where did painters perfect the technique of painting with an oil medium
Oil painting Most Renaissance sources, in particular Vasari, credited northern European painters of the 15th century, and Jan van Eyck in particular, with the "invention" of painting with oil media on wood panel supports ("support" is the technical term for the underlying backing of a painting). However, Theophilus (Roger of Helmarshausen?) clearly gives instructions for oil-based painting in his treatise, On Various Arts, written in 1125. At this period, it was probably used for painting sculptures, carvings and wood fittings, perhaps especially for outdoor use. However, early Netherlandish painting in the 15th century was the first to make oil the usual painting medium, and explore the use of layers and glazes, followed by the rest of Northern Europe, and only then Italy.