libcamera-still -n 1 --width 4056 --height 3040 -o test.jpg --awb custom --awbgains 0.9,2.0
In --awbgains 0.9,2.0 , 0.9 is the gain for the red channel and 2.0 is the gain for the blue channel.
In other words, if your image is:
- too red -> decrease the first number
- too blue -> decrease the second number
- too yellow -> increase the second number (blue)
- too green -> increase both numbers
- etc