The rules of noir light
Noir uses low-key lighting: one hard source, minimal fill, so most of the frame lives in shadow and the lit areas carry all the information. Hard light (small source, no diffusion) draws razor shadow edges — the opposite of beauty lighting — and that severity is the mood. Faces are half-lit deliberately: what's hidden matters as much as what's shown.
The venetian blind is noir's signature prop because it turns light itself into a pattern — stripes across a desk, a wall, a face imply an off-screen window, a private office, someone watching. The preset bakes this vocabulary in so your subject inherits the genre instantly.
Prompting like a 1940s cinematographer
Give the frame noir furniture: cigarette smoke curling through a light beam, a fedora brim shadowing eyes, a rain-streaked window, a desk lamp as the only source, a doorway silhouette. Smoke and rain are especially valuable because they make the light itself visible as shafts and streaks.
Compose with imbalance — subjects off-center, looming foreground shapes, staircases and doorframes cutting diagonals. Noir frames are anxious on purpose. And resist the urge to add color words: the preset's monochrome is the point; describe tone and texture instead.
Modern jobs for an old style
Book covers and podcast art for crime and mystery titles are the obvious fit — noir is genre signaling with a century of training behind it. Photographers and art directors use it for dramatic personal branding, musician press kits, and editorial portraits that need gravity.
It also pairs with Nidhogg's relight tool in reverse: generate in noir for the drama, or take an existing flat portrait and relight it toward a single hard key to retrofit the mood.