Panasonic F10 MARK II Operating Instructions Manual page 30

Whenever the blinking WHITE is displayed in the
viewfinder during camera operation, the white
balance should again be reset.
It is recommended that the white balance should
be set after a few minutes warm-up.
The white balance is kept holding even if the
camera is set to standby mode.
Therefore, if the lighting condition of the scene is
exactly same as previous setting, it is unnecessary
to reset the white balance. However if the
lighting condition is different from the previous
condition, it should be reset.
If the camera is not in use of a long period of
time, it is recommended to set the white balance
prior to recording.
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