Film Guides / Film formats and cinema tech
Aspect ratios explained
What 1.85:1, 2.39:1, 1.43:1 and 16:9 mean, how the shape of the screen changed through film history, and why some movies have black bars at home.
The aspect ratio is the shape of the picture: its width divided by its height. A ratio of 2.39:1 means the image is 2.39 times as wide as it is tall. The choice of shape affects how a film feels, from the intimate near-square frames of classic Hollywood to the sweeping widescreen of an epic.
The main ratios
| Ratio | Common name | Where you see it |
|---|---|---|
| 1.33:1 (4:3) | Full frame | Silent films, old TV |
| 1.375:1 | Academy ratio | Hollywood sound films from the early 1930s to the 1950s |
| 1.43:1 | IMAX film | Full-height IMAX screens |
| 1.78:1 (16:9) | HD widescreen | TVs, streaming shows, online video |
| 1.85:1 | Flat | Many comedies, dramas and animated films |
| 1.90:1 | IMAX digital | Most multiplex IMAX screens |
| 2.20:1 | 70mm | Classic 70mm presentations |
| 2.39:1 (often called 2.35 or 2.40) | Scope | Many blockbusters and epics |
| 2.76:1 | Ultra Panavision 70 | Rare ultra-wide 70mm films |
A short history of screen shapes
Early films used a frame about four units wide by three units tall. When sound was added to the film strip, part of the frame was taken up by the soundtrack. In 1932 the Academy of Motion Picture Arts and Sciences standardized a slightly wider Academy ratio of about 1.37:1 so pictures would be consistent.
In the 1950s, as television kept audiences at home, studios fought back with wider images. Cinerama used three projectors on a deeply curved screen. CinemaScope, launched by 20th Century Fox with The Robe in 1953, used anamorphic lenses to squeeze a wide image onto standard 35mm film. Other systems followed, including VistaVision and Todd-AO 70mm. See widescreen and 35mm and 70mm.
How anamorphic works
An anamorphic lens squeezes a wide image horizontally so it fits on a normal frame. In the cinema, a matching lens on the projector unsqueezes it. Anamorphic photography also creates distinctive looks: oval out-of-focus highlights and horizontal lens flares, which many filmmakers love even in the digital era.
The alternative is spherical photography, where the image is captured normally and the top and bottom are masked or cropped to create a wide shape.
Why ratios matter to filmmakers
- Wide ratios suit landscapes, large groups and visual scale.
- Taller ratios suit faces, vertical spaces and intimate stories.
- Changing ratios within a film can mark a shift in time or mood. Some recent films expand to IMAX's taller frame for big set pieces.
Black bars at home
TVs are 16:9 (1.78:1). A 2.39:1 film is much wider, so it appears with black bars above and below: letterboxing. A 4:3 film on a 16:9 TV shows black bars on the sides: pillarboxing. Before widescreen TVs, films were often cropped with pan and scan, which cut off a large part of the original image. Letterboxing preserves the filmmakers' composition, which is why it is now standard.
If you want to see a scope film as big as possible in a cinema, choose a screen that is natively wide. On IMAX screens, standard scope films are shown letterboxed. See seats and formats.
Quick ways to identify a ratio
| What you see on a 16:9 TV | Likely ratio |
|---|---|
| Fills the screen | 1.78:1 |
| Thin bars top and bottom | 1.85:1 or 1.90:1 |
| Thick bars top and bottom | 2.39:1 |
| Bars on the sides | 1.33:1 or 1.37:1 |
| Bars that come and go | Variable ratio, often IMAX scenes |
