Rafomac News, Tech & Trends That MatterIMAX isn’t just about those towering screens—it’s about the colossal film itself. A single frame of IMAX 70mm film is nearly 10 times larger than a standard 35mm frame. Unpacking how this giant strip is handled and projected reveals a blend of engineering marvel and old-school craftsmanship.
Why IMAX Film Feels Like Heavy Lifting
When you think about IMAX, you picture mammoth screens and razor-sharp images. But the real surprise is the physical size of the film frame itself. IMAX 70mm film runs horizontally through projectors and boasts 15 perforations per frame—known as 15 perf. This single frame towers over the standard vertical 35mm film frame, which shares space with soundtracks, resulting in far less detail.
In fact, an IMAX frame is almost 10 times the size of a regular 35mm frame. That scale translates directly onto the 90-foot-tall screens in IMAX theaters, offering clarity that’s visible even in a single frame.
Inside the Assembly Line for Giant Film Reels
At IMAX’s Los Angeles headquarters, technicians handle reels that are as heavy as a person and larger than an entire table. The process starts with enormous rolls of film that can stretch to a thousand feet or more, wound onto massive platters during print assembly. Staff like Irving, a veteran with over three decades in the business, oversee the splicing and prepping with remarkable precision.
They meticulously check for scratches—those can occur in cameras or in processing labs—and maintain records dating back to the 1980s. These daily reels often hold hundreds of scenes, which they splice together like a giant cinematic jigsaw puzzle. It’s old-school analog craftsmanship operating on a scale rarely seen in today’s digital world.
Plating the Film: Gigantic Reels and Complex Mechanics
Most IMAX films hit the projector on 45-inch platters, each capable of holding about an hour of footage. Longer movies get split across multiple platters, which are then combined for seamless screening in big theaters worldwide. One hour-long reel fully loaded with film can weigh around 300 pounds; a 68-inch reel holding close to three hours can tip the scales at nearly 600 pounds.
Moving these mammoth reels smoothly requires custom-engineered devices. Systems of pulleys and heavy-duty rollers channel the film up 30 feet through the building to the projector, then back down after it’s shown. The architecture itself is built to accommodate these enormous weights and the unique route the film must travel.
Projecting the Future: Film and Digital in Perfect Sync
Inside IMAX’s projection booth, multiple projectors sit on rails, enabling quick switches between digital and film sessions. Digital projection often involves two projectors working in tandem to deliver double brightness, especially for immersive 3D presentations which require separate projectors for each eye. This layering of images ensures the signature brilliance IMAX is known for.
Meanwhile, the giant film projector moves into place with mechanical precision. It can run two projectors simultaneously—for either seamless reel changeovers or stereoscopic 3D. Complementing the visuals, sound is entirely digital, synced perfectly with the film via a hard drive system, reminiscent of the DTS audio setup that revolutionized cinema sound.
The whole process blends engineering innovation with hands-on technique. The meticulous care and massive scale make witnessing an IMAX film projection not just a cinematic event, but an engineering marvel in motion.
The Director’s Perspective: Seeing Vision in Giant Scale
Directors working with IMAX often come to the in-house theater daily to review dailies—the raw footage shot that day—in the film’s massive format. Seeing those shots come alive on such a giant scale must be an intoxicating experience, with every detail crystal clear and every frame an enormous work of art. As the film rolls through the projector, you can almost sense their pride and awe watching their vision unfold in the largest film format the world has ever known.
