The EXIF WhiteBalance tag (0xA403) answers a single yes-or-no question: did the camera set white balance automatically (0, Auto) or was it set by the photographer (1, Manual)? Daylight, Tungsten, a custom Kelvin value: as far as this tag is concerned, any choice other than auto white balance counts as Manual. The details live elsewhere, if anywhere.
Three layers of white balance data
LightSource (0x9208, SHORT) names the illuminant. It predates WhiteBalance and has a long table; a selection:
| Value | ExifTool prints |
|---|---|
| 0 | Unknown |
| 1 | Daylight |
| 2 | Fluorescent |
| 3 | Tungsten (Incandescent) |
| 4 | Flash |
| 10 | Cloudy |
| 11 | Shade |
| 17 | Standard Light A |
| 21 | D65 |
| 255 | Other |
Many files leave it at 0 or skip it entirely. The third layer, and the only one with real numbers, is the maker notes: color temperature in Kelvin, per-channel multipliers, fine-tune shifts. A Canon EOS RP JPEG on auto white balance:
$ exiftool -a -G1 -s -WhiteBalance -LightSource -ColorTemperature photo.jpg
[Canon] WhiteBalance : Auto
[ExifIFD] WhiteBalance : Auto
[Canon] ColorTemperature : 5200
$ exiftool -a -G1 -s -n -WhiteBalance -LightSource -ColorTemperature photo.jpg
[Canon] WhiteBalance : 0
[ExifIFD] WhiteBalance : 0
[Canon] ColorTemperature : 5200No LightSource tag at all, and a 5200 K figure that only exists in Canon's private block. How that number relates to what auto white balance actually chose varies between brands and models, so read it as a hint, not a measurement.
JPEG versus RAW
In a JPEG, white balance has already been applied to the pixels. Changing the tag afterwards recolors nothing. In a RAW or DNG file the opposite holds: the camera's white balance is a stored recipe that the converter applies, which is why Lightroom's "As Shot" setting can read it and why stripping maker notes from a RAW file is a bad idea. Flash changes the color of a scene as well; the Flash tag records whether it fired, but standard EXIF has no field for the flash's color temperature.
Setting WhiteBalance and LightSource
The EXIF editor offers Auto and Manual for WhiteBalance in JPEG and TIFF files. LightSource is not in our list, so use ExifTool, by name or by number:
exiftool -LightSource=Daylight photo.jpg
exiftool -LightSource#=21 photo.jpgFor the other camera settings EXIF records next to these, see what EXIF data is.