White Balance

White Balance

noun | Camera & Optics

A camera setting that compensates for the colour temperature of the dominant light source in a scene, adjusting the sensor's colour channel gains so that objects that are physically white or neutral grey are rendered as white or neutral grey in the recorded image. Without white balance correction, images recorded under tungsten light appear amber-orange; images recorded under cool daylight appear blue. White balance removes this colour cast, calibrating the image to a neutral colour baseline.

Quick Reference

The Explanation: How & Why

Light sources do not all produce the same colour of light. A tungsten lamp produces light that is heavily weighted toward red and orange wavelengths -- we perceive this as warm, amber light. Midday sunlight is weighted toward the middle of the spectrum with more blue -- we perceive it as neutral white. An overcast sky produces even more blue. A candle is extremely warm, around 1800K. These differences are described using the Kelvin scale of colour temperature, which is a physical measure of the colour of light emitted by a heated black body at a given temperature.

The human visual system corrects for colour temperature automatically. A sheet of white paper looks white under tungsten light, under daylight, and under a fluorescent tube because the brain adjusts its colour perception to compensate. A camera sensor does not do this automatically -- it records the actual colour of the photons hitting each pixel. Without correction, the image reflects the true colour of the light source: warm under tungsten, cool under daylight.

White balance is the camera's equivalent of the brain's chromatic adaptation. By adjusting the relative gain of the red, green, and blue colour channels, the camera boosts the channels that the light source is deficient in and reduces the channels it is dominant in. Set to 3200K, the camera boosts blue relative to red, correcting for tungsten's warmth. Set to 5600K, it applies a more neutral gain ratio appropriate for daylight.

White balance can be set in several ways:

Preset values: Most cameras offer preset white balance positions -- 3200K (Tungsten/Indoor), 5600K (Daylight), 4000K-4500K (Fluorescent), 6500K (Cloudy). These are accurate for their intended light sources.

Kelvin dial: The camera allows direct entry of any Kelvin value, giving precise control for sources with specific known colour temperatures or for intentional creative colour shifts.

Custom white balance: The camera photographs a white or grey card in the scene's actual light and calculates the exact correction needed to render that card as neutral. This is the most accurate method for unknown or mixed light sources.

Auto white balance (AWB): The camera continuously analyses the image and adjusts the white balance in real time. AWB is appropriate for some documentary and event situations but is generally not used for narrative production because it changes between shots, making colour matching in the grade inconsistent.

Creative use of white balance involves intentional miscorrection. Setting the camera to 3200K in 5600K daylight renders the scene with a strong blue cast. Setting it to 5600K under 3200K tungsten renders the scene orange. Both can be deliberate aesthetic choices or can represent specific narrative colour moods. In the grade, the colorist works from the white balance set on camera, and deliberate white balance choices communicate specific creative intentions.

Historical Context & Origin

Colour temperature correction in film photography was managed through two main methods: using film stocks balanced for specific light sources (daylight-balanced or tungsten-balanced film), and placing physical correction filters over the lens or light sources. Tungsten-balanced film (Type B, balanced for 3200K) was the standard for interior studio production; daylight film (Type D, balanced for 5500K) was used for exterior work. Colour correction filters -- blue 80A/80B for converting tungsten to daylight balance, amber 85/85B for the reverse -- were placed over the lens when the ambient light did not match the film stock. The development of video cameras from the 1960s and their adoption in broadcast news and documentary production from the 1970s brought electronic white balance to production practice, allowing camera operators to set the colour balance for any light source in real time without changing physical filters.

How It's Used in Practice

Scenario 1 -- Mixed Light Interior (DP / Gaffer): A scene is lit with tungsten practical lamps (3200K) and supplemented with an HMI fresnel (5600K) as the key. The gaffer covers the HMI with full CTO gel, converting it to approximately 3200K. The DP sets the camera to 3200K. All light sources now balance to the same Kelvin value and the image is neutral at that balance point.

Scenario 2 -- Creative Colour (DP): For a scene set in a cold, institutional environment, the DP sets the camera to 3200K while shooting under 5600K cool daylight. The result is a strong blue cast over the entire image. Rather than correcting this in the grade, the DP and director agree that the cold blue is correct for the scene's emotional register. The white balance miscorrection is a deliberate aesthetic choice, not a technical error.

Scenario 3 -- Custom White Balance (DP): Shooting in an old theatre with a mix of sodium vapour stage lamps, fluorescent work lights, and some tungsten fixtures, the DP does not have a reliable Kelvin value for the combined sources. A grip holds a white foam board in the key light position. The DP uses the custom white balance function to photograph the board and let the camera calculate the exact correction. The image neutralises cleanly on the custom setting.

Usage Examples in Sentences

"Set the camera to 5600K for the exterior -- we are shooting in full daylight and want a neutral base."

"The blue cast is intentional -- the camera is set to 3200K under daylight and I want that cold look."

"Custom white balance the camera on that grey card in the key light before we roll the interview."

"Never use auto white balance for narrative production -- it will drift between shots and make the colorist's life impossible."

Common Confusions & Misuse

White Balance vs. Colour Grade: White balance is a camera setting established during production to neutralise the colour of the light source. Colour grading is the post-production process of adjusting the colour of the recorded image for creative and aesthetic purposes. A correctly white-balanced image may still be colour-graded heavily; a poorly white-balanced image gives the colorist less latitude and a less neutral starting point. White balance is the foundation; grading is the structure built on it.

White Balance Kelvin vs. Light Source Kelvin: The white balance Kelvin value set on the camera should match the Kelvin value of the dominant light source in the scene to produce a neutral image. If the camera is set to 5600K and the light source is 3200K, the image will appear warm because the camera is applying daylight correction to a tungsten source. The camera Kelvin and the scene Kelvin must match for neutral rendering. When they do not match deliberately, the result is a colour cast.

Variations by Context

Related Terms

• Colour Temperature -- The Kelvin scale on which white balance is calibrated
• Gel -- CTB and CTO correction gels shift light source colour temperature to match the camera's white balance setting
• Available Light -- White balance is the primary colour management tool when working with existing sources
• ISO -- A separate camera parameter from white balance; both affect the image but independently
• Exposure -- White balance does not affect exposure; it only adjusts colour channel ratios

See Also / Tools

The Exposure / Shutter / Focal Length Calculator handles the exposure parameters alongside which white balance decisions are made. Understanding the colour temperature of your scene's light sources before setting white balance is essential -- measure with a colour temperature meter or use known source values.