Every part of the page is illuminated with reflected light from your forehead, your nose, your chin, and every other part of your face. You don't see an image of your face on the page because there is too much overlapping of light. But put a barrier with a pinhole.....
The "overlapping of light" part seems very vague to me. Could somebody shed some more light on it?(Pun not intended)
Note: This is an extract from Hewitt's Conceptual Physics.
