For this reason, we are only used to seeing "true" red in limited areas. When we see an object painted in a single shade of red, it looks wrong and somehow flattened. This is because where the object receives direct light, the red will take on the color cast of that light, and where it is in shadow, it will take on the color cast of the environment's ambient light. Furthermore as objects recede from the viewer the color is further altered by atmospheric perspective.