油彩
Oil paint is made by mixing pigments of colors with an oil medium. Since the 19th century the different main colors are purchased in paint tubes pre-prepared before painting begins, further shades of color are usually obtained by mixing small quantities together as the painting process is underway. An artist's palette, traditionally a thin wood board held in the hand, is used for holding and mixing paints. Pigments may be any number of natural or synthetic substances with color, such as sulphides for yellow or cobalt salts for blue. Traditional pigments were based on minerals or plants, but many have proven unstable over long periods of time. Modern pigments often use synthetic chemicals. The pigment is mixed with oil, usually linseed, but other oils may be used. The various oils dry differently, which creates assorted effects.