Acrylic Slow Drying Medium is useful when you need to keep your acrylic paint responsive for longer and therefore want to slow the drying time. This video demonstrates the impact of the medium versus water. An area of Acrylic Ultramarine Blue is mixed with water and cross shapes are scratched through the surface with a palette knife. Then, at one-minute intervals, a brush is dragged across the surface of a cross, one at a time, until the paint no longer responds. Then the same method is repeated but with Acrylic Slow Drying Medium mixed with the paint, rather than water. As is clearly shown, the paint with the medium remains workable for three times longer that the paint with water.