How to Write AI VFX Prompts for Relighting a Scene

Scene relighting is the most narrative-useful effect in FXbuddy's toolkit. It lets you fix continuity problems between clips, establish time of day without a reshoot, and dramatically shift the emotional tone of footage long after production has wrapped. Here's how to prompt for it effectively.

Relighting prompts work best when you describe the desired end state rather than the changes. Instead of "make it darker," say "deep night exterior lighting — cool moonlight from above, no warm fill, deep shadows in the background." The AI generates the new lighting state from scratch rather than incrementally adjusting the original, so absolute descriptions work better than relative ones.

The most practical uses of AI relighting for editors: matching two angles that were shot at different times of day, rescuing run-and-gun footage that was shot in flat or unflattering natural light, and pre-visualising a lighting approach before a colour grade session.

What FXbuddy needs in a relighting prompt

• Target lighting condition: golden hour, night exterior, studio key, overcast flat fill, candlelit
• Key light direction: from camera left, from above, from behind, from the window at right
• Colour temperature: warm orange-gold, cool blue-white, neutral daylight, warm amber tungsten
• Shadow depth and direction: deep shadows, soft fill, no directional shadow, long shadows from left
• What to preserve: keep background unchanged, maintain subject skin tones, preserve foreground colour

5 example prompts you can copy

Common mistakes

• Relative instructions: "Make it darker" or "warmer" gives the AI a direction but no destination. Always describe the end state: "deep night" or "warm golden-hour" rather than "darker" or "warmer."
• No key direction: "Relight with golden-hour light" without specifying which side the sun is on produces a centred, directionless warmth that looks flat rather than cinematic.
• Trying to add a practical light that wasn't there: "Add a lamp on the desk" asks the AI to generate a light source and the object simultaneously, which is difficult. It's more reliable to describe the quality of light the lamp would produce: "warm tungsten key from camera right, as if from a desk lamp just out of frame."
• Asking for subtle changes on a single pass: "Very slightly warmer" is hard for the AI to target. Generate a more dramatic version, then blend it at low opacity on your timeline if you want a subtle effect.

Tips for better relighting results

• Name a reference mood or scene to prime the AI: "Blade Runner 2049 night exterior" or "Malick golden-hour field" or "prison interrogation overhead light" — these genre shorthand cues work well.
• For continuity matching, describe the lighting of the clip you're matching to as specifically as possible. Take a screenshot of that clip and describe what you see: key direction, colour temperature, shadow depth, ambient fill ratio.
• Combine relighting with sky replacement for exterior shots. Do sky first, then describe the relighting that would logically result from that sky's light.
• Relighting works best on medium shots. Wide shots with many depth layers and tight close-ups with complex specular highlights are more challenging for the AI. Medium shots strike the right balance of surface area and facial detail.
• If the AI over-changes the subject's skin tones, add "preserve natural skin tones" to your prompt. The AI will prioritise skin tone accuracy over dramatic light changes when this instruction is present.

Frequently asked questions

What lighting changes work best with AI relighting?

Scene-wide mood shifts work most consistently — moving from flat overcast to golden hour, from daylight to moody blue-night, from warm to cold. Changes that require fine placement of small, specific light sources are harder for the AI and may produce variable results.

Can I relight a clip to match another clip in my sequence?

Yes. Describe the lighting conditions of the clip you want to match: "relight to match a warm golden-hour exterior, key light from the right, soft fill from the left, cool shadow tone." The more specific your description of the target clip's light, the closer the match.

Does AI relighting affect the entire frame or just the subject?

By default, relighting affects the entire frame — subjects, background, and surfaces together. If you want targeted relighting on just the subject, describe it explicitly: "relight only the subject — warm key from camera left, no change to background lighting." The AI will attempt to confine the relighting to the described region.

How do I use relighting to create a day-for-night effect?

Pair a sky replacement prompt (to swap the sky to night) with a relighting prompt: "relight for a night exterior — remove warm daylight from all surfaces, replace with cool moonlight from above and left, add blue-silver ambient fill. deep shadows throughout." The combined approach produces convincing day-for-night on most exterior clips.

Related prompt guides

Also see the AI Scene Relighting effect page for a full workflow walkthrough.