|
Screen-printing is a complex process. A science of its own,
a very cool one.
It is accomplished by pushing ink through a stencil on
a silk screen. Kind of like the one on your windows - let’s
say - but much, much finer. The threads are thinner and packed
together (up to 260 strands per inch.).
The screen can be
stenciled on in different ways, but photographically is the
best way to do it.
You start with the art work - it gets separated into respective
colors or plates. Then, you make photo positives, which you
use for making a photographic stencil on the screen.
The screen is prepared like this... the screen is coated
with a photosensitive emulsion and left to dry. Then the
artwork/photopositives are adhered to the now dry coated
screen and exposed to high amplitude light.
The film positive is clear, but where the image is... it
is a dense black. And so, where the light goes thru the clear,
the light hits the coated screen and sets it and hardens
the emulsion. Where the image is black... the light does
not reach the screen and so, those places untouched by the
light stay soft and wash out with water - creating the stencil
for the ink to go thru.
AND VIOLA! YOU HAVE A STENCIL
Ready to print on almost anything!
Screen-printing involves the art of photonegative and positive
making, a science of its own too. With a concept dating back
to the 16th century (or further back!) mastered by JOHANN
HEINRICH.
In 1727 he uncovered the fact that certain chemicals, especially
silver halides, retain photosensitive properties, which make
silver colloidal substances turn to dark when exposed to
light.
Many other discoveries and chemicals inventions make screen-printing
possible - like the production of high quality inks and solvents,
and the development of fabric spinners which produce fabrics,
which get old and provide us with lots of rags for cleaning
up the mess screen-printing makes.
The inks are special...
It takes lots of experience and know how when screen-printing.
Not just any ink will stick to a given surface material.
For metals, enamel inks are used. For banners and decals,
vinyl inks are used.
For other kinds of materials like wood and plastics plastic
inks might be used. This is not a written rule - it really
depends on the material and requires testing.
At RD Screendesign, the artists’ 20 + years of
experience work to your advantage.
Screen-printing is supposed to last outdoors, in harsh weather
where other forms of printing would just fade crumble or
wash away.
Screen-printing is fun, it is cool, and we still marvel
at the fact that the whole process is even possible. It is
magic... and a trade well worth learning. |