both the bright and dark sides; both sides of the coin
Used to describe the dual nature of something, encompassing both positive and negative aspects. Often appears in analytical or reflective contexts.
Advances in science and technology have both bright and dark sides.
He analyzed both the positive and negative aspects of the policy.
光と影 is a more poetic expression for 'light and shadow', often used metaphorically for the dual nature of something, similar to 明暗両面 but slightly more literary.
Compound of 明暗 (bright and dark) and 両面 (both sides). The exact historical derivation is uncertain, but the components clearly convey the meaning of two contrasting aspects.