Discover the Difference

Part A - Determine whether or not light conditions are controllable to minimize ambient light when needed
-Controlled light assures no substantial stray light is allowed to enter the room that would increase ambient light levels to a point where the projected image is affected.

Part B - Determine if uncontrolled light is directed at the screen causing the projected image to "washout".
An example is uncontrolled light from sources such as ceiling lights directed on to the surface of the screen.