Chiaroscuro

mid 17th century: from Italian, from chiaro ‘clear, bright’ (from Latin clarus ) + oscuro ‘dark, obscure’ (from Latin obscurus ).

Chiaroscuro, in art, is the use of strong contrasts between light and dark, usually bold contrasts affecting a whole composition. It is also a technical term used by artists and art historians for the use of contrasts of light to achieve a sense of volume in modelling three-dimensional objects and figures. Wikipedia