Watercolors made their mark in art history as far back as 30,000 BC when they were used in cave paintings. Today they are also the most convenient and approachable painting application for the beginning artist, though it cannot be said that they are the easiest to master. Watercolor paints are easy to apply – just add water and a bit of creativity. The only other items you need are brushes and paper. The pigments used in creating watercolors are similar to those used in oils and acrylics: some are natural and some are synthetic. These pigments are ground and mixed with a natural sap binder called gum Arabic. The most sophisticated watercolors also contain glycerin as a moisturizer. Watercolor paints are sold in grades created for both the student and the professional artist. Student paints offer an economical way to experiment with the media while artist quality paints are more expensive because they contain a higher concentration of better quality pigments.