<P> Early Christian monks maintained these records and used the techniques in their own artworks . Theophilus Presbyter, a 12th - century German monk, recommended linseed oil but advocated against the use of olive oil due to its long drying time . Oil paint was mainly used as it is today in house decoration, as a tough waterproof cover for exposed woodwork, especially outdoors . </P> <P> In the 13th century, oil was used to detail tempera paintings . In the 14th century, Cennino Cennini described a painting technique utilizing tempera painting covered by light layers of oil . The slow - drying properties of organic oils were commonly known to early painters . However, the difficulty in acquiring and working the materials meant that they were rarely used (and indeed the slow drying was seen as a disadvantage). </P> <P> As public preference for naturalism increased, the quick - drying tempera paints became insufficient to achieve the very detailed and precise effects that oil could achieve . The Early Netherlandish painting of the 15th century saw the rise of the panel painting purely in oils, or oil painting, or works combining tempera and oil painting, and by the 16th century easel painting in pure oils had become the norm, using much the same techniques and materials found today . The claim by Vasari that Jan van Eyck "invented" oil painting is not correct but has cast a long shadow, but van Eyck's use of oil paint achieved novel results in terms of precise detail and mixing colours wet - on - wet with a skill hardly equalled since . Van Eyck's mixture may have consisted of piled glass, calcined bones, and mineral pigments boiled in linseed oil until they reached a viscous state--or he may have simply used sun - thickened oils (slightly oxidized by Sun exposure). He left no written documentation . </P> <P> The Flemish - trained or influenced Antonello da Messina, who Vasari wrongly credited with the introduction of oil paint to Italy, does seem to have improved the formula by adding litharge, or lead (II) oxide . The new mixture had a honey - like consistency and better drying properties (drying evenly without cracking). This mixture was known as oglio cotto--"cooked oil ." Leonardo da Vinci later improved these techniques by cooking the mixture at a very low temperature and adding 5 to 10% beeswax, which prevented darkening of the paint . Giorgione, Titian, and Tintoretto each may have altered this recipe for their own purposes . </P>

Who is credited with the reinvention and popularization of oil paints