Screen printing a method of printing images onto fabric and paper. It is possible to duplicate an image many times using a simple stencil placed on the silk screen. An ink colour is poured onto the screen to one side of the stencil and then dragged across the stencil using a squeegee. The ink is pushed through the fine mesh of the screen and transferred to the fabric or paper. The areas of fabric or paper masked by the stencil remain untouched.
The printing process can be repeated along a length of fabric making it possible to create unique printed fabric for curtains, bed linen, clothing and more. Alternatively, the screen can be used to print items such as T-shirts, posters, cards, scarves and ties.
To make screen prints with more than one colour a new stencil is used obscuring or revealing areas of the previously printed material.
George Weil offers the Selectasine System of pigments and binders for custom making water-based inks for screen printing. The binders include a puff binder which rises when it is heat-set and a metallic binder which is formulated for taking metallic pigments such as the Selectasine metallic pigments and Jacquard Pearl-Ex. The full range, which includes luminous colours and very opaque white, can be mixed to create the full range of screen printing inks for screen printing techniques.
The ready-mixed screen printing inks include Speedball Acrylic Screen Printing Inks for use on paper and board and Speedball Fabric Screen Printing Inks for cotton, polyester and other synthetic fabrics. The colours are intermixable and have good wash fastness. There are also two excellent value screen printing kits from Speedball which give the beginner the inks and equipment to experience the craft for the first time.
Screen Printing Tips for Speedball Inks
- Use fabrics free of sizing. Many have a coating, which sits on the fibre and prevents the screen printing inks from bonding with the fabric. It’s always worth testing the fabric first.
- Pre-wet the screen with a damp cloth before inking. This will help prevent ink thickening. The ink can be thinned with up to 5% water.
- Stir the screen printing inks well before using. Print with a loose 'flood stroke'. Avoid thick or multiple coats which can affect wash fastness.
- Mix the ink with Speedball Transparent Base for transparency, economy, and a softer hand. Mix with up to 10 percent Speedball Retarder Base during periods of low relative humidity, high temperature, or slow printing.
- During breaks of ten to fifteen minutes, mist the ink in the screen with water using a spray bottle. For longer breaks, wash the screen thoroughly with water. Always keep the lid tightly sealed to prevent skin forming on the surface of the ink in the container.
- Wash the screen with water immediately after use. After the ink is thoroughly cleaned out, use normal stencil reclaiming.
- Protect the inks from freezing and do not store above 35°C for extended periods. At 20°C, inks have a shelf life of two years from manufacture.
- Buy a book or use the internet to pick up information and tips. Other techniques can be explored with screen printing. Discharge paste can be used to discharge colour from acid dyed fabrics and devoré paste can be used to remove the pile from velvet.
Creating the Printing Mask / Stencil
There are several ways to create a screen which holds the printing mask. At the simplest the screen merely supports a mask which is dropped into place. The mask can also be created by painting a filler on to the screen, which is then cured to an effective block. Each of the methods are described below:
This is the fastest, simplest and least expensive way to prepare a screen for screen printing. First cut out your design from a strong paper or acetate sheet. Position the paper or fabric to be printed under the frame, put the cut-outs in place and lower the screen.
Press down on the screen frame to ensure complete contact with the cut-out. The first drag of the paint loaded squeegee will stick the stencil to the screen mesh creating a stencil that can produce up to 15 prints.
Screen Filler (Negative)
Speedball have developed a simple system for screen printing onto fabrics and paper which does away with the traditional cut-out stencils.
- Preparing the screen using Drawing Fluid or Screen Filler is simple as you can easily follow a design set beneath the screen.
- Screen filler blocks out areas of the screen to stop the ink from penetrating. Place the screen over your design and trace it directly onto the screen with a soft lead pencil. Paint the areas of the screen that you do not want to print with the screen filler, ensuring that the screen is slightly raised above any surfaces. When all required areas are blocked, turn over the screen and clean up the edges of the design.
- Allow to dry overnight before printing.
Drawing Fluid with Screen Filler (Positive)
With this method, the areas of the design to be printed are first blocked out with the drawing fluid.
- Trace a design onto the screen and paint over the areas to be printed. Allow to dry before applying a coat of Screen Filler to the whole of the screen with a squeegee.
- When dry, spray cold water onto both sides of the screen, concentrating on the area covered by the drawing fluid. The drawing fluid will dissolve leaving an area through which the inks can pass.
- Allow the screen to dry thoroughly before printing.
- After printing is completed the screen should be washed immediately and lightly scrubbed using hot water and a strong cleaner such as 'Cif' cream or household bleach. It is then ready for reuse.
Speedball Diazo System
(See also the Selectasine Diazo Photo Emulsion technique)
The Speedball Diazo System is an exciting method of screen printing, for fine line drawings and photographic half tone prints, giving over 300 prints on polyester or synthetic screen materials. Full instructions are available with the products.
- Prepare the resist by mixing the photo emulsion and sensitizer; the sensitised liquid can be kept for 2 months at room temperature and up to 10 months in a refrigerator.
- Spread a thin, even coat of the mixed liquids on both sides of the screen. Allow the screen to dry thoroughly away from light and heat. The prepared screen will keep for up to 2 weeks, away from light, until it is ready to be used.
- A black, high contrast image on an acetate sheet is the ideal master. The resist needs to be exposed to a light source (150W clear incandescent bulb or photoflood) held 30cm above the screen. Exposure times range from 10-90 mins, depending on the screen size and light source.
- After exposure the unwanted emulsion is removed from the screen with Photo Emulsion Remover and the screen can be reused by scrubbing with household detergent, applied within a few days of the original screen preparation.