Negative hallucinations under hypnosis are a decently documented phenomena.
In Suggested negative visual hallucinations in hypnotic subjects: When no means yes.
Spanos, Nicholas et al write:
45 undergraduates with high scores on the objective dimension of the Carleton University Responsiveness to Suggestion Scale were hypnotized. Ss were given the suggestion that they would see a blank sheet of paper on opening their eyes. On the paper was a clearly visible number 8. Only 15 Ss repeatedly reported seeing nothing on the page. In a posthypnotic interview designed to subtly pressure Ss into giving accurate descriptions, all but 1 of the 15 negative hallucinators reported correctly that the target was the number 8. Findings demonstrate the rarity of negative hallucination responding and its correlation with indexes of hypnotizability.
It's no easy phenomena but it exists well enough to be documented in studies.
As far as (2) goes, I'm not aware of this being well demonstrated. If the person however already knows what written on the page and they should be able to see the page, they will tell you what's written on the page.
It's like seeing colors of objects at the rand of your normal visual field. Those objects don't appear to be colorless but your eyes can only perceive colors near the center of your visual field. The colors that you see at the rand of your visual field are the best effort your brain makes to determine the color of those objects.