Nikon D300 User Manual page 38

The camera can store up to five values for preset white balance in
presets d-O through d-4. A descriptive comment can be added to
any white balance preset (pg. 144).
d-O
Stores last value measured for
white balance (pg. 136). This
preset is overwritten when a
new value is measured.
d-l-d-4
Store values copied from d-O (pg. 139).
Store values copied
from images on
memory card (pg. 140).
[] White Balance Presets
Changes to white balance presets apply to all shooting menu banks
(pg. 255). A confirmation dialog will be displayed if the user attempts to
change a white balance preset created in another shooting menu bank
(no warning is displayed for preset d-0).
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