Jean-Baptiste-Camille Corot (1796 - 1875) was the leading French painter of the Barbizon school. Unlike the Impressionists, Corot painted only sketches in the open air; he composed his finished paintings in the studio. Corot executed many etchings and pencil sketches. Some of the sketches used a system of visual symbols—circles representing areas of light and squares representing shadow. He also experimented with a hybrid of photography and engraving. Starting in the 1830s, Corot also painted decorative panels and walls in the homes of friends, aided by his students. As he declared for his own method to depict: "I noticed that everything that was done correctly on the first attempt was more true, and the forms more beautiful."