I'm curious as to why and what the differences are between like named emulsions for roll and sheet films. For example, the 'old' Tri-X sheet film was rated by kodak as iso 320, in 120 you could get either iso 320 or 400 and in 35mm only 400. I am curious because I just shot a roll of (new)tmax 100 in the family Olympus Stylus and WOW! I know tmax 100 sheet film has been used by some well respected photographers and am curious about the differences, if any, between the roll and sheet films having the tmax 100 handle before I throw caution to the wind and get yet another box of that expensive yellow stuff to play with. My question then, is: What difference is there between the roll and sheet versions of the new tmax 100? Anyone have a theory?