Wikipedia defines chiaroscuro as Italian for light-dark, in art is the use of strong contrasts between light and dark, usually bold contrasts affecting a whole composition.
Painters who employed this technique included Caravaggio (1573-1656) and Rembrandt (1606-1669). In modern photographic portraiture, “Rembrandt Lighting” is still a common device to add drama.
In nature photography, I can employ the concept of chiaroscuro by being very attuned to areas of light and shadow and emphasizing that contrast by exposing for the highlights alone and letting the darks go black. In the image below I was dealing with backlighting and a translucent subject which gives additional drama to the piece. Having such large areas of negative space (black areas) requires me to be especially sensitive to composition and balance in the image.
Photography as an art form is like any other two-dimensional visual medium. Many of the attributes of a successful painting need to be considered in photography. I strive to make images that are dramatic or peaceful, complex or minimalist, colorful or monochromatic. Understanding the impact of visual experiences on the psyche and how to employ visual tools, are all part of the process and fun of being an artist.