How cinema is captured and presented through the IMAX format

Cinema has always been a home to spectacle. Most theatrically released cinematic works, especially till the development of digital photography, employed the use of 35 mm film stock to capture the stunning vistas and cinematic protagonists. For the bulk of its history, almost all movies were shot using this 35mm film. Most modern cinematic productions have since replaced the 35mm film stock with a digital sensor. But film purists argue that film stock provides for superior resolution.

Standard film stock is a photochemical emulsion with a total width of 35mm, which records images passing vertically through a camera. Some of that frame width needs to be used to accommodate sprocket holes, which are called perforations (or perfs, if you will), that pass the film through the camera. A standard 35mm film stock has four perforations. As must be self evident, a larger surface area on a piece of film would allow for more photographic information to be captured. This was made possible through the use of 70mm film stock. The expansive imagery of the American West in Raoul Walsh’s 1930 film The Big Trail was brought to light through the use of 70mm film. But it wasn’t until television started stealing viewers away from Hollywood in the 1950s that the industry recognised the benefit of making 70mm a major event.

This period led to the release of epics such as Lawrence of Arabia and The Sound of Music in the 1960s. The numbers bore out the impact that the 70mm format had with its visual resolution and superior sound quality.

It was in this period that Graeme Ferguson, Roman Kroitor, Robert Kerr, and William C. Shaw came together to develop what would become IMAX.

What is IMAX?

IMAX is a motion picture film format. It consists of a production pipeline of high-resolution cameras, film formats, projectors, and theatres. Developed in Canada in the 1970s, IMAX seeks to give the viewer an immersive movie-watching experience with its large screens. IMAX theatre screens have a tall aspect ratio of 1.43:1, meaning that the width of the screen is 1.9 times the height of the screen. The screens can be 18 by 24 metres in size, with the largest screen in Leonberg, Germany, measuring 38.8 metres by 21 metres.

The IMAX negative frame has a size of 70x48mm, nearly eight times the size of what a traditional cinema film stock can capture. The IMAX format uses 70 mm film run horizontally through the projector. In normal film projection theatres, a 35 mm or a 70 mm film is run vertically. Because of this horizontal orientation, the IMAX format produces images that can be screened at 8.3 times the size as a regular 35 mm film or 3.4 times as large as the regular 70 mm film. The larger the surface area of a piece of film, the more photographic information it will contain. This means that an IMAX image yields more detail in the image.

IMAX cameras are notably larger and bulkier compared to standard cinema cameras. This size is primarily due to the large film format they use. This larger film size allows for higher resolution and clarity. Digital IMAX cameras, while smaller than their film counterparts, are still larger than most standard digital cinema cameras due to their advanced sensors and technology. The IMAX film format provides an extremely high resolution vis-à-vis its 35mm counterpart. In fact, theoreticians estimate that a standard 35mm film would have a digital resolution of around 4k, whereas a standard 70mm film would resolve at around 8k. In comparison, the IMAX format is estimated at having an equivalent digital resolution of 18k.

As a capture and storage medium, film can last indefinitely. This means that future generations could witness even more detail lurking within an IMAX frame when digital projection technology catches up.

Big screen, big business

The Dark Knight was the first major motion picture to be filmed with high-resolution IMAX cameras, and its billion dollar box office result along with its many award nominations, including for its cinematography, cemented IMAX’s potential as a motion picture format. The success of Christopher Nolan’s other movies, The Dark Knight Rises, Interstellar, Dunkirk, and his most recent Oppenheimer, all of which employed the IMAX format, have made its commercial potential evident. It has also sparked an interest in other filmmakers such as J.J. Abrams (Star Wars: The Force Awakens), Michael Bay (Transformers: Revenge of the Fallen) and Damien Chazelle (First Man) who also employed the format.

There is also a trend of conventionally shot films being upscaled to be projected on IMAX screens; the improved sound quality and visual appearance is supposed to enhance the viewing experience. IMAX has, in recent years, also ventured into digital filmmaking with its own slew of certified high-fidelity digital cameras that can be used to create IMAX-format films. The first film to employ such a camera was Captain America: Civil War following which many blockbuster movies including Top Gun Maverick as well as the Dune films were shot using this format. With films being converted to the IMAX format, the market seems to be saturating with the format. There is also concern that with such a vast stockpile of digital productions in their pipeline, the IMAX film format which is what cemented its position in the first place might become a thing of the past. However, there are filmmakers such as Christopher Nolan, Jordan Peele, Ryan Coogler and others who continue to boost the IMAX film format.

Heavy lies the crown

As with all things in life, IMAX does come with its own downsides.

The first, and possibly the most evident, drawback is cost. IMAX film cameras are notoriously expensive to rent. This combined with the cost of buying and processing the amount of 65mm film, which because in IMAX’s film runs horizontally, is also considerably higher. With 15 perforations per frame moving through the camera’s gate 24 times per second, over 300 feet of 70mm film is required for every minute that is shot. The IMAX cameras are also incredibly noisy given that 15 perforations of film need to run through the camera much faster than a regular four perforations 35mm film. This makes it difficult if not impossible to record synchronous audio and forces filmmakers to do Automated Dialogue Replacement (ADR). This additional cost of dubbing the dialogue over is compounded by the bulkiness of the IMAX cameras. The heavy cameras were not designed to be handheld forcing filmmakers to use additional equipment such as a dolly, cranes, tripods, and other devices to mount the cumbersome IMAX camera.

However, given its increasing demand in tentpole films, IMAX has said it is working to improve the specifications on its camera technology. This would theoretically make their hulking cameras more mobile and also reduce its mechanical noise. These technical developments, as well as the continued use of the format in the production pipelines of many major films, suggests that IMAX is here to stay.