When first married we lived next door to a pro painter. He taught us a lot and one day told me that he just got done painting a 3 bedroom apartment - and he did it all that day and was not spraying. I still don't know how that could be done that fast. But then he could do all sorts of stuff. I went over to his house one day and he had decided to paint the runners on his drop ceiling in the basement. He was painting them black and did not move the panels at all and there was not a black mark on any of the white panels.