I'd like to suggest to anyone shooting in manual that they take three pictures in the same light with their camera meter centered for normal exposure for each of:

a) a black piece of card
b) a 17% gray card
c) a white piece of card

Look at the resulting images and look at the histograms.

Next, meter and shoot the gray card again, then shoot the black card and the white card, but without adjusting your exposure.

Look at the resulting images and histograms and compare them with the previous batch.

Can you explain what you see and why?