Some interesting things have happened in the history of wallpaper. The video below shows how some wallpaper designed by William Morris of the American Arts and Crafts movement was printed, one color at a time.
Sometimes wallpaper was made and marketed to be good for your health. One characteristic that was put forth about some healthful wallpaper is the fact that it was washable, unlike some other types of wallpaper such as the kind that was flocked, which was textured by adding chopped up wool. That wallpaper seemed velvety and was not marketed as washable.
A very interesting article about the history of wallpaper can be found at the Victoria and Albert Museum web site here: https://www.vam.ac.uk/articles/a-brief-history-of-wallpaper
The second video, while a bit long, at around an hour, has a good overview of the history of wallpaper, including a segment on how to make flocked wallpaper, a segment on why some historic green wallpaper could become toxic, and a segment about wallpaper designs that some critics felt depicted three dimensions and perspective with too much realism.