Watercolor Paint is a mixture of Gum Arabic and pigment, Artist quality watercolor contains nothing more. Watercolor is water soluble, meaning that it mixes and cleans up with water. Unlike Oil and Acrylic Paints that dry permanent, Watercolor is resoluble, meaning that once dry, if moistened, it can become fluid paint anew. Watercolor is designed to function on paper, though many newer substrates have become accessible. Watercolor dries relatively fast and was originally thought to be a sketching medium, though with the pigments, papers, and other substrates available it has become a permanent means of finished artwork.
The Basics: Watercolor