In the fascinating neutrino experiment that may have detected faster than light particles, they use "bricks" of film and lead. Each brick has, it seems, 8 sheets of film. There are 150,000 bricks. That would be 1.2 million sheets of film. That's a lot of film. http://operaweb.lngs.infn.it/spip.php?rubrique39 http://operaweb.lngs.infn.it:2080/spip/IMG/jpg/CIMG2821.jpg http://en.wikipedia.org/wiki/OPERA_experiment I wonder, what film is it?