In 2011 they held a direct, live, side-by-side comparison of 15/70 IMAX film vs 4K DLP at Moody Gardens in Galveston, TX. The general consensus among the industry professionals was that the 4K image was superior. I can only imagine that Imax’s laser system is superior to that Barco DLP projector. So I don’t doubt that by standardized metrics the Laser system is technically superior to the film system.
http://www.lfexaminer.com/20110518shootout-in-galveston-1570-vs-digital.htm
But it doesn’t change the fact that imax film is flipping amazing an can resolve FAR more detail than even the best digital mediums. Whether that detail makes it to the projected image is more debatable I guess. And resolution is far from the end-all be-all of image quality. Brightness, contrast, and color reproduction are all just as important as resolution.
But does it look like film? Superior isn’t always better. And everyone involved has every reason to stack the deck in favor of digital.
I don’t know about that shootout, but I can say that I’d be really hard pressed to say the two IMAX Laser screenings I’ve seen were in any way inferior to the numerous 15/70 screenings I’ve been to. The amateur film lover/historian/preservationist in me went into Dunkirk secretly wanting to walk out and declare film was still king, but I just couldn’t. That dual 4K projection system they’ve cooked up really impressed me. Personally, I do still prefer film and would jump at any reasonable chance to see another 15/70 screening. But realistically I’m perfectly happy to walk into a full size Imax laser screening when I want the premium theatrical experience.