<P> Italian polymath Leonardo da Vinci (1452--1519), familiar with the work of Alhazen in Latin translation and after an extensive study of optics and human vision, wrote the oldest known clear description of the camera obscura in mirror writing in a notebook in 1502, later published in the collection Codex Atlanticus (translated from Latin): </P> <P> If the facade of a building, or a place, or a landscape is illuminated by the sun and a small hole is drilled in the wall of a room in a building facing this, which is not directly lighted by the sun, then all objects illuminated by the sun will send their images through this aperture and will appear, upside down, on the wall facing the hole . </P> <P> You will catch these pictures on a piece of white paper, which placed vertically in the room not far from that opening, and you will see all the above - mentioned objects on this paper in their natural shapes or colors, but they will appear smaller and upside down, on account of crossing of the rays at that aperture . If these pictures originate from a place which is illuminated by the sun, they will appear colored on the paper exactly as they are . The paper should be very thin and must be viewed from the back . </P> <P> These descriptions, however, would remain unknown until Venturi deciphered and published them in 1797 . Da Vinci also drew 270 diagrams of the camera obscura in his notebooks . </P>

Who used the camera obscura as a tracing tool