How Is Wallpaper Made?
Wallpaper has evolved considerably since its first appearance in 13th Century Europe as "domino papers," which were hand-painted with religious icons. In the 21st Century, the most common wallpaper is machine-made and vinyl-coated, and consists of a backing, a ground coat, and applied ink. The wallpaper design is usually printed using one of four techniques: surface printing, gravure printing, silk screen printing, or rotary printing.
Wallpaper backing is either woven (fabric-based) or nonwoven (paper-based). Nonwoven backing is manufactured from wood, wood pulp, or a mixture of wood pulp and synthetic material. Woven backing is made of a durable textile.
Wallpaper ground coat is applied to the backing, providing the the printed design's background color. The ground coat is usually a latex or vinyl (PVC) mixture applied evenly to the backing by an applicator roller. After ground coat application, the wallpaper is ready for printing.
Surface printing is a process which uses raised rubber patterns attached to metal rollers. Ink on the rollers transfers the raised patterns to the paper, resulting in images less crisp than those printed with other methods.
Gravure printing, or intaglio, offers an unlimited palette of colors and shades. For gravure printing, designs are etched into hard rollers. The depth of the etching determines the amount of ink that will collect in the recessed pockets and be absorbed by the paper, which determines the tone of the color.
Silk screen printing can be applied by hand or can be done by machine in a process known as "flat bed automatic printing." In silk screen printing, a photographically produced stencil is created for each desired color. Each stencil is transferred to a screen stretched on a frame. The stencil allows each ink to penetrate to the wallpaper only in the areas where that particular color is needed.
In rotary printing, a cylindrical screen with tiny screen openings forms a mesh stencil which is wrapped around hollow tubes within a machine. The size of the openings controls the amount of ink to be applied. Ink flows continuously through the tubes onto the paper.