Making A Corner Look Straight When It’s Not

Here I’m hanging wallpaper from right to left, working around this corner. I’ve wrapped the paper 1/8″ around the corner, and then cut a new piece that will overlap that 1/8″ and continue to move to the left. (Search here to learn more about turning inside corners.)
This is a 100 year old house, and this corner is way off-plumb – on both the right side and the left side. The chair rail, however, is perfectly level.
Here, the pattern matches nicely at the bottom of the wall. But as it moves up, the crooked corner takes over, and the pattern becomes mis-aligned.
By hanging the paper crooked, I can match the wallpaper pattern perfectly in the corner. But that will skew the left edge of this new strip off-plumb by slanting it to the right. That means that every subsequent strip will track off-plumb … and the motif at the top of the chair rail will start to climb uphill.
Since the chair rail is so prominently visible, I think it’s more important for the pattern motif to be straight along the chair rail, than to be perfectly matched in the corner.

But I didn’t like the way the pattern was getting un-matched at the upper part of the wall. I thought I could make it look better.
This design gave me something to fiddle with.
One option was to cut the paper vertically between the two rows of “swoops.” Then I could match the pattern in the corner, and pull the excess paper to the left, overlapping one strip on top of the other about 1/4″ at the top and tapering down to nothing at the chair rail. It’s a thin paper in a room with not-great lighting, so this overlapped lip would not be very noticeable. Still, I thought I could make it look better.

I could make the overlap invisible by trimming the paper along the design. Here I’ve removed that corner piece.

On the left is the strip I’ve cut off.

Here I’m putting the strip into place, and making sure that the pattern matches nicely in the corner. This pushes the upper part of this cut strip further to the left, so it overlaps the other strip of paper just a little
Now, instead of a visible straight overlap the full height of the strip, the overlap comes along the rounded edges of the design. That black line disguises the overlap beautifully!

Here it is nicely matched in the corner, with invisible overlap along the curved black line.
The excess still needs to be trimmed off at the ceiling and chair rail.

Mission accomplished! The design matches nicely in the corner, the paper moving to the left is hung perfectly plumb, and the motifs are all at their proper heights along the chair rail and ceiling.

This fun retro mid-century modern pattern is by Designer Wallpapers.