Can someone explain the process of taking away light via a projection? In the photo illustrating the story, the map of San Francisco on the wall is presumably all projected. Certainly the shadow on the map, hard and with a source to the left, does not match the shadows from the plant leaves the are soft and lit above and to the right.
My question, then, is what creates the darkness that gives them the dark shadows in the projected area? I understand perceived values, but since the room appears to have some degree of natural light, I don’t see how the dark areas could be the base ambient level of light falling on the wall. As I understand things, projectors only add light, not take it away, so what am I missing? Am I still thinking 20th century?
