<span>Caravaggio's chiaroscuro technique refers to the usage of strong contrasts such as light (chiar) and dark (oscuro) in the oil paintings made by the painters of the Baroque, and many later art movements. This is used to create various dramatic effects in paintings so as to either hide something, or enhance its presence even more. Hope this helps. Let me know if you need additional help!</span>
It's pronounced "ensemble" by the way. And, one way that a pianist would have a role would be by being in the background as an example and playing his part. He's going to play what he needs to play. The question does seem a little to vague, but truly, I would say simply, that the person who is playing it, just plays his part as they all make music sound good.