I call them pen and ink sketches as they are all done on the fly without any prior composition. I really enjoy the creative process of starting with a tree here or a bush there and just drawing on the fly where the drawing and indeed the whole composition evolves with my thoughts and feelings at that moment. This gives these pen and ink sketches an organic feel that I think is lost when there is a heavy prior preparation and composition and inking thereafter. These are mostly 8.5 inch by 5.5 inch and done on Mixed Media paper with a fine gel pen or a fountain pen.
Learn to draw such landscapes with my fully illustrated and completely free tutorials. You can do them too if you try.
