Painting a wall, what to do with this crack

[Josephi]

I’m going to paint one of the bedrooms but I’m not sure what to do with a hairline crack. I’m tempted to just buff it with some sand paper but then that would not fix it I guess. Would anyone have any experience or advice?

Sand it, Pollyfilla it, let it properly dry out, sand it again. Repeat if necessary.

Always do as much prep as you can before painting, you'll get a better result. Don't just go charging straight in with the paintbrush! Tempting, I know.

Cut it out, a v-shaped groove into the plaster with a Stanley knife. Then fill, sand paint etc. That's the correct way. However, it's probably a slight weakness in the structure and may well reappear. I have one in a similar which always comes back.

Would it be worth literally papering over the crack? Do the repairs then use lining paper on the wall before painting?

That’s the plasterboard join. It will always crack unless you make a ‘proper’ repair which is beyond most people.
I agree with your suggestion to use paper after following the previous advice.

Thank you!!!!