Screen printing represents a printing technique that makes use of a woven mesh in order to support an ink-blocking stencil. The attached stencil opens the very areas of mesh which transfer ink or other printable materials that can be pressed through the mesh as a means of sharp-edged image onto a substrate. The roller or as simply said, squeegee is moved across the screen stencil thereby forcing or pumping ink past the threads of the woven mesh in open areas. Screen printing is also named as silkscreen or seriography.
Screen printing was first appeared in a recognizable form in china under the patronage of Song Dynasty. Japan as well as other Asian countries did adopt this very method of printing and advanced the craft by using it in junction with block printing and hand applied paints. The art of screen printing was introduced to Western Europe and Asia in 18th century.
The technique of screen printing goes as follows:-
The screen is made of porus, finely woven fabric known as mesh that is stretched over a frame of aluminium or wood. Mesh is made up of man-made materials like nylon and polyester etc. Certain areas of the screen are blocked with the help of non-permeable material for forming a stencil that is negative of the image to be printed, i.e. open spaces where the ink will appear.
The screen is placed on the top of paper or fabric. Ink is prepared on top of the screen as well as a fill bar that in turn is used for filling the mesh openings with ink. After that, the operator starts with the fill bar at the rear of the screen as well as behind a reservoir of ink. The operator has to lift the screen for preventing contact with the substrate and uses a few chunks of downward force through pulling the fill bar to the front of the screen. In return, it effectively fills the mesh openings with ink as well as move the ink reservoir in front of the screen.
The operator uses a squeegee bar for moving the mesh down to the substrate as well as pushes the squeegee to the rear of the screen. The ink that is in the mesh opening is quietly pumped or squeezed with the help of capillary action to the substrate in a controlled and prescribed amount.
The major types of screen printing presses involve flat-bed, cylinder and rotary.
A word to note is that textile items that are printed with multi-color designs make use of a wet on wet technique.