When To Face The Key Light
With the subject’s face turned toward the key light, that type of illumination is known as short lighting. The side of the face that’s away from the camera will be brightly illuminated, while the side of the face that’s more fully toward the camera will be more shadowed. This is a great technique for adding some interest or even a hint of mystery to a portrait, as the majority of the visible face is shadowed. (How light or dark this shadow is, of course, is a function of the fill light.) Short lighting does work well in scenes that are dark overall (or “low key”), especially if the shadow side of the face is allowed to largely blend into a dark background. But in any case, whether high key or low key in effect, the short lighting produces a shadow on the side of the face more prominently visible to the camera. Because less of the face is brightly illuminated, this lighting approach can have a thinning effect on someone with a round face shape. As such, it’s a popular default approach to point the subject toward the key.
When To Face Away From The Key Light
I frequently photograph subjects turned toward and away from the key light to see which looks better for a given subject, and it’s surprising how often these guidelines prove true. Sure enough, with the subject turned away from the key light, more of the illumination is falling on the side of the face that’s presented more prominently to the camera, and therefore it will have the visual impact of appearing wider or broader. Thus, the name for this lighting approach: broad lighting. On a subject with an already round face, broad lighting isn’t likely to be especially flattering. But on those who may benefit from the perceived increase in face width, broad lighting is a great place to start. I often find broad lighting less interesting because it can illuminate a whole lot of unnecessary real estate on the side of the head. This broad lighting approach tends to place flattering light on the subject’s clothing, however, when their torso is turned in the same direction as their face. This raking light enhances shape and texture on garments and can make for an interesting look depending. So, while it may be easy to assume it’s always best to point the subject toward the key light, in fact, it’s not always true. It depends on the effect you’re hoping to achieve with that light and whether you want a broad illumination or a thinning, mysterious effect.