Applying an electric charge to the liquid crystals causes the molecules they are made up of to realign themselves, altering the transparency of that layer. (The screens of portable computers work in a similar way.) The result is that a high-resolution negativecopy of the moving image is formed in the liquid-crystal layer.
When all the finishing touches are complete, the master copy of the movie will reside not as a film negative but as a computer file, several terabytes in size (exactly how many terabytes, no one yet knows).