IMAX film is twice as wide as standard film. 70 mm instead of 35 mm. The IMAX film platters are physically ginormous. All that extra film gives you a bunch of extra resolution compared to regular film.

The first catch is that “IMAX standard” may not be real IMAX. I don’t know exactly what that means. Perhaps it could even be digital projection that aims to be comparable to IMAX in some ways?

Second catch is that a lot of films that are shown in IMAX theaters were not actually shot on IMAX originally. If a film was shot on 35mm, say, and then printed onto IMAX, you don’t get all of the resolution benefits, and you may also get letter boxes or pan-and-scan because the aspect ratio isn’t the same. IMAX cameras are massively more expensive and logistically difficult than regular film cameras.