All About Screen Printing

Screen printing is a printing technique that was first used over 2000 years ago by the Chinese. The general process involves passing ink through a mesh screen that has been firmly stretched onto a frame. Prior to applying the ink, a stencil has been placed upon the screen so that an image will present itself once the stencil is removed. Sections of the screen can be masked to prevent ink from appearing in those areas. Once the image has imprinted onto the stretched mesh, the item is sent through a heat-tunnel to settle the image. This curing process allows the ink to dry quickly so that they are able to be packaged and stacked. Since screen printing can be used on various materials, today you will see this technique used on items such as CD covers, cotton fabrics, polyesters and silk, posters, clothing, watch dials, flyers and signs.

When screen printing was first introduced, the screen was created from human hair stretched across a frame. Stencils were made from various leaves formed into shapes. The Japanese evolved the screen printing process by using silk screens and lacquer stencils. This is where the popular term ‘silk screening’ originated. Samuel Simon patented the first industrial screen printing method in 1907. Years later, John Pilsworth would introduce multi-colored screen printing which became widely popular. Colored screen printing involves blocking out and alternating different areas of the screen to add various colors.

There are several methods to creating stencils for screen printing. The most common method is known as photo emulsion and has been used for the last 70 years. The process begins by drawing or painting the image directly onto a transparent overlay such as tracing paper. The screen is then coated with emulsion and allowed time to fully dry in a dark area. The overlay is then placed over the screen and exposed to ultraviolet light. The UV light hardens the emulsion to create the image. The final step is to wash off the screen to leave a negative stencil of the image. To make the process of screen printing easier, many companies presented the printing press. The printing press creates multiple copies of a screen design onto garments or other various items.

Screen printing can be done completely by hand or by a machine or manual printing press. Typical printing presses come in four or six color models. There have been several variations of the printing press that have appeared over time and featured various sizes and shapes. Blocks of symbols, letters or images are locked into place and then pressed into ink to leave an impression. To create a screen print, various inks and screens can be used. The most common type of ink is called plastisol which provide rich colors and clear detail. Water based inks create a softer feel and are useful for larger printing areas. Discharge inks are typically used to print light colors onto dark backgrounds. Other print screen techniques can be added onto print screens such as flocking (for a mirrored finish), using caviar beads, expanding inks, mirrored silver or a clear gloss to give a shiny finish.