[WalterBright]

I experience immersion in books. What drops me out of immersion is misspellings. I remember one which was a good story, but about 90% of the pages had at least one misspelling. It's like hitting a pothole when you're driving.

Book misspellings have changed over the years. Since people use spell checkers now, they are of the form:

    He arrived at the top of the stairs painting heavily.

Yes, that's an actual example :-)

With films, I drop out of immersion when seeing things like reflections of the camera crew, anachronisms, etc.

[throwaway290]

It's slightly individual, e.g. some may pick up on misspellings in books (or anachronisms or mismatching sound in video) more easily than others, but my theory is whenever something concerns the story or requires any effort to determine whether it concerns the story or not it breaks immersion.

Misspellings in books, foreign objects or people in a show or film, obviously fake phone numbers and things like that fall into that category.

On the other hand, things like paper quality or font choice (and lens angles, cuts, video resolution, color) tend to not break immersion if the story is right.