White edge
From the wallpaper problem solver - quick reference guide
This is a common problem that is especially evident when installing dark coloured background wallcoverings, because the edges show white when butted together.
White edge will show as soon as the product is hung; it does not have to dry first, it is immediately there and will be evident as soon as two pieces are butted together.
How to avoid a white edge when installing wallpaper, especially darker papers
It is the responsibility of the installer to determine if the product can be installed without giving offence to the customer. It is the installer's call to either have the product replaced or to carry on.
Note: This problem should also be identified by the installer by the time the first roll is hung.
If a dark background paper is to be hung, it is wise to colour the ends of the rolls before unrolling.
Some installers use water based felt pens, some use food colouring, others chalk or pastels, to colour the product before it is installed, as it is almost impossible to colour the white edge after the product is on the wall.
To help in this matter, Aspiring Walls have for some time now been colouring the vinyl and spraying the ends of some dark products before despatch.
However, it is the responsibility of the installer to colour the ends of the rolls of wallcovering before hanging.