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.