In film school we were taught that the fill light determines the density of the shadows. What we weren’t taught was how important shadows are, and that while the “key” light certainly has directionality, the fill light can as well. Where shadows fall is just as important as how bright they are, which means that we need to look at not just intensity (which I’m not really going to cover here; that’s determined by your own taste) but at placement as well.

Here’s a typical three-point lighting setup. This is both a great learning tool and an awful formula to follow, because while most lighting breaks down into this in one way or another it is severely limiting if this is all you know how to do. Still, it’s a good starting point.





The reason the fill light is at the same height as the key probably stems from early studio cinematography when much of the lighting was placed high in a grid. Beauty lighting was often done from the floor (more on that later) but live television and grand feature film sets were almost always lit from the air.

In this scenario the key light is placed so that the nose shadow falls along the “smile line,” the line between the corner of the base of the nose and the edge of the mouth. The position of that light can make the nose shadow long (connecting to the cheek shadow for classical Rembrandt lighting) for “masculine” lighting or short when lighting for glamor. The fill light was set up opposite the key simply to fill in the shadows left by the key.

In the diagram above, where the key and fill light are the same size but differing intensities, the fill light will cast just as hard a shadow as the key light. The fill light’s shadow will be less obvious because it is less bright but it will still be present. There may be a dark area under the chin where neither light reaches but that can occasionally be helpful in hiding what a friend of mine calls “the gobbler,” pertaining to loose skin that collects under the chins of mature leading ladies.


Read the rest at: http://provideocoalition.com/index.php/aadams/story/fill_light_the_underdog_of_lighting/P0/