The technique of blocking some parts of a photograph to emphasize (or draw attention to) another part of the same photograph is called

Suppose that you are in a room with 3 doors and a crack in the ceiling for light. that is all. the doors each have a sign on them that says what there is behind them. door #1. a pool of corrosive acid. door #2. a crocodile that hasn't eaten in 8 months. door #3. a solar "oven". a giant lens that focuses all the sunlight at the entrance of the door. you must choose a door, which door do you choose?

Examine the piece above. what is the subject matter in this piece? what is the content?

This painting is by james whistler, and is entitled, symphony in blue and pink. what is the subject matter of this piece?