Chiaroscuro is Italian, literally meaning light/dark. The term comes from the art world (usually painting), and is used to describe very directional, contrasty lighting. As a medium based on light, photography is most appropriate to illustrate the concept. Besides, I just like saying the word.
The use of light and shadow could be considered the definition of photography (it is, after all, from the Greek, meaning light drawing). Dramatically lit portraits have a strength to them; in black and white – where there is only luminosity – it is only this play of light against dark which holds the image together.
This portrait is from a single light source:
Off-the-shoulder portraits are a favorite of mine, where clothing doesn’t conflict for attention with the subject. This is evident by the preponderance of these images in my portfolio. There is no question where the focus of the image is.
These images also tend to be black and white. That’s also no coincidence.
Raking light as used here, though, has to be used with care. It can exaggerate skin texture. Yet that risk is offset by the play of light and shadow, emphasized with the black and white processing of the image. The beauty of the subject is enhanced. And the more dramatic, at least in my eye, the greater the emphasis.
There is also subtlety in shades of gray. Like life itself.