Today’s Japanese: meian

明暗 [めいあん] – light and darkness; light and shade

Made up of the characters for bright and dark, 明暗 indicates a contrast.

Examples:
明暗差 [めいあんさ] contrast (i.e. TV or photos)
明暗 [めいあん] を区別 [くべつ] する – to distinguish between light and dark