Observing light on a form and translating it into paint on canvas. It's not just seeing. It's grasping the the visual world in a way that you can understand it well enough to describe it on a 2D surface. Finding how to manipulate both the observed form and the paint itself to give an explanation of what you see. The stuff you have to work with is paint, brushes, color, value, shape, edges, contrast. Those are physical things you manipulate. Raw information comes in through the eyes. It goes out through your hand, brush and paint onto the canvas. In between, in the mind and in the heart is where the stuff really happens.