Screen printing (or silk screen printing) is a completely different method of printmaking to those we have demonstrated so far, and instead of taking a print directly from a plate or block, the ink passes through a mesh (i.e. the screen), onto the printing paper which is placed underneath. On the mesh itself various forms of stencils are created to stop the ink from passing through in those areas.
Screen printing has the quality of being able to produce even, flat areas of colour. Often brightly coloured images or very graphic designs are associated with screen printing. As well as being used for a fine art purpose, screen printing is used for t-shirt printing, fabric printing and other commercial purposes such as signs and posters. All these different purposes use different types of inks and different forms of stencils appropriate for the final usage of the ‘print’.
The stencil is created on the screen in many different ways and in this module we will demonstrate just a few simple methods that can be carried out without specialist equipment. There are far more complex methods that can be pursued further once these basic methods have been mastered. Once a stencil is created it is then a fairly quick process to produce a relatively large edition of prints.
The Tools Needed for Screen Printing
The Screen
The first item needed is a screen. This is a wooden or aluminium frame with a fabric mesh (in the past this fabric would have been silk, hence the term silk screen) stretched very tightly over it. Screens come in different sizes and with different mesh counts. A screen with a mesh count of 120 is much finer than a screen with a count of 60.
This means that a screen of 120 has 120 tiny openings between the threads per inch and a 60 screen has only 60 – i.e. these are bigger holes. When carrying out very fine work a finer mesh is used (for example with more photographic work) and work using large flat areas of colour and with textile, printing a mesh with a lower count will be used.
Screens either come ready stretched or you can stretch the mesh over the frame yourself. To start with it is probably easier to buy a small ready stretched screen to make sure that it is correctly taught enough and to gain some experience. When stretching screens it is easier to use a wooden screen, because the mesh can be stapled in a similar method to creating a canvas for painting. With aluminium frames (although they have the benefit of being lighter and less likely to warp), a special stretching frame and glue will be needed instead of staples. The mesh also comes in different colours, the most common being yellow and white. These are mainly due to the way that they receive light when a screen is exposed in a photographic process with a light sensitive emulsion coating to create a stencil. We are not dealing with ‘exposed’ screens during this module.
A standard 90T screen is recommended for screen printing onto paper, but as we are dealing with hand cut stencils a lower count will also work for these bold designs.
Squeegee
This simple tool consists of a rubber blade fixed into a wooden handle. (Similar to a window wiper blade on a car but a lot thicker). This tool is used to push the ink through the mesh on the screen. Again squeegees come in different sizes and the rubber blades come in different softnesses. As a general rule, your squeegee should be smaller than your screen so that it fits comfortably into the inside of the frame with a few inches either side. It is also useful to have a smaller squeegee available for pulling smaller amounts of ink through the screen.
Screenprinting Ink
Either water-based or oil-based inks can be used for the purposes of screen printing. All the inks are very different in consistency and quality to any of the inks that we have used so far for relief and intaglio printing.
In the past mainly oil-based inks were used (and still are in more commercial forms of screen printing) but mainly non-toxic safe water-based inks are now used by artists and in educational environments that are just as good as oil based inks.
Water-based inks have the advantage that they are non toxic, easy to clean up and do not require strong chemicals such as turpentine to remove them.
Most printmaking suppliers will be able to supply a good water- based system of printmaking inks that produce good results and are safe and easy to use. The System 3 Acrylics range, mixed with a screen printing medium, or the speedball system of inks are a good starting point and readily available in most art shops.
Paper Similar quality paper can be used for screen printing as any other process. Again a smooth surfaced paper will work well with the flat even colour pushed through the screen.
A Screen Bed Many screen printing studios come equipped with large screen printing tables. These specially designed tables allow you to fix the screen in place into a frame so you can lower the screen up and down with ease. The table has lots of tiny holes in it with a vacuum pump underneath so that when the paper is laid on the table, the vacuum effect keeps it stuck to the table and not to the screen. They also have large metal arms to which you fix the squeegee, to apply even pressure when working with very large screens.
When printing from home a simple MDF / plywood board or a wooden table as the base and some hinges or clamps to fix the screen at the back so you can lift it will do.
In the diagram above we have shown a picture of a simple plywood screen bed constructed for a wooden screen. A piece of plywood was cut to a size larger than the screen. A piece of wood the same height as the wooden screen frame was glued and nailed to the back to secure it in place. A set of hinges was then attached to the edge of the frame and the wood so that the screen can be lifted up and down with ease. The hinges instead of being fixed, have a small metal pin that can be removed from the centre so that the screen can be detached for cleaning, and further screens can be fixed in place too. All the materials needed to construct this simple screen bed can be bought at your local DIY store. Another simple method is to have a small piece of wood clamped to the edge of your desk the same size as the screen and the screen can rest against this when printing. Just make pencil marks on the wood where the edges of the screen should be.
Let’s get screenprinting...
Now the basic tools and materials of screen printing have been introduced, the following sections will demonstrate 3 different ways of creating a stencil to use with a screen. Hopefully some of the principles and ways of dealing with stencils and multiple coloured prints we have already covered will enable you to tackle screen printing with a creative approach and good idea of how to print several layers of colour.
