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
World oil market chronology from 2003 two major oil suppliers reducing supply generated fears of a repeat of the 1973 oil crisis. The mid-July decision of Saudi Arabia to increase oil output caused little significant influence on prices. According to the oil minister of the Islamic Republic of Iran, Gholam-Hossein Nozari, the world markets were saturated and a Saudi promise of increased production would not lower prices. Several Asian refineries were refusing Saudi petroleum in late June because they were over priced grade. On July 3, "the Brent North Sea crude contract for August delivery rose to $US145.01 a barrel" in Asian trade. London Brent crude