So in a nut shell, if you car has just come out of the paint shop and is one color these areas would get blacked out.

1) Rad support,fenders(behind grille),hood lip(brush)

2) Fender tab for the firewall strut, rocker pinch weld(both brush)

3) Back of the door (depending on interior color, may not be black)

4) Winshield frame (brush)