Surfing on internet I found a portrait of Leonardo da Vinci and the news about the painting.I report the news about the paint.
The new portrait of Leonardo da Vinci, which was painted between 1475 and 1480 and can be found in Washington, The National Gallery of Art, was wrongly attributed to the Italian painter Cariani ( 1547), because Cariani used the same kind of background for his portraits. Cariani probably knew this particular painting and was inspired by the great master, although his skill was not comparable to that of Leonardo da Vinci. The latter is in his self-portrait not only dressed like the people of that time (those who could afford it), we also know that he was very interested in the study of drapery in the 70s of the 15th century. So, in this portrait you see in the background not only a look out of the window, you also see a wall upon which a cloth is showing his great interest in the study of drapery. By the way, it probably was customary for the pupils of Andrea del Verrocchio to paint a self-portrait.