Screen printing, also known as serigraphy, is a versatile and widely used printing technique that involves forcing ink through a mesh screen onto a substrate. The magic of screen printing lies in its ability to create stencils on the screen, allowing ink to pass through only in desired areas, thus forming the print. This method is celebrated for its capacity to apply vibrant colors to a variety of materials, from paper and fabric to wood and plastic.
At the heart of screen printing is the screen itself. This crucial component consists of a fine mesh stretched tautly over a frame, traditionally made of wood or metal. While silk was historically the material of choice for the mesh, modern screen printing predominantly utilizes synthetic fabrics like terylene due to their durability and consistency. The tightness and fineness of the mesh are essential for achieving sharp and detailed prints.
Creating a stencil is the next vital step in the screen printing process. Stencils act as barriers, blocking ink from passing through certain areas of the screen to create the desired image. These stencils can be crafted from diverse materials, including paper, fabric, greasy paints, or designs on transparent films. There are several methods for applying stencils to the screen: direct placement, painting directly onto the screen, or utilizing photo-sensitive emulsions to transfer designs. The photo-sensitive emulsion technique, which involves transferring a design from a transparency or Mylar film, has become the most prevalent method in contemporary screen printing due to its precision and versatility. Designs for transparencies can be created by hand using opaque inks, digitally printed, or cut from UV-masking films like rubylith.
The process of transferring a design using photo emulsion begins with coating the screen with a thin, even layer of photo-sensitive emulsion. This is achieved using a scoop coater, a specialized tool with a smooth edge that ensures uniform application.
Once the emulsion is completely dry, the design transparency is carefully positioned against the emulsion-coated screen.
The screen and transparency are then placed in an exposure unit that emits ultraviolet (UV) light. During exposure, the design on the transparency blocks UV light, preventing the emulsion beneath it from hardening. The areas of emulsion surrounding the design are exposed to the UV light and consequently harden.
After exposure, the screen is washed. The unhardened emulsion, protected by the design during UV exposure, washes away, leaving behind the stencil – the open areas of mesh that correspond to the design, ready for printing.
With the stencil prepared, the screen is secured in hinges on a printing board or table. These tables often feature vacuum holes to hold paper in place during printing, ensuring precision. A bead of screen printing ink is applied to the top of the screen, and a squeegee is used to pull the ink evenly across the stencil area, a process known as “flooding” the screen.
Next, a sheet of paper or the chosen substrate is placed under the screen. Another pass of the squeegee forces the ink through the open areas of the stencil and onto the substrate, creating the printed image. The direction of the squeegee stroke dictates the ink deposit.
For designs requiring multiple colors, the screen printing process is repeated for each color layer, using a separate stencil for each. Precise registration, or alignment, of the paper and screen is crucial to maintain the accuracy and sharpness of the final multi-colored print.
Screen printing’s versatility and ability to produce bold, vibrant images have made it a favorite technique for artists and commercial applications alike. From fine art prints to textiles and signage, screen printing continues to be a powerful and adaptable method of image reproduction.
Liz Zanis (American, born 1980). Memory Sticks, from APS Certificate, 2018. Screenprint and screen. Courtesy of the artist
