In 1889, Thomas Edison’s assistant, W. K. L. Dickson essentially created the aspect ratio (relationship between height and width) for motion pictures that would be used by most filmmakers for more than six decades, at random (Belton, 1992). A 35mm-wide film stock with an image in a ratio of around four (width) to three (height) would be the industry standard from the earliest days of the silent era until the widescreen revolution of the early 1950s. Yet this is generally referred to as the Academy ratio, in reference to a 1932 decision by the Academy of Motion Picture Arts and Sciences (AMPAS) to impose particular dimensions as an industry-wide standard. The institution of the Academy ratio is a historical reality brought on by a unique set of circumstances, including the industry’s weariness of change in the wake of the conversion to sound production and the onset of the Great Depression. 

Some of the earliest activities of AMPAS involved creating aperture standards for both cameras and projection. Though there were commonly used ratios, these had never been standardized and had been thrown in chaos both by the coming of sound and by several studios attempting experiments in wide-gauge film stock and widescreen, such as the 70mm Fox Grandeur and 65mm Vitascope formats. The introduction of sound-on-film technologies such as Movietone in the late-1920s, which created a narrower 1.19:1 image, meant theaters were having to creatively deal with the problem of the soundtrack appearing on the screen. 

The Academy’s newly formed Technical Bureau took on this problem, looking at various theaters’ solutions, such as drapes, mattes, flippers, and using undersized aperture plates (AMPAS, 1929a: p. 3). A Subcommittee on Aperture Practice was convened within the Bureau, consisting of Virgil Miller (chair), Sidney Burton, Joseph Dubray, George Mitchell and Donald Gledhill. In 1929, the Bureau hastily assembled a recommendation that studios compose for sound-on-film in 0.835in by 0.620 in (21.21mm x 15.75mm), and theaters use an aperture on their projectors to project in 0.80 in by 0.60 in (20.32mm x 15.24mm) (AMPAS, 1929b). This was seen as a stopgap recommendation, rather than an industry-wide imposition.

Over the next couple of years, several studios attempted to introduce widescreen technologies, seeing this as the next area for innovation after the incorporation of sound. The Academy did not want to get involved, as it generally stayed away from any technologies it saw as competitive between the studios. Likewise, the Society of Motion Picture Engineers (SMPE) took a passive approach to industry practices – willing to analyze the pros and cons of various systems, but not to impose any kinds of standards. 

After several widescreen/wide-gauge films were released in 1930 with little success, many in the industry turned against the technologies. Not only did they not want to invest in them, they did not want their competition to use them either. With the studios reliant on each other to show their films in each other’s theatres, it was economically advantageous to have everyone working with the same technologies. A concerted campaign began against wide film, with both MGM and Universal publicly declaring that they would have no wide films in their 1931–32 programs (Anon., 1931a: p. 8; Anon., 1931b: p. 1).

Now that the tide had turned against wide film and sound technology had stabilized, in the latter half of 1931, the AMPAS Technical Bureau convened a committee to gather data from the studios and theaters in order to form an industry standard for aperture (AMPAS, 1931a: p. 9). In focusing on the 4:3 ratio, the Academy invoked the tradition of Edison and presented it as a restoration of the most psychologically and aesthetically pleasing shape possible (AMPAS, 1931b: p. 3). Numerous economic advantages were mentioned, such as reducing the time needed to adjust the camera to various apertures, reduced variety of equipment and wattage in lighting, and building smaller sets. They claimed it would improve quality by allowing for “better composition” and more control over what would be seen in the theater. Likewise, the Academy enumerated several advantages for theaters, particularly the ability to do away with makeshift adaptations, and assurances that they would receive uniform prints from all of the studios.

The producers quickly agreed to the standard presented to them by the Technical Bureau. However, it took more negotiation to get the theaters on board. Harry Rubin, chief projectionist at Publix-Paramount, argued that the chosen ratio for exhibition favored the proportions of smaller houses and would actually penalize Class A houses, given that they would need to project at a picture-distorting angle to avoid their balconies (Anon., 1931c: p. 21). While Rubin fought to get the proposed 0.820 in x 0.615 in (20.83mm x 15.62mm) to 0.825 in x 0.590 in (20.96mm x 14.99mm) (approximately 1.40:1), when an Academy official met with the major chains and the Projection Advisory Council in New York, they agreed on a 0.825 in x 0.600 in (20.96mm x 15.24mm) compromise (Anon., 1931: p. 10). SMPE approved the dimensional standards for 35mm camera and projector aperture at their May 1932 meeting with no mention of where the standards came from (Anon., 1932: p. 924). With Hollywood films dominant across the globe, the Academy ratio likewise became an unofficial international standard used by producers and exhibitors around the world. 

The Academy’s ratio was a work of compromise and consensus, built on a vague artistic theory about an ideal shape. Yet it ultimately parroted a proportion chosen by Dickson decades earlier. Although Academy ratio required new aperture plates, it allowed theaters to return to the masking and proscenium practices that they had followed in the silent era without a significant investment in new equipment. The Academy ratio merely reduced the aperture height to recreate a familiar ratio, mitigating the way the width had been reduced by the addition of the optical soundtrack. It proved easier to gain agreement on the ratio everyone had grown accustomed to than to get everyone to agree on a new, wider look for the motion pictures.     

This standard remained consistent until the industry was broken open in the 1950s by changing economic incentives, industry structures, and technologies such as CinemaScope. With the industry once again in flux and looking to bring back audiences lost to television, studios reintroduced widescreen technologies, likewise opening the door to great aperture experimentation (including cropping Academy ratio films into a variety of wider ratios). While the Academy ratio seemed to disappear from Hollywood seemingly overnight, it continued to thrive in international and art house cinema and experienced revival once nostalgia for the bygone era set in. 

In recent years, the resurgence of the Academy ratio – in films from The Artist (2011) to The Tragedy of Macbeth (2021) – has been seen as a throwback to the time when the ratio dominated the world’s screens. However, current filmmakers’ ability to choose the ratio – which is one among several possibilities, including the more common 1.85:1 and 2.35:1 – is indicative of changes in exhibition that have made it easier to switch between formats. Today’s theaters require only the flip of a switch to move curtains into various screen shapes. A film such as The Grand Budapest Hotel (2014) is able to use multiple aspect ratios without causing problems in exhibition in ways that were impossible in prior decades.