Screen printing is a printing technique whereby a mesh is used to transfer ink onto a substrate, except in areas made impermeable to the ink by a blocking stencil. A blade or squeegee is moved across the screen to fill the open mesh apertures with ink, and a reverse stroke then causes the screen to touch the substrate momentarily along a line of contact. This causes the ink to wet the substrate and be pulled out of the mesh apertures as the screen springs back after the blade has passed.
Screen printing is also a stencil method of print making in which a design is imposed on a screen of polyester or other fine mesh, with blank areas coated with an impermeable substance. Ink is forced into the mesh openings by the fill blade or squeegee and by wetting the substrate, transferred onto the printing surface during the squeegee stroke. As the screen rebounds away from the substrate the ink remains on the substrate. It is also known as silk-screen, screen, serigraphy, and serigraph printing. One color is printed at a time, so several screens can be used to produce a multicoloured image or design.
There are various terms used for what is essentially the same technique. Traditionally the process was called screen printing or silkscreen printing because silk was used in the process prior to the invention of polyester mesh. Currently, synthetic threads are commonly used in the screen printing process. The most popular mesh in general use is made of polyester. There are special-use mesh materials of nylon and stainless steel available to the screen printer. There are also different types of mesh size which will determine the outcome and look of the finished design on the material.
The Basic Screen Printing Process
In screen printing, the screen is first created by stretching a fabric (eg silk) over a frame of wood or aluminium. The image is first drawn (manually or with software) on a piece of paper or plastic, or captured in a photograph. Then it is cut out to form a stencil. Next, the stencil is attached to the screen. Then areas of the screen mesh are blocked with a waterproof masking medium. These areas become the negative areas of the final image. The screen is then placed over the desired substrate (eg. paper, glass, textile) and ink is then applied to top of the screen and spread across the screen, over the stencil and through the open mesh onto the substrate underneath. The ink is spread using a squeegee - a rubber blade usually the same width as the screen. The unblocked area is where the ink filters through and creates the image. Any number of colours can be used, although a separate screen is required for each colour.
Tim Pitsiulak working on the drawings Swimming Bear and Tattooed Whale for the 2017 Cape Dorset Spring Release at Open Studio (Toronto)
PREPARING THE TRANSPARENCY
Once the original drawing is complete a transparency is made for each colour that will be printed.
PREPARING THE SCREEN
Film Images Used in Silkscreen Printing
Using modern technology with UV sensitive photo emulsions, images can be created on transparent film and then replicated exactly on a nylon screen coated with light sensitive (UV) emulsion. The latter is applied to the whole screen which is then overlaid with the film upon which the artist has drawn his design, and both are exposed to UV light. The light passes through the transparent film, except where the artist's design prevents it. On those parts of the screen exposed to the light, the emulsion hardens. When the screen is then washed, all the emulsion is removed except for the hardened areas, thus creating a stencil on the screen that exactly matches the design down to the smallest detail.
Open Studio's Miles Ingrassia and Nicholas Shick (printers) preparing one of the screens for printing.
After all the screens are prepared for each colour a trial proof is made for the artist to look over and make any changes necessary before the production of the edition is printed.
PRINTING THE EDITION
Once the trial proofing is complete the edition can be printed. For the 2017 Cape Dorset Spring Release an edition of 50 prints were made at Open Studio and signed by the artist Tim Pitsiulak.