So What is Screen Printing Anyway?
The Printing Process Explained
Screen printing or Silk Screening is a manual process where ink is pushed through a mesh screen (traditionally made of silk) to create an image on to a surface – in this case, paper.
Every one of my screen printed products starts with a sketch. I carry a notebook to jot down ideas or make thumbnail sketches for ideas I have for cards or prints. I often go right to the computer and make my sketches with my tablet in Adobe Illustrator. Once I’ve got the initial concept down, I start to refine the drawing, smoothing the lines, adding hand drawn text, and playing with colour. Designing for screen printing forces me to be creative with the way I use colour. Keeping the colours in each print to 3 or fewer is ideal.
After the drawing is complete and I’m ready to print, I create separations in Adobe Photoshop so that each colour can be printed on its own layer. Separations are done in black and white. I closely inspect every part of the image to make sure that I have enough trapping (overlapping of colours), that the lines are smooth, and I’m not missing any elements on any layers. The separations are then printed onto vellum on my laser printer and I prepare for the exposure process. I coat an aluminum screen for each colour with a thin layer of a photosensitive emulsion and allow the screens to completely dry in the dark.
When dry, I place the screen down on my exposure unit with the vellum on top. A piece of glass holds the vellum in place as I expose the whole thing with a 500W bulb. As the light hits the emulsion, it hardens. Once the screen has been exposed for about 20 minutes, I turn the light off and rinse out the screen with water. Anything that was blocked by the blacked out parts of the vellum washes out and leaves me with a stencil that I can use for printing. This process is completed for each colour.
I then begin the registration process. Each colour must be lined up exactly so that the finished product meets my quality standards. I use paper bumpers and hinge clamps to make sure my registration is as accurate as possible.
Ink is placed on the top of the screen and pushed through using a squeegee. I print each card or print, 1 colour at a time, allowing each to dry before printing the next colour.
Once I’ve printed each colour and the cards or prints are dry, I cut them to size and check for quality. Any misprints are pulled from the run and discarded.