Mastered for the first time by the Flemish painter Jan Van Eyck in the 15th century, oil painting is a process consisting of mixing the pigments of the paint in the oil during the preparation. Until the 19th century, pigments were crushed with oil just before use. Each technique was specific to the artist, the oils differing between each recipe, their preparation also. So the linseed oil quickly replaced the flaxseed oil and the walnut oil. The oil painting allowed more precision and transparency, it was the most used technique until the appearance of industrial painting. Yet it remains the reference painting for the greatest painters like the Mona Lisa of Leonardo da Vinci or the paintings of Vincent Van Gogh.