A projectionist’s guide to 'Oppenheimer' IMAX 70mm

Everybody who got one of these to show took pics of how big it was, apparently. Or the Marketing team dictated they all post the same blog post.

"18k resolution" etc; multiple prints made... makes me wonder "made from what?" What kind of "original" are they pulling prints from? Is there some special super high res film transfer box for this? Long ago I had one of those, it was a 6in CRT that did 2k x 2k and that was from the 80s. I'd love to hear about the CRT or whatever they're using to put this kinda resolution on film.