Oil colours medium. Perfect substitute for universal medium. This medium will enable you to improve the consistency of your paste, to create glazes and the other effects such as impasto. This product is invaluable if working in cold temperatures. This medium also speeds uz drying time and adds a shine to your paintings. Green For Oil is part of the "bio-solvent" family, a safer, greener alternative to traditional solvents. A range offering the same properties as traditional additives. Biosolvents are sourced from renewable raw materials, with a focus on biomass-based sources. They are products of natural origin: derived from plant-, animal- or mineral-based raw materials. They respect sanitary and environmental standards, as they have been created with sustainable development in mind. Their main features are the same as those of traditional solvents. The end product is just as effective.