When and where to use it.
Low-key lighting is often used for more serious, dramatic, or narrative videos. With its moody, dark tones, “low-key lighting is effective for drawing attention to serious subject matter, or the darker, emotional side to the story,” notes Waltz. Low-key lighting translates well into black and white and is also popular in portrait photography. Film noir, or stylized Hollywood crime dramas, classically used low-key lighting. Due to its serious mood and high contrast, you’re less likely to see low-key lighting used in marketing or promotional materials.
How to achieve low-key effects.
For low-key lighting, you need to limit the ambient light in your scene and closely control your light source. Since white or light-colored walls reflect light easily, low-key lighting is most effective when shot against dark backgrounds. You can also use strategically placed black fabric to reduce light and control what’s bouncing around. You can shoot low-key images and videos with natural light, but it requires you to control the set or environment more strictly.