Oil paint very slowly, darken, and crack, unlike mastic and wax (the latter of which was used in encaustic painting). Greek writers such as Aetius Amidenus recorded recipes involving the use of oils for drying, such as walnut, poppy, hempseed, pine nut, castor, and linseed. When thickened, the oils became resinous and could be used as varnish to seal and protect paintings from water. Additionally, when yellow pigment was added to oil, it could be spread over tin foil as a less expensive alternative to gold leaf. Early Christian monks maintained these records and used the techniques in their own artworks. Theophilus
Palm oil for biodiesels. Hydrodeoxygenated biodiesel is produced by direct hydrogenolysis of the fat into alkanes and propane. The world's largest palm oil biodiesel plant is the €550 million Finnish-operated Neste Oil biodiesel plant in Singapore, which opened in 2011 with a capacity of 800,000 tons per year and produces hydrodeoxygenated NEXBTL biodiesel from palm oil imported from Malaysia and Indonesia. Significant amounts of palm oil exports to Europe are converted to biodiesel (as of early 2018: Indonesia: 40%, Malaysia 30%).. In 2014, almost half of all the palm oil in Europe was burnt as car and truck fuel. As of 2018,