Using a Plumb Line for Accuracy Even the most beautiful paste-the-wall wallpaper can look unprofessional if the strips aren’t straight. To ensure perfect alignment, use a plumb line or a spirit level before applying the first strip. Mark a vertical guideline lightly with a pencil to serve as your reference. Unlike paste-the-paper wallpaper, which can stretch and distort when wet, pas... https://www.arthouse.com/blogs/how-to/a-step-by-step-guide-of-how-to-hang-paste-the-wall-wallpaper