Lighting Basics — Three-Point Lighting, Color Temperature and Natural Light

• Key light — The main light in the scene. It usually sits off to one side of the camera at an angle (about 30–45 degrees) and sets the direction of light and shadow on the face.
• Fill light — Softens the shadows from the side opposite the key. Keep it weaker than the key so the face keeps its shape. A reflector often does the job.
• Back light — Hits the head and shoulders from behind and above, separating the subject from the background. Also called a rim light or hair light.

Add a background light and you can control the subject and the background separately. Three-point lighting is a starting point, not a formula. If the scene has a plausible source of light, such as a window or a lamp (the motivation), matching your key to that direction looks natural.

The difference in brightness between the key side and the fill side of the face is the key-to-fill ratio. One stop of exposure means twice the light, so 2:1 is a one-stop difference, 4:1 is two stops and 8:1 is three stops.

The quality of light depends on how big the source is compared with the subject. A small source gives hard light with crisp shadow edges. A large source gives soft light with shadows that fade gradually. The same light gets relatively smaller, and harder, the farther away you put it.

• Hard light — Midday sun on a clear day, a bare fixture. Crisp shadows create tension and a strong impression.
• Soft light — An overcast sky, a big window, light through diffusion. Skin looks smoother and shadows look natural.
• Making it softer — Put diffusion (silk or a diffuser) in front of the light, or bounce it off a wall or reflector to make the source bigger.
• Distance and brightness — Light falls off with the square of the distance, so moving a light twice as far away leaves about a quarter of the brightness (the inverse square law).

The color of light is measured as color temperature in kelvin (K). Lower numbers are more orange, higher numbers more blue. Set the camera’s white balance to match the source and white comes out white.

When daylight from a window and tungsten light indoors share one frame, one side records blue and the other orange. Fix it with color gels in front of the lights. CTB shifts tungsten toward daylight, and CTO shifts daylight toward tungsten. LED lights with adjustable color temperature make this easier.

• Windows — A large window makes an excellent soft key. Seat the subject at an angle beside it and put a reflector on the other side to fill the shadows.
• Reflectors — White returns light softly, silver strongly, gold warmly. It is the easiest way to save a face in a backlit outdoor shot.
• Midday sun — With the sun overhead, shadows form under the eyes. Move into shade or rig a big silk overhead to spread the light.
• Golden hour — Just after sunrise and before sunset, when the sun is low and the light is warm and soft.
• Magic hour (blue hour) — The short window right after sunset when light is still in the sky. Crews sometimes use “magic hour” for golden hour as well.
• The moving sun — The sun never stops, so light direction can change between shots of the same scene. Check sunrise and sunset times and the sun’s path in advance and plan your shot order around them.

• Interior night — If the windows are bright, it won’t read as night. Black out the windows and use on-screen lights such as lamps and ceiling fixtures (practicals) as your motivation.
• Exterior night — Pick a motivation such as streetlights or signs, and light large areas softly from up high to suggest moonlight.
• Day for night — Shooting in daylight, then underexposing and grading blue so it looks like night. Keep bright sky out of frame and use backlight for a more natural result.

• Check the location’s electrical capacity (breakers) and spread the load so the total wattage stays under it
• No daisy-chained power strips; on big jobs use a generator and assign someone to handle power
• Run cables away from walkways and cover crossings with tape or mats so no one trips
• Put sandbags on stand legs and add safety cables to lights rigged up high
• Water and rain — never handle lights with wet hands; outdoors, use rain covers and ground-fault protection
• Lights get very hot; wear gloves and keep them away from fabric and paper