Right, there are at least four versions of projection all being marketed as IMAX. It’s all rather confusing.
IMAX 70mm Film
- The Original Format: Uses massive 15-perforation, 70mm film running horizontally through the gate.
- Aspect Ratio & Resolution: Delivers a towering 1.43:1 aspect ratio with a quality equivalent to roughly 16K–18K digital resolution.
- Availability: Extremely rare, found in fewer than 45 specialized mega-theaters worldwide.
IMAX GT Laser (Dual Laser)
- The Premium Digital Standard: Uses a dual 4K laser projector setup paired with a 12-channel sound system.
- Aspect Ratio & Screens: Designed to fill massive, tall 1.43:1 curved screens without cropping the original top and bottom camera frame.
IMAX with Laser (Single Laser)
- The Multiplex Standard: Uses a single 4K laser projector built for standard, smaller commercial theater retrofits.
- Aspect Ratio: Restricted to a 1.90:1 aspect ratio, meaning the image is cropped slightly at the top and bottom compared to full 1.43:1 screens.
IMAX Digital Xenon (2K)
- The Older System: Uses dual 2K xenon arc lamp projectors.
- Specs & Limitations: Limited to 2K resolution, a 1.90:1 aspect ratio, and 5.1 or 6-channel sound (often nicknamed “LieMAX” by purists).
The IMAX website notes the few 70mm IMAX theaters. It also notes whether or not a theater has the “IMAX with Laser” projection format, but does NOT tell you if it’s dual-laser or single laser.
And if a theater just says “IMAX”, it’s almost certainly one of the 2K Digital Xenon theaters with relatively small screens (so-called “LieMAX” theaters).
See here for more details from the other thread (thanks to @commasense):