Custom white balance is a camera setting in photography that derives the white balance correction from a reference image of a neutral target photographed under the light that illuminates the scene. Instead of guessing the light source or relying on a preset, the camera measures how the target departs from neutral and stores channel gains that make it render as pure gray or white.
Within color & white balance, it sits between automatic and manual control: it is more consistent than auto white balance, more precise than a fixed preset, and more practical than dialing a Kelvin value by eye when the light is unusual. Manufacturers call it preset manual, custom WB, PRE or one-push white balance, but the principle is the same.
How custom white balance measures the light
Custom white balance works by sampling the raw channel values of a target that is known to reflect all visible wavelengths equally. Under warm tungsten light the red channel of that target reads high and blue reads low; under shade the opposite happens. The camera computes multipliers for the red and blue channels relative to green that bring the three averages into balance.
Those multipliers are then applied to every following frame. In a JPEG they are baked into the processed image; in a raw file they are only stored as as-shot metadata, so a raw converter can use them as the starting point while the sensor data remains untouched. The correction includes both the blue-amber axis (color temperature) and the green-magenta axis (tint), which is why a custom setting can neutralize fluorescent or LED light that no Kelvin value alone corrects.
The typical workflow takes less than a minute and follows the same sequence on most camera systems.
- Place a neutral target where the subject will be, facing the main light.
- Fill the metering area or a large part of the frame with the target, with correct or slightly bright exposure.
- Select the custom or preset manual function and register the frame as the reference.
- Check the confirmation message, then choose the stored custom setting for the shoot.
- Repeat the measurement whenever the light changes.
Reference targets and what they deliver
The quality of a custom white balance depends directly on the spectral neutrality of the target. A surface that looks white to the eye may contain optical brighteners or a slight tint, and the camera will faithfully correct for that error. The table compares common references.
| Target | Spectral neutrality | Practical notes |
|---|---|---|
| Gray card | High, if made for photography | 18% or 12% reflectance; easy to expose correctly |
| White balance card | High | Brighter white surface; avoid overexposure |
| Color checker gray patches | Very high | Small patches; better for later raw correction |
| Translucent diffuser cap | Moderate to high | Measures incident light from the camera position |
| Copy paper | Variable | Optical brighteners often add a blue bias |
| White wall or ceiling | Low to variable | Paint tint and reflected color distort the result |
Exposure of the reference matters as well. If any channel clips at full saturation, the ratio between channels is lost and the camera may reject the frame or produce a cast. A target exposed about half a stop to one stop above middle gray gives a clean reading without clipping. Focus is irrelevant, so a defocused target works well and hides surface texture.
Custom white balance compared with other methods
Custom white balance is one of several ways to reach neutral color, and each method answers a different need. The comparison below shows where it fits among the neighboring approaches in color & white balance.
| Method | Basis of correction | Strength | Weakness |
|---|---|---|---|
| Auto white balance | Scene statistics and algorithms | Fast, no setup | Drifts between frames; fooled by dominant colors |
| Presets | Fixed values for typical sources | Predictable | Real sources rarely match the preset |
| Kelvin setting | Manually chosen temperature | Repeatable, quick | No tint correction; needs experience |
| Custom white balance | Measured reference under actual light | Accurate on both axes | Must be redone when light changes |
| Raw correction later | Click on neutral area in software | Flexible after the shoot | Requires a neutral area in every scene |
The key distinction is that a custom measurement captures the real spectral mix at the subject position, including reflections from colored walls, foliage or a tinted window. A Kelvin value describes only an idealized light source on the blue-amber axis, so it cannot account for a green or magenta tint from fluorescent tubes or inexpensive LED panels.
When a custom setting is worth the effort
Custom white balance pays off most when color consistency across many frames matters more than speed. It also matters when the output is JPEG or video, because correcting a baked-in color cast later costs quality. The decision table summarizes typical situations.
| Situation | Recommended approach | Reason |
|---|---|---|
| Product or catalog work | Custom white balance | Accurate, repeatable color across a series |
| Video or JPEG delivery | Custom white balance | Correction is recorded into the file |
| Fluorescent or LED interiors | Custom white balance | Corrects tint as well as temperature |
| Raw stills with time to edit | Gray card frame plus raw correction | Same accuracy, decided later |
| Fast-changing outdoor light | Auto or daylight preset | Constant remeasuring is impractical |
| Sunset or candlelit mood | Kelvin or preset | Full neutrality would remove the atmosphere |
The last row points to an important principle: neutral is not always desirable. A custom measurement removes warmth that the viewer expects in a sunset or a fireside portrait. Many photographers measure a custom value and then apply a deliberate white balance shift toward amber to keep some of the mood.
Limitations and common mistakes
Custom white balance is only as good as the conditions of the measurement, and most failures come from a mismatch between the reference and the subject. The symptoms below are typical in practice.
| Symptom | Likely cause | Fix |
|---|---|---|
| Blue cast on all frames | Paper with optical brighteners | Use a dedicated gray or white card |
| Error message when registering | Reference clipped or too dark | Adjust exposure of the target frame |
| Subject warmer than target | Target placed in different light | Measure at the subject position |
| Color shifts during the day | Light changed after measurement | Remeasure at each change |
| Mixed casts within one frame | Mixed lighting from several sources | Gel or block one source; one setting cannot fix both |
The last case is the hard limit of the method: a single white balance setting applies one correction to the whole frame. When window daylight and tungsten lamps both light the subject, any measured value is a compromise. Matching the sources with color correction gels or using local adjustments in editing is the only real solution.
Some sources also have a discontinuous spectrum, so a neutral gray card can render correctly while saturated colors still look wrong. That is a limitation of the light quality, not of the measurement, and it is corrected with a camera color profile built from a color checker rather than with white balance alone.
The short version
Every light has its own color. A lamp at home is orange, shade outdoors is bluish, and some office lights are slightly green. Our eyes adjust automatically, but a camera needs to be told what white should look like.
Custom white balance is like showing the camera a sample of white before you start. You photograph a plain gray or white card in the same light as your subject, and the camera learns exactly how much to correct. Everything shot afterward in that light looks natural, until the light changes and you take a new sample.
Where it makes a difference
A photographer shoots 120 handbags for an online shop in a small studio lit by two LED panels and a window. In auto white balance, the white bags come out neutral but the brown leather pieces pull the camera toward a cooler rendering, so the same background shifts color from frame to frame.
She places a gray card at the product position, registers it as custom white balance and also adds the card to the first frame of each set. The panels turn out to have a slight green tint that the 5600 K preset did not remove. With the custom setting, the background stays identical across the series and the leather colors match the real products, which reduces returns from customers who complain that an item looked different online. When afternoon sun starts to enter through the window, she remeasures before continuing.