A wonderful article about the hard effort that goes into making the art of Barsoom:

When an artist is learning to draw or paint there are certain subjects at which they all must try their hand. A landscape. Flowers. Animals. Children. With varying degrees of success, the artist has to have at least tried to depict certain types of scenes from low lighting, moody, introspective pieces to high energy, action scenes. The artist has to experience what it is like to capture these elements on paper or canvas.

Read the full article at Amazing Stories