Although there are many styles and methods of screen printing, you will need to use some basic tools to produce a variety of designs. Screen printing is a technique that reproduces a design by transferring ink through a stencil mesh screen onto a substrate. The technique is sometimes referred to as screen printing or silk screen printing. To fill the open area of the die, move the screen printing squeegee across the screen and then use a reverse stroke to wet the substrate with ink along the contact line. If a multi-colour design or image is to be produced, the colours must be printed one at a time and multiple screens are required, one for each colour, so that the colours do not bleed together and become muddy. If a monochrome design is to be produced, only one screen is required.
One of the most basic tools for screen printing, you can use a rubber squeegee to scrape it across the screen in order to distribute the selected ink evenly. Although there are automated machines that can do this, many companies use a manual ink press as it can help better control quality and is much faster for small print runs.
The choice of squeegee depends on the ink used, the number of screens and the final design. They also come in different durometers, the most common being 60, 70 and 80. 60 durometer squeegees are considered softer and tend to print more ink than harder inks such as 80 durometer squeegees. 60 durometer squeegees are best suited to printing white ink or any highly opaque coloured ink on dark fabrics. 70 durometer squeegees are the most commonly used squeegees and are particularly suited to printing on white or light coloured The 80 durometer squeegee is the hardest of the three and should be used in combination with higher screen counts, fine detail or halftones.
Photographic emulsions are used when creating stencils. Essentially, you lay a thin layer of light-sensitive emulsion on the screen and then allow it to dry in the dark. Then, take a darkened image on a translucent surface (such as tracing paper), place the image on the screen and expose the screen to light. Wherever the light hits, it will harden the emulsion. However, the design or blackened areas should be blocked from the light. The blocked areas will not harden and you can rinse them off with water once exposed. This technique allows you to improve the accuracy of your designs and thus make mass production easier.
Transparencies are simply thin pieces of translucent, flexible material on which you can draw designs or images and then transfer them to a screen coated with a light-sensitive emulsion by exposing them to light. To create a design using transparent paper, convert your design to a black and white image. Grayscale images or images in grey levels that are already black and white will not work properly. You can also use Adobe or other photo software to edit the design, which can then be transferred to paper.
The scoop coater facilitates the direct application of liquid emulsions. This is a slot-like tool that covers the screen with a smooth layer of latex. You grasp the scoop coater with both hands and place the sharp edge about an inch above the bottom of the inside of the screen frame.
Types of screen printing range from 1-colour presses to 4-colour presses. Single-colour printing can be done using a lively hinge, while multi-colour presses use multiple screens.