Compared to oil and watercolor, acrylic painting is a relatively modern medium for artistic expression. Since its invention in the mid-20th century, acrylic paint has provided artists with an alternative to toxic, pricey, slow-drying oil paints. They are water-based, quick-drying, not reliant on any toxic solvents and can be applied to a wide range of surfaces. When dry, acrylics are lightfast and permanent, and the surface becomes strong and flexible.