He theorized on this idea in his 1800 treatise Reflections and Advice to a Student on Painting, Particularly on Landscape, developing a concept of a "landscape portrait" in which the artist paints a landscape directly while looking upon it, taking care to capture its particular details.
He theorized about a "landscape portrait" in his 1800 treatise, which involves the artist painting a landscape directly while looking at it and paying attention to its specific details.