Practicals
Lamps, candles, signs, or screens visible in the shot, helping the scene feel lit from a believable place.
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What it is
Practicals are light sources visible inside the frame: a table lamp, candle, neon sign, television, phone screen, or bare warehouse tube. They explain where the scene's light appears to come from and give the background bright points, color, and depth. A hidden lamp doing the real work is still useful, but it is not itself a practical.
Reach for them when a room needs to feel inhabited or when motivated lighting matters. A bedside lamp can justify a warm key, a laptop can justify cool light on a face, and a row of street signs can break up a dark background. Stanley Kubrick shot the candlelit interiors of Barry Lyndon on Zeiss Planar 50mm f/0.7 lenses originally made for NASA, the famous anchor for a scene lit by what you can see in it.
Gotcha: the bulb is often far brighter than everything it is meant to illuminate. Expose for the face and the shade turns into a white hole; expose for the bulb and the room vanishes. Use a dimmer, a lower-output bulb, or diffusion inside the shade, then hide a controlled source nearby to carry the same direction and color onto the subject.
Ask AI for it
Build the frame around motivated lighting from practicals: keep one dimmed tungsten table lamp visible behind the subject and a laptop screen visible in front. Use the lamp to justify a 3200K warm edge and the screen to justify a restrained cool facial fill. Apply inverse-square law falloff across the room, retain texture in both lampshade and face, and avoid clipped white bulbs or unexplained studio light.