Faint black lines have started to appear along the wallpaper seams.
They are very thin and not very noticeable, but once you start noticing them, they keep bothering you.
This is how it looked about a year after the wallpaper was put up.
An effective way to fill these gaps is to use joint caulk.
Here is a photo after the work.
Up close there is a slight difference in texture, but once it dries the gloss fades and it becomes almost invisible.
That solved the gap problem.
Joint caulk can neatly fill not only gaps in wallpaper but also thumbtack holes.
Here is a photo before the repair.
And here is a photo after the repair.
Unless someone points out the repaired spot, you would never notice it.
