The magic of movies relies upon chemicals that can filter light. These chemicals need to stick to something so that they can be moved into position and then moved away using gears and motors and pull down levers and reels. What those chemicals required was a base that they could be printed upon and woven through the machine. A piece of board wouldn't do. Plastics hadn't been invented or refined. Cellulous was part of the key, and it was combined with a nitrate in the base. That is where the story begins.