Chromatic adaptation is the ability of the human visual system to adjust its perception of color based on the illuminating light source. A white piece of paper looks white whether you're in warm tungsten light or cool daylight — even though the physical light reaching your eye is vastly different. In digital color science, this phenomenon must be modeled mathematically.
White Balance in Photography
What photographers call "white balance" is a practical application of chromatic adaptation. A photo taken under tungsten light (warm/orange) and one under daylight (cool/blue) will have different color casts. Correcting white balance is essentially telling the algorithm: "this specific pixel should be neutral white — adjust everything accordingly."
The Bradford Transform
The Bradford chromatic adaptation transform is the industry standard for converting colors between different illuminant white points. It works by:
- Converting XYZ tristimulus values to a "cone response" domain via the Bradford matrix
- Scaling the cone responses to match the ratio between source and destination white points
- Converting back to XYZ
Common white points include D50 (warm daylight, used in print), D65 (average daylight, sRGB standard), and illuminant A (tungsten).
In Generative Art
Generative art often combines reference palettes from different sources. A palette sampled from a sunset photo and another from an indoor scan will have different white points. Understanding chromatic adaptation helps explain why naively mixing these palettes can produce unexpected results, and how to correct for it.