Low key lighting is a lighting style characterized by a high contrast ratio between lit and shadowed areas, with most of the scene in darkness and illumination concentrated on specific elements. Unlike high key lighting which aims for even, bright exposure across the frame, low key lighting intentionally leaves large portions of the image in deep shadow, creating dramatic, moody, and often mysterious or tense atmospheres.

In technical terms, low key lighting typically uses a single dominant light source, or a few carefully controlled sources, with minimal fill light to soften shadows. The result is deep blacks, rich shadow areas, and strong contrast between illuminated and unlit regions. The style is closely associated with film noir cinematography, horror and thriller genres, dramatic portraiture, and scenes intended to evoke suspense, intrigue, danger, or emotional weight. Rembrandt lighting, a portrait technique using a small triangle of light on the shadow side of the face, is a classic example of low key lighting applied to human subjects.

AI image and video generation models respond well to low key lighting descriptions in prompts. Phrases like "low key lighting," "dramatic shadows," "single light source with deep shadows," "noir lighting," or "high contrast chiaroscuro" communicate the desired visual style clearly, helping generate imagery with the characteristic dark, atmospheric quality of this lighting approach.