Oil is the paint of all paints, and the preferred medium of most modern masters. It is an amazing medium for several reasons. First, the dry-time makes painting more relaxing and more of an exploration. You can mix paints on your palette, that are good for several days which allows for less wasted paint and the ability to have a second sitting if you need it. On the canvas as well, you have time to apply paint and blend later, or even blend colours directly on your surface. Either way it provides for a nice, loose painterly effect. Secondly, the ability to thin out or go thick impasto makes for a powerful choice. Using some thicker paint in spots can literally add a third dimension to your work. All of these benefits apply as well to water mixable oil paints...same great smell but less chemical brain damage!
