Another printing method is to print by forcing ink through openings or holes in a stencil, Figure 1-8.
One common type of stencil printing is screen-process printing. This method is also called stencil printing, screen printing and silk screen printing.
STENCILS. The stencil controls what is to be printed. Basically a stencil is nothing more than a thin sheet of paper, film, or other nonporous material with lettering or a design cutthrough. The lettering or design is right reading not reversed. Stencils for screen-process printing may be hand cut from paper or film, prepared photographically, or painted directly on the screen.
PRINTING SCREENS. Astencil with open areas representing the desired image must be adhered to a screen. A screen is a piece of woven material, such as silk, nylon, dacron or stainless steel mesh, stretched tightly over a wooden or metal frame. The frame serves as the printing press in screen-process printing. A simple printing frame is shown in Figure 1-9.
THE PRINTING PROCESS. Screen-process printing is easy to understand. After paper is placed under the printing screen, ink with a paint-like consistency is applied to the top of the screen. Finally, the ink is spread and forced through stencil openings onto the paper below the screen. This is done by pulling a rubber squeegee over the screen. The screen process of printing is illustrated in Figure 1-10.
The idea of applying decorations to objects by stenciling is very old. Evidence shows that stenciling techniques were wedely used in china to decorate pottery and other objects.
Screen-process printing developed rapidly duing the early twentieth century. Awide variety of stencil materials materials has been developed over the years. Today, just about any surface of any shape or size can beprinted using screen-process methods.