Straight line cracks in paint - is it a problem with underlying plaster

[RMacD]

Hello, absolute novice here. The paint in my bathroom has cracked all around the room in perfect straight lines (see first 2 photos). When I’ve chipped off the loose paint and sanded it back there seems to be a paler line of plaster underneath where the crack was (see last 2 photos). What’s going on here? Will it come back if I repaint? Many thanks for your help!

 

[Spitandpolish]

Yes

 

[Cockney]

Hello, absolute novice here. The paint in my bathroom has cracked all around the room in perfect straight lines (see first 2 photos). When I’ve chipped off the loose paint and sanded it back there seems to be a paler line of plaster underneath where the crack was (see last 2 photos). What’s going on here? Will it come back if I repaint? Many thanks for your help!

@essexandy

 

[essexandy]

Yes.
Paint isn't very good at curing structural cracks.
Nor is plaster.

 

[bobski]

Hello, absolute novice here. The paint in my bathroom has cracked all around the room in perfect straight lines (see first 2 photos). When I’ve chipped off the loose paint and sanded it back there seems to be a paler line of plaster underneath where the crack was (see last 2 photos). What’s going on here? Will it come back if I repaint? Many thanks for your help!

Ceilings or walls?

 

[Monkey Boy]

Yes.
Paint isn't very good at curing structural cracks.
Nor is plaster.

Foam is @ChrispyUK

 

[ChrispyUK]

Foam is @ChrispyUK

Go to bed