapis lazuli, which was very expensive. After mixing it with the oil is was often stored in a pig's bladder.  There was only one source for lapis during the 1600's and that was at a single location in an area that is in Afghanistan.

7. It was not until 1841 that oil paints were available in a metal tube, premixed and ready to use. This freed artists from this chore and made it more practical to paint outdoors. "Without paints in tubes," August Renoir stated, "there would have been no Cezanne, no Monet, no Sisley or Pissaro, nothing of what the journalists were later to call Impressionism."