Front projection screens are used when both the projector and the viewer are on the same side of the screen. The projector (or other light source) beams light onto the projection screen, which is then reflected off the screen and back at the viewer. This is a very efficient layout since it doesn't require any space behind the projection screen. Most screens are lighter in color, either white or a very light grey, which gives off a bright even light off the screen, this does make them easily susceptible to being washed out by ambient light. This requires brighter projectors when used in conjunction with stage or room lighting. The other major draw back with front projection is that shadows can easily be cast by people and objects in front of the screen, requiring an area in front of the screen to be kept clear.