White Balance and Color Temperature

Different light sources emit light of different colors, described by color temperature measured in Kelvin (K). Counterintuitively, 'warm' light sources (candles, tungsten bulbs at 2700–3200K) have low Kelvin values and produce an orange-yellow cast; 'cool' light sources (overcast sky, open shade at 7000–10000K) have high Kelvin values and produce a blue cast. Standard daylight/flash falls at approximately 5000–5500K and appears neutral white to human vision. The human visual system continuously adapts to different color temperatures — when you walk from warm office lighting into outdoor daylight, your eyes adjust and both appear 'white.' Camera sensors do not adapt automatically — without white balance correction, a photo taken under tungsten lighting looks intensely orange; a photo in open shade looks blue. White balance correction instructs the camera sensor to compensate for the color of the ambient light source by adding the complementary color shift. Setting WB to 'Tungsten/Incandescent' (2700K) adds a heavy blue correction to counteract the orange cast of tungsten bulbs, producing a neutral image. Setting WB to 'Cloudy' (6000K) adds a warm yellow correction to counteract the blue cast of overcast light. Auto White Balance (AWB) reads the scene and estimates the correction — reliable in neutral, single-source lighting but can fail in mixed lighting, for deliberate warm sunset effects, or in scenes dominated by a single strong color.