What causes seams on wallpaper borders to curl?

For the homeowner with wallpaper borders that curl away from the wall, the question many of these homeowners have is about what causes these borders to curl, how can you repair these curls, and how can you prevent this from happening next time you install wallpaper borders.

Wallpaper Border Curl Causes

Borders curl mostly because of two things: a) they dry up before they are securely glued to the wall surface; and b) the paste is too thin or too dry to securely glue the seams. When this happens they separate from the wall, become dry, and begin to curl.