Quote Originally Posted by icicle
Shooting a grey card is not the same thing as shooting a white card.
And can Somebody correct me if I'm wrong;
Grey cards are for setting the exposure level to a neutral setting.
White Card are for setting the white balance for the shots at that time.

If you haven't noticed that natural light is not the same over the coarse of the day, and light bulbs are constantly flickering at the rate of 60 cycles a second, so in reality the human eye does not notice then doing that, but a camera will.

I will post a sample between custom white and auto white later tonight sometime.
Any shade of grey or white will work for white balance as long as it's color neutral.