Acrylic paint was invented earlier in the
20th century, but became commonly used in the
United States in the
1950s. It is a
synthethic substance composed of
acrylic resins and
pigment and, before the resins have dried, is
soluble in water. Acrylic paint dries in a matter of minutes (unless mixed with a special drying retardant), and after it dries it is essentially
plastic and is no longer water-soluble.
Unlike oil paint, which will darken as it dries and further with age, acrylic paint exhibits no color change over its lifetime. It may turn out to be longer-lasting and more durable than oils.
Like oil paint, acrylic paint is viscous, about the consistency of warm butter. It comes in tubes or in plastic squeeze bottles; this latter stuff is a bit more liquid. The thicker stuff can be applied as is to the painting surface (often canvas) for some nice texture effects, or can be thinned with water and applied as a transparent wash. Artists usually use a somewhat stiffer brush for acrylics than they would for watercolors.