Anamorphic widescreen

Anamorphic widescreen is a process by which a comparatively wide widescreen image is vertically expanded to fit into a storage medium (photographic film, for example) with a narrower aspect ratio. Compatible play-back equipment (a projector with modified lens) can then recompress the vertical dimension to show the original widescreen image. This is typically used to allow one to store widescreen images on a medium that was originally intended for a narrower ratio, while using as much of the frame - and therefore recording as much detail - as possible.