White balance
Telling the camera what color the light is, so whites come out white instead of orange indoors or blue in the shade.
See it
What it is
Light has a color even when your brain refuses to see it. Household bulbs are orange (around 2700K), midday sun is neutral (around 5500K), open shade is blue (7000K and up), old fluorescents lean green. White balance tells the camera which light it is standing in, so it can shift everything back until a white shirt reads white instead of amber or cyan.
Get it right at capture with a gray card or a Kelvin value, and everything downstream is easier. Shoot raw and you can reset it later for free; shoot JPEG and the cast is baked in, recoverable only with damage. The most common real-world mess is mixed lighting: warm lamps plus cool window light in one frame, where no single setting fixes both halves. The fix happens on set, with gels on the lamps or by turning one source off, not in software.
Gotcha: correct is not always right. Nailing neutral white balance at sunset deletes the sunset, since the whole point of golden hour is the warm cast. Treat auto white balance as a starting point, then decide on purpose: a deliberate warm skew reads cozy, a cool skew reads clinical and modern. Auto is also unstable across a video clip, drifting when someone in a red jacket walks through frame.
Ask AI for it
Neutralize the white balance in this image using a known white or neutral-gray surface in the frame as the reference. If the scene was lit by warm tungsten, set the temperature to roughly 2700K to 3200K, then adjust tint until whites and grays read truly neutral with no green or magenta left in them. Match the setting to the actual illuminant rather than defaulting to 5500K, which only suits daylight. Keep skin tones natural instead of pushing them pink or gray, and preserve the existing exposure and contrast; change color only.