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Video basics3 min read

LESSON 89

White balance for video

Set it once; video forgives less.

IN THIS LESSON

  1. What white balance does
  2. The numbers to know
  3. Why video differs from stills
  4. Practice: a reliable method

What white balance does

White balance adjusts the mix of red, green and blue so that something white in the scene, such as a sheet of paper, appears white in the picture rather than orange or blue. Light sources differ in colour, and that colour is described by colour temperature in kelvins: lower numbers are warmer and more orange, higher numbers are cooler and bluer. Cameras offer presets, an automatic mode, and a custom setting where you point the camera at a white or grey card and let it measure.

The numbers to know

Tungsten studio lamps are rated at 3200 kelvin, and tungsten-balanced film was made so that this light records as white. Daylight film was calibrated to about 5600 kelvin, and the general daylight range sits between about 5500 and 6500 kelvin. Shade, overcast sky and window light run bluer than direct sun, and early or late sun runs warmer because the atmosphere scatters blue light away. Many cameras also have a tint control for the green to magenta axis, which matters under some fluorescent and LED sources.

Why video differs from stills

A photographer shooting RAW can change white balance freely afterwards. Most video, even in good codecs, bakes the white balance into the recording, so a wrong setting can only be partly corrected, and the correction costs quality. Automatic white balance is also risky in video, because it can drift during a shot as people move or clouds pass, leaving a visible colour shift in the middle of a take. That shift is hard to grade out, because it changes over time rather than sitting still, and the editor has to key a correction that follows it frame by frame.

Practice: a reliable method

This is working practice. Switch off automatic white balance. Either dial in a kelvin value that matches your main light, or take a custom reading from a grey card held where the subject stands, lit by the key light. Use the same setting on every camera in a scene. If you shoot log or RAW, still set it properly, because the monitor and the dailies will look right and the editor will thank you. When light changes a lot during the day, take a fresh reading at each new set-up and say the value aloud on the slate or write it in the camera report.

Try it today

  1. 01Switch your camera's white balance from auto to manual.
  2. 02Film a white card under a household lamp at 3200 K and at 5600 K.
  3. 03Now take a custom reading from the card and film it again.
  4. 04Compare the three clips side by side.
  5. 05Make a habit of a grey-card shot at the start of every scene.