IMAX Expanded Aspect Ratio IMAX 1.43:1 and 1.90:1 expanded aspect ratios

What the expanded aspect ratio is

A standard scope release is framed at 2.39:1, a wide, short rectangle. IMAX films keep the same width and add height, so the picture grows vertically. The theatrical IMAX system has two frame shapes: 1.43:1, the shape of the 15-perforation film frame, and 1.90:1, the shape of IMAX's digital projection. IMAX's annual report states that its 1.43:1 presentation shows "up to 67% more image" than a conventional screen, and that expanded framing delivers up to 26% more image on a standard IMAX screen. A 2020 IMAX release put the floor for the expanded ratio at "at least 26% more picture than standard theatres."

Not every minute of a film uses it. IMAX's filing says most Filmed For IMAX titles use the expanded ratio for some or all sequences, so a release can alternate between the scope frame and the tall frame. SlashGear says single-projector 1.90:1 rooms crop the 1.43:1 frame.

The arithmetic

The percentages come from dividing the frame ratios, assuming the comparison frame is 2.39:1 (my inference; IMAX does not state its baseline in the pages I loaded). At the same screen width, picture height scales as the inverse of the ratio: 2.39 ÷ 1.90 = 1.258, which is the 26% figure, and 2.39 ÷ 1.43 = 1.671, which is the 67% figure.

Worked example on a screen 20 m wide: a 2.39:1 image is 8.4 m tall, a 1.90:1 image is 10.5 m tall, and a 1.43:1 image is 14.0 m tall. Going from scope to the full IMAX frame adds 5.6 m of picture height without adding a single metre of width. That is why the real 15/70 screens are so tall: Wikipedia lists the standard 15/70 screen at 18 × 24 m (59 × 79 ft).

Why those two shapes

Both ratios come from hardware. The 15/70 film frame measures 69.6 × 48.5 mm per Wikipedia, and 69.6 ÷ 48.5 = 1.435, so the film's native shape is 1.43:1. The digital 1.90:1 frame is the shape of IMAX's digital projection chain. A production that wants to use both therefore composes for one frame and protects the other, which is how Dune: Part Two worked: one capture, three deliverables (1.43:1, 1.90:1 and 2.39:1). The sensor matters too. The Fujifilm GFX ETERNA 55, certified for IMAX in March 2026, has an Open Gate sensor of 43.63 × 32.71 mm, a 4:3 (1.33:1) shape that sits close to 1.43:1 and leaves little vertical image to throw away (my reading).

Which screens show which ratio

The 1.43:1 frame needs a screen built for it. 15/70mm film projectors fill it, as do the dual-projector laser GT systems; SlashGear's example of a GT screen is about 100 × 70 ft, which is 1.43:1. Single-projector laser rooms and the older xenon digital rooms are 1.90:1; SlashGear's example is about 60 × 32 ft. Engadget's guide to telling real IMAX from "LieMAX" notes that only a few films each year use 1.43:1 framing, typically for certain scenes. When a film built for 1.43:1 plays on a 1.90:1 laser screen, SlashGear says the top and bottom of the frame are cropped. See IMAX laser vs xenon for how the two digital tiers differ.

Films that use it

Dune: Part Two was shot entirely for the 1.43:1 frame, according to the American Society of Cinematographers, with 1.90:1 and 2.39:1 framing protected so the same shots could run in digital IMAX and standard theaters. Its main camera was an ARRI ALEXA 65, with ALEXA LF and Mini LF bodies filling in. Oppenheimer alternated: its IMAX-shot sequences expand to 1.43:1 in 15-perforation 70mm theaters, while the portions shot on non-IMAX 65mm cameras do not expand. Only 30 theaters worldwide could show that 15/70 version. The camera program behind these titles is covered in Filmed For IMAX.

The expanded ratio at home

At home the 1.90:1 version is the one that exists. Disney+ launched its IMAX Enhanced tier on November 12, 2021 with 13 Marvel titles, offering "up to 26% more picture for select sequences." Disney's own help page states the ratio as 1.90:1, says the expanded picture works on every supported Disney+ device, and lists titles including The Marvels, Guardians of the Galaxy Vol. 3 and Avengers: Endgame. A DTS article describes IMAX Enhanced as bringing the 1.43 and 1.90 theatrical versions home, but the Disney+ page documents only 1.90:1, so I treat 1.43:1 as a theater-only shape. The program is explained in IMAX Enhanced.

Worked example on a 65-inch 16:9 TV, which is 56.7 in wide and 31.9 in tall. A 2.39:1 image occupies 23.7 in of that height, or 74%. A 1.90:1 expanded sequence occupies 29.8 in, or 93%, so the bars nearly vanish and the picture area grows by the 26% IMAX quotes. A true 1.43:1 frame would be pillarboxed to 45.6 in wide, 80% of the screen width, which is why the 1.90:1 version suits a 16:9 panel better.

Common confusions

"IMAX aspect ratio" is not one number, and a film marketed as "in IMAX" may use the tall frame for 10 minutes or for most of its length. Disney+ marks the difference in its Versions tab, which says whether the whole title or only select sequences are expanded. For how the theatrical formats compare as a night out, see Infinity Vision vs IMAX vs Dolby Cinema.