How Things Work: IMAX
Movies are an integral part of American entertainment, and technology is constantly making the experience more sensational and captivating. IMAX is such an example of technology that is striving to create a more engaging viewing experience. Using cutting-edge sound systems and a screen that envelopes the viewer’s field of vision, the line between being a member of the audience and being inside the film is becoming blurred.
Anyone who has seen any IMAX film is quickly aware of how different it is from a normal movie. Perhaps the first noticeable change is the towering size of the screen. An average sized IMAX screen is 52 feet tall and 72 feet wide, but the largest ever created is 98 feet tall. This is about the height of a wide, eight-story building. The height enables seating to be contained within the height of the screen; for normal movie screens, rows of seats can extend many times above the screen. However, the size of the screen necessitates a high image quality; to achieve this, different types of equipment and film technology are used to create scenes in an IMAX film.
A larger camera and larger film is used that corresponds to larger film size. According to the IMAX website, the cameras can weigh up to 215 pounds. They are so heavy that they require special mounts just to move them around a scene.
The film is called 15/70 mm film, as opposed to the familiar 35mm film, and is 10 times as large. To save even more space on film, there is no soundtrack embedded on the film. Perhaps this is an advantage — in operation, the cameras emit a constant 65-decibel noise, which is comparable to the sound of a chainsaw.
Several other innovations in film technology have been created to enhance the IMAX experience. In theater design, “dome technology” has created a screen that completely wraps around the peripheral vision of the eye, so that everything in the field of vision is the movie screen.
Three-dimensional technology has also been created. For making 3-D films, the film is shot simultaneously in two different viewing angles, and combined when projected on the screen so that two images are shown. When viewers wear polarized glasses, each eye can only see one of the two images shown, producing the illusion of depth. IMAX HD has also been developed, which is normal film with double the frame rate. The high frame rate helps enhance the visual details.
To compensate for the large film size, the film projector is gargantuan, weighing over two tons. The mechanisms of the projector are so complex that projectionists, whose job is to change the xenon lamps in the projector, are required to wear body armor when handling the bulbs.
Regular movie projectors work by feeding film vertically into the top of the projector, advancing the film one frame at a time through the use of a claw, and shining a light through the film onto a screen for a short period of time. IMAX differs completely from this because the film is too heavy.
The film projector increases image resolution by moving the film sideways through the camera at a rate three times higher than normal. Mechanical claws are too imprecise for heavy film, so vacuums are used to suck the film into the proper position in front of the lens. More light is needed for each frame, which is why xenon lamps are used.
In addition to mechanical problems that need to be overcome, artistic direction needs to be heightened as well. The quality of the image is remarkably high at 70 megapixels. At this resolution, the eye finds faults in images quickly. Therefore, computer-generated imagery must be flawless. Also, since images on the screen look so close to real life, sometimes the brain cannot interpret all of the information at once. Hence, objects on the screen have to be positioned so as to not divert attention from the main image.
The popularity of IMAX is rapidly increasing despite the costs of production and the price of movie tickets. Many say the film and camera system of IMAX are too cumbersome to be used in mainstream film-making, but new technology such as digital projection systems are being developed that might cause film prints to become obsolete. Also, new technologies, like IMAX DMR, are capable of converting normal 35mm prints into the IMAX standard films.
More and more IMAX theaters are appearing across the nation. Perhaps the future of movies has already been in theaters: The Dark Knight was shot partially with IMAX cameras, making the viewer feel like a participant in the movie.