He drew diagrams of how shadows would vary in placement depending on the time of day, and how the color of the shadow would vary from the source of light and where the shadow was cast (Fiorani, 273). He relied on the works of Ibn Alhazen for his notes on the geometry involved in the rays of the sun, as well as on the connection between shadows and the atmosphere, although he may have also used the work of Biagio Pelcani (Fiorani, 275-276).
In painting these