The IMAX Technology
As mentioned earlier, the IMAX mission is to provide the most immersive and entertaining cinematic experience. This starts with providing a huge screen with bright and colourful high resolution images and seating close to the screen the house gets a great, sharply focused, uniformly bright picture, not just the “money seat”. IMAX isn’t about compromises.
Back in the 1970s, films were shot and presented in an analog format. Typically most large budget films used a 35 MM size (width), and were vertically fed through the projector at a rate of 27.4 meters per minute, while IMAX uses a 70 MM wide film frame size, and is fed through the projector horizontally (easier to control for the large film size) at a rate of almost four times as fast, of 102.7 meters per minute.
In today’s digital standards, 1080p HD represents a size of 1,080 vertical lines or pixels by 1,920 horizontal lines or pixels -sometimes loosely referred to as 2K for the number of horizontal lines or pixels. A typical 35 MM film would represent approximately three times the HD horizontal resolution at 6K horizontal lines or pixels, while a 70MM IMAX film would represent a substantially larger 18K horizontal lines or pixels. The IMAX 70MM format is almost ten times the horizontal resolution of our commonplace HD systems.
The accompanying illustration shows the difference in the picture content between 35 MM and IMAX 70 MM film. The 35mm Academy standard also includes an audio track located between the picture and the left sprocket, while IMAX uses a separate audio track not contained on the video recording. The IMAX audio originally used a 35 MM film containing six separate audio channels and was locked to the video system.
A comparison of 35MM and IMAX 70 MM film.