Some painters soon adopted photography as a tool to help them record a model's pose, a landscape scene or other elements to include in their art. It is known that many of the great 19th-century painters, including Delacroix, Courbet, Manet, Degas, Cézanne, and Gauguin, took photographs themselves, used photographs by others and incorporated images from photographs into their work. While heated debates about the relationship between photography and art continued in print and in lecture halls, the distinction between a photographic image and a painting became more and more difficult to discern. As photography continued to develop, the interactions between painting and photography became increasingly reciprocal. More than a few pictorial photographers, including Alvin Langdon Coburn, Edward Steichen, Gertrude Käsebier, Oscar Gustave Rejlander, and Sarah Choate Sears, were originally trained as painters or took up painting in addition to their photographic skills.