Now, the receiving board is tilted. With more tilt, fewer units strike. This means that as form turns from the light source, angled areas receive lower levels of light energy. A lamp will illuminate most strongly on a surface closest to it. The level of illumination will drop off as the distance from the light source increases.
Some lamps direct the flow of light so that there is a concentrated center to the beam.
Away from the center, light energy decreases. Weak illumination from above, striking generally vertical subject Light energy drops with distance away from a weak source. This means that a top lit vertical subject will appear to darken downward. The Color of Light Changes as Energy Levels Change. Yes, it's true.