Screen printing is the traditional 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.
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:
Paper Stencil
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 reproduced up to 15 prints.
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 painted. 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.
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.