Here are some good illustrations of short and broad portrait lighting. This young man will appear in the Ojai Art Center Theater’s production of Never Too Late. We asked him to look “hapless.”
Short lighting. Here, most of Tyler's face is in shadow - the "shorter" portion of his face gets the key light. Short light improves dimensionality, thinning the subject.
Conversely, broad light refers to a key light covering the broader portion of face. Note that although the quality of light is nice and Tyler's expression is comparable to the image above, he looks a little chunkier and this picture lacks some of the punch and immediacy of the one above.