Nikon D90 - Manual (Page 123)

103
t
A Preset d-0
The new value for white balance will be stored in preset d-0,
automatically replacing the previous value for this preset (no
confirmation dialog will be displayed). A thumbnail will be displayed
in the preset white balance list.
To use the new value for white balance, select preset d-0 (if no value has been measured for
white balance before d-0 is selected, white balance will be set to a color temperature of
5,200 K, the same as Direct sunlight). The new white balance value will remain in preset d-0
until white balance is measured again. By copying preset d-0 to one of the other presets before
measuring a new value for white balance, up to five white balance values can be stored (pg.
104).