Using the double-sided printing process, movie posters are printed on both sides of the paper. The image on the back side is usually reversed and lighter than the front image.

A lightbox (light box) refers to an encased frame (or box) for a movie poster that is lit from behind. They're generally best suited for double-sided posters.

Double sided movie posters refer to a poster where the image is printed (in reverse and a little lighter) on the back side of the poster instead of leaving it just white.