Watercolor - 11x15
Only a few real supplies are needed for a watercolor painting but by far the most important is the type of paper that you use. Using GOOD watercolor paper will make all the difference in learning and enjoying the medium.
The gold standard for watercolor papers is Arches which is sold in different weights and finishes. To start I recommend 140 lb cold press that comes in large sheets measuring 22c30 inches. You can tear or cut them in to smaller shapes and paint on the front and back. Students often balk at spending the money for good paper but I tell them that using other brands or quality of watercolor paper will only frustrate them and hinder their creative progress!