White Balance
Is the white balance dropper looking for an 18% gray card, or an actual pure white pixel?
PowerBook G4 Mac OS X (10.4.3)
Works fine for me when choosing a pure white, but
gray should also be fine, if it's a true gray (i.e.
the RGB values are equal in reality)... Remember that
a gray card may not be produced in color neutral
fashion unless it's marketed as such... Conceptually
and mathematically there should be no difference
between "pure white" and "pure gray." After all, a
fully pure white value of 255.255.255 is not valid
for setting white balance, thus anything you can set
by is really "gray."
3. WhiBal gray is imperfect, and you previously
compensated for it somewhere else.
White Balance