The primary technical difference between oil and acrylic paints is the liquid or substance in which the pigment is suspended. In accordance with the name, oil paints contain pigments suspended in oil, typically linseed. Acrylic paints, however, use polymer. Due to these contrasting elements, the most important practical difference between oils and acrylics is that the former takes a long time to dry, whereas the latter does so rapidly.
Because oils are slow-drying, they are often suggested for beginning art students. The added time allows the student to go in and fix mistakes or modify content. Additionally, oils are ideal for those who wish to extend painting time even further, as the paint is still workable at least a day after being applied to the canvas. Because of their signature viscosity, oil paints are also better for achieving smooth blends of color than are acrylics, a benefit further enhanced by the long drying time. However, acrylics also have substantial benefits. As opposed to oils - which demand a prepared surface such as canvas or board - acrylics can be used on any surface. Nontoxic acrylics are also typically cheaper than oil paints and do not require turpentine for cleaning. Whereas oils are better suited to blending, acrylics tend to offer sharper edges, a feature which may be compositionally important to the artist. Finally, the sharp pigment of acrylics do not fade, while oils tend to yellow over time due to oxidation.