Chiaruscuro
This is a tool used by artists to add drama to their work. It is where there is a huge contrast in the lights and darks in an image. This could be done with lighting, or simply by exaggerating the shadows in their subjects.
Here are some examples of artists who have used Chiaruscuro in their work (NB these artists may not have used Chiaruscuro in all of their work).
Stanley Spencer
Jack Vetrianno
Wayne Thiebaud
Andrew Wyeth