Take a look at the two movie screens in the photos below. Notice anything different?
Merriam-Webster defines motion picture aspect ratio as “the ratio of the width of a television or motion-picture image to its height.” An aspect ratio of 4:3 can refer to an image (or screen) that is four feet wide and three feet tall, or one that is twelve feet wide and nine feet tall. The image may be as large or small as you like, as long as the same ratio between the width and the height is maintained.
During the first fifty years of movie-making in the United States, aspect ratios were fairly standard and produced an image that is much more square than the screens we are now used to. Silent full-frame films were often displayed at the 4:3 aspect ratio (also expressed as 1.33:1). In 1932, the Society of Motion Picture Engineers adopted the Academy ratio (1.37:1) for sound films produced in Hollywood. Most of the motion picture films held at the National Archives were shot to be displayed at one of these two aspect ratios.
In the early-1950s, Hollywood studios began experimenting with fitting wider images onto 35mm film. The new widescreen productions provided audiences with a viewing experience much more expansive than that of their television screens. For example, the CinemaScope format used an anamorphic lens to squeeze a widescreen image with an aspect ratio of up to 2.66:1 onto a piece of film that typically held a 1.37:1 unsqueezed image. Here’s what that looks like:
Government films were rarely shot using anamorphic formats and are not common in the holdings of the National Archives. In eight years I have only encountered three such items. We recently digitized our first anamorphic widescreen film, Bridge to Space (1968), shot with a Panavision lens at an aspect ratio of 2.35:1. The film, directed by Robert Gaffney, provides an impressive tour of Kennedy Space Center.
The image on the film was very obviously squeezed into the frame, so we knew it was anamorphic. Our task during digitization was figuring out just how much the image had to be stretched to remove all distortion.
The first step was scanning the film with a special anamorphic lens attachment. This allowed us to capture a 16:9 image that partially unsqueezed the image.
From there the image was digitally fine-tuned. Using a typical widescreen aspect ratio (2.35:1) as a target, we calculated the height and width necessary for a flat, undistorted image.
Because of the work done with Bridge to Space, we now have a digital template that will help us easily return anamorphic films to their widescreen glory!